AN50007

Applying ISO standard conducted transients to MOSFETs in
12 V, 24 V and 48 V systems
Rev. 1.0 — 8 April 2021

application note

Document information
Information

Content

Keywords

automotive, MOSFET, RBP, battery, transient

Abstract

Battery line transients are discussed and simulated for Reverse Battery Protection (RBP) functionsin 12 V, 24 V and 48 V battery systems. The MOSFETs used in these applications must have adrain-source voltage rating that is sufficient to survive the largest transient impressed across themand be able to dissipate any avalanche energy. Care must be taken to ensure RBP MOSFETs areproperly enhanced when large currents are being demanded by the load. Guidance is provided
to clarify that negative transients can cause avalanche in RBP circuits and how to design for thismode of operation.

AN50007

Nexperia

Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems

1. Introduction
This application note examines the effect of applying a selection of conducted battery linetransients to Reverse Battery Protection (RBP) circuits that use an N-Channel MOSFET. The
battery line transients are described in ISO 21780:2020 for 48 V systems and in ISO 7637-2:2011,
ISO 16750-2:2012 §4.6.4 for 12 V/24 V battery systems. These specifications apply to roadvehicles.
Losses in RBP applications are predominantly due to conduction losses. i.e. current flow throughthe MOSFET channel on resistance, RDSon. To reduce dissipation in 12 V and 24 V systems theengineer has a choice to use a lower Drain to Source Voltage (VDS) rated part to achieve a lower
RDSon e.g. BUK7Y4R8-60E. Dissipation is given by the product of the square of the Drain current
2
and channel resistance, ID * RDSon so changing from a 7.8 mΩ part to a 4.8 mΩ lowers dissipation
by 4.8/7.8*100% or ~60%.
The intention here is to illustrate what is happening to the MOSFET (the immunity it has to the ISO
pulse) in-circuit so that its safe operating parameters are respected. Examples are used for theillustrations with detailed narrative to explain the context of the test within the vehicle environment.
Although the ISO specifications are largely prescriptive in some cases OEMs do have liberty toapply them in terms of specifying certain boundary conditions e.g. source generator voltage orresistance.
Interactive application note IAN50007 includes Cloud based simulations, where baseline circuits
have been constructed. The reader is encouraged to visit the web page and experiment with thosesimulations within those boundary conditions. All circuitry is predicated upon N-Channel MOSFET
devices operating in an ambient temperature of 23 ±5 °C per guideline. Five conducted immunity
transients are discussed.
1. ISO 7637-2:2011 pulse 1 for 12 V systems having to be immune to supply line disconnections
which produce large negative transients
2. ISO 7637-2:2011 pulse 1 for 24 V systems having to be immune to supply line disconnections
which produce large negative transients
3. ISO 16750-2:2012 §4.6.4 for 12 V and 24 V systems with Test A applied for systems having to
be immune to Unsuppressed Load Dump transients
4. ISO 16750-2:2012 §4.6.4 for 12 V and 24 V systems with Test B applied for those systems with
Centralized Load Dump protection
5. ISO 21780:2020 Test-03: Short term overvoltage and Test-04: supply component load dump
control test.
The iso.org indicates at some future date replacement of the above by ISO/CD 7637-2 and ISO
16750-2 by ISO/AWI 16750.

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems

2. ISO 7637-2 pulse 1
The specification makes mention of methods to monitor fast and slow emission transients but thefocus here is on modelling the immunity test set up of the DUT. The wave shape is designed to
mimic a situation where the battery supply is disconnected. Referring to Fig. 1, after disconnection
from the source by S1 the Device Under Test (DUT) is exposed to the negative going voltages orback EMF transients produced by the collapse of magnetic fields in neighbour inductive loads on
the same supply line as the DUT.
Examples of disconnection given in the specification are of a fuse being blown or pulled, there may
be a disconnection/break in the harness supply or simply an open circuit as a result of turning off
the ignition switch. Although in some systems the ignition line is simply a low current signal intoa DUT which contains circuitry to switch on an external Main Power Relay or internal Solid State
Relay, in this application note we consider the connections as described below.
Fig. 1 helps visualise how the DUT can be affected by the inductive loads in the system. Once
S1 ignition switch opens the back EMF transient produced is conducted into the DUT. The load
resistance in parallel with the DUT is that created by the other devices sharing the same power
NET. The harness forms loop resistances with these neighbour devices. The Original Equipment
Manufacturer has visibility of the system and can define the value of this parallel load resistance Rs
in the Customer Requirement Document.
UA

0V

1

5

Us

2

3

4

Key

Fig. 1.

AN50007

application note1

ignition switch2

inductive load

3

load Rs

4

DUT

5

power supply

aaa-033294

Circuit diagram that can produce ISO 7637-2 pulse 1

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems

2.1. Simulating the conducted immunity transient - test waveform
Fig. 1 indicates when such a conducted transient will develop. The wave shape shown in Fig. 2 andparameter settings given in Table 1 reveal the configuration of the ISO 7637-2 pulse 1 model usedin the simulation. Note the specification allows for tolerance whereas the simulation models use thefixed values shown.
V

t2
t3

UA
0

0.1 Ustime

Us
0.9 Ustrtd
t1
aaa-033295

Fig. 2.

ISO 7637-2 test pulse wave shape

Table 1. Parameters for ISO 7637-2 pulse 1
Parameter
Nominal 12 V
12 V pulse model Nominal 24 V
systemsystem

24 V pulse modelUA

13.5 V ±0.5 V

13.5 V

27 V ±1 V

27 V

Us

−75 V to −150 V−75 V−300 V to −600 V−300 V

Ri

10 Ω

10 Ω

50 Ω

50 Ω

td

2 ms

2 ms

1 ms

1 ms

tr

1 +0/-0.5 μs

1 μs

3 μs

3 μs

t1

≥ 0.5 s0.5 s

≥ 0.5 s0.5 s

t2

200 mst3<100 μs

100 μs<100 μs

100 μst1 shall be chosen such that it is the minimum time for the DUT to be correctly initialized before
the application of the next pulse and shall be ≥ 0.5 s.
t3 is the smallest possible time necessary between the disconnection of the supply source andthe application of the pulse.

2.2. Simulating the conducted immunity transient - test setup
ISO 7637-2 goes into great detail of how to achieve the correct setup with the real world product,
particularly how to verify the open load test waveform from the test generator. In simulation thesituation is made easier in that the ISO transient source is configured to output the starting value ofthe battery voltage UA and then faithfully reproduces the remainder of the waveform.

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems

2.3. Artificial network
Using an artificial network as in Fig. 3 removes real life variation in the measurement result which
would otherwise occur from differences in vehicle wiring harness impedances. The network
therefore provides a standard reference laboratory environment for equipment to determine thebehaviour of electrical and electronic devices. In other words it is possible to test products at
different accredited test houses and expect reliably comparable results from each.

L

A

P

C
R

B

B

aaa-033289

Fig. 3.
••••

ISO 7637-2 artificial network

Inductor L = 5 µH
Internal resistance between terminals P and A < 5 mΩ
Capacitor C = 0.1 µF for working voltages of 200 VAC 1,500 VDCResistor R = 50 Ω

ISO 7637-2 indicates the frequency response of the network, where terminal A and B are shorted
together and the impedance is obtained looking into P with respect to B, see Fig. 4. In simulation
we can model the above response quite easily but having so many different real world circuit
configurations it is not possible to faithfully model all of them. In lieu the baseline simulation offers
an insight as to what happens to the MOSFET when the pulse appears inside the product.
aaa-033288

50| ZPB |
40

30

20

10

0
105

Fig. 4.

AN50007

application note

106

107

f (Hz)

108

ISO 7637-2 artificial network frequency response

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems

2.4. IAN50007 simulation 1: ISO 7637-2 Pulse 1 - 12 V
IAN50007 simulation 1 comprises ISO pulse generator, DUT with its corresponding thermal modeland an additional circuit used to verify the avalanche capability against data sheet specs. The ISO
generator outputs 500 pulses every 0.5 s. Its series resistance is set depending on the systembattery voltage, it is 10 Ω in case of a 12 V system and 50 Ω for a 24 V

Visit the IAN50007 interactive application note page to explore this simulation further.
Fig. 5.

IAN50007 simulation 1: ISO 7637-2 Pulse 1 - 12 V
The DUT is a series NMOS used to protect the load from reverse polarity conditions, feeding aparallel RC load. An ideal voltage generator is used to model a charge pump that would be neededin the actual application to correctly bias the gate of the MOSFET, ideally 10 V above the battery
rail voltage. Additionally a BJT has been used to turn OFF the MOSFET (by shorting its gate toground) when the reverse polarity condition is met.
The thermal model is used to monitor the variation in temperature of the junction. The ElectricalPower to Heat Flow block is used to convert the electrical power calculated as VDS × ID into heatflow that the thermal circuit will be able to handle. This block is also useful to directly monitor
the drain current and drain to source voltage of the MOSFET, simply by probing for I_sense and
V_sense, respectively. Notice how the ambient temperature is being set at 25 °C by using the
Thermal Ambient Reference block at the bottom of the RC network.
An additional RC network has been added to the NMOS Cauer model in order to take into accountthe PCB thermal behaviour (FR4). Finally an additional circuit is used to verify that the MOSFET
is operating within specification during avalanche. The avalanche test circuit is composed of an
inductor of 7 mH with a series resistance of 5 Ω. These two components are chosen in order toreplicate the conditions at which the MOSFET is subjected to when used in the ISO pulse circuit,during the avalanche event. The inductor is in fact charged at the same peak current of 6.7 A andthe drain voltage is set at 66.2 V. Only afterwards, the switch is opened and the energy stored in
the inductor is discharged through the MOSFET. The shape of the current and duration of the event
remain almost the same.
An external thermal network is employed to verify that the junction temperature in the two cases
reaches the same temperature, about 46 °C for a power peak of ~460 W.

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems

2.5. IAN50007 simulation 2: ISO 7637-2 Pulse 1 - 24 V

Visit the IAN50007 interactive application note page to explore this simulation further.
Fig. 6.

IAN50007 simulation 2: ISO 7637-2 Pulse 1 - 24 V
The BUK7Y4R8-60E is seen connected in series with the bulk electrolytic capacitance and internalloads. As the negative transient appears on the supply line the MOSFET remains enhanced for atime. This means the Gate pin with respect to its Source pin (VGS) remains positive and greaterthan its threshold voltage VGS(th).
During enhancement the MOSFET places a Drain to Source channel resistance (RDSon) in parallelwith its Source to Drain DIODE. Additionally the MOSFET allows Drain current to flow in either
direction through the channel resistance.
Energy stored in the bulk electrolytic capacitance can be drained by the negative-going pulse fromthe generator. Nexperia defines VGS(th) when 1 mA Drain current flows in the channel. VGS(th) has anegative temperature coefficient.
Since Electromagnetic Compliance Testing (EMC) is conducted in an ambient close to 25 °C weshould expect the threshold to be somewhere below 4 V as indicated in Fig. 7 below. Hence as thebattery supply becomes more negative at some point the charge pump will turn off and VGS will fall
below its VGS(th). The MOSFET enters its sub-threshold region (turns OFF).

Fig. 7.

BUK7Y4R8-60E data sheet VGS(th) characteristic
Nexperia guarantees the MOSFET to be in its sub-threshold region (DIODE mode) if VGS ≤ 1 V for
any temperature. The simulation uses a BJT to switch off the gate bias when VGS ≤ 1 V.

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems
003aah028

10-1
ID
(A)
10-2
typ

min

10-3

max

10-4

10-5

10-6

Fig. 8.

0

2

4

VGS (V)6BUK7Y4R8-60E sub-threshold

As the pulse continues in its negative direction the MOSFET, now behaving as a blocking DIODE,
will begin to leak appreciably when the negative bias across it reaches a voltage 10% greater thanthe MOSFETs rated VDS and by 30% will be in full avalanche.
The test requires 500 pulses to be applied. Each time the voltage across the device exceeds-1.3 × VDS rating, the MOSFET will be in avalanche. We have a choice either to ensure thecomponent can withstand the repetitive avalanche energy or prevent avalanche by fitting a TVS
suppressor across the product’s battery supply.
Note: an optional bidirectional TVS is shown. Dependent on budget and PCB real estate available
this may be two anti-series unidirectional types or one bidirectional as shown in Fig. 9.

-1.1 × VDS leakage current-1.3 × VDS avalanche current
Direction of current flow

S

D
G
≤1 V

UA
0V
Us

Internal to DUT

Reverse biased
body-diode

Bulk
Electrolytic
capacitance

Loads

Optional Transient
Voltage Suppression

aaa-033303

Fig. 9.

ISO 7637-2 Pulse 1 - potential to cause MOSFET avalanche

Note: from the above statement we have an expression for the avalanche breakdown voltage:
VBR ≈ 1.3 × V(BR)DSS. The negative sign in the description (not present in the above expression)is only to indicate that a negative bias is being applied to the anode with respect to the cathode tocause avalanche. Normally we consider the reverse bias case as a positive bias being applied tothe cathode with respect to the anode as shown in the graph of Fig. 10.

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems
VDS
VBR
V(BR)DSS
VDD

VDD

time

tAL

001aaj766

Fig. 10. Drain-source voltage, VDS•••

V(BR)DSS is the breakdown voltage when 250 µA leaks through the reverse biased diodeV(BR)DSS is stated in the data sheet for a particular device
VDD shown in Fig. 10 is the equivalent of system voltage UA.

The simulation shows the voltage, current and power dissipated by the MOSFET diode during thenegative transient event when connected as an RBP pass element as above. What is needed issome way to reliably replicate the exposure of the MOSFET to the energy normally seen in anavalanche event and decide whether the 500 ISO pulses can be considered as repetitive or single
events. Hence there are two circuits in the simulation one for the RBP above and the other for anavalanche (AKA Unclamped Inductive Switching or UIS) event.
The diagrams below show the anatomy of the UIS waveform. Note the controlled linear current
ramp produced by having an inductive load which helps to accurately describe the energy
dissipated by the MOSFET during the event.
VGS

VDS
VBR

ON

V(BR)DSS

OFF

VDD

VDD

time

001aaj765

tAL

Fig. 11. Gate-source voltage VGS

time
001aaj766

Fig. 12. Drain-source voltage VDSP
PDS(AL)MID

area in PDS(AL) triangle= avalanche energy(EDS(AL)S) dissipated

IDS(AL)S

tAL

time

tAL

001aaj767

Fig. 13. Drain current, ID

time001aaj768

Fig. 14. Peak drain-source avalanche power,
PDS(AL)M

Tj
Tj(max)Tj(max)
Tj

tAL

time
001aaj769

Fig. 15. Transient junction temperature profile of MOSFET during an avalanche event
Fig. 16 below shows how the single event above translates to repetitive UIS. As long as the energy
absorbed by the MOSFET remains within safe operating limits for one event the MOSFET is6
expected to survive > 100 x 10 avalanche events, refer to Fig. 17. Having only 500 ISO pulses
applied, the task here is to ensure the device can survive that first ISO pulse.

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems
aaa-031584

1010
No. Events

109

VBR
V(BR)DSS
IDS(AL)R

VDD

tAL

108

1

time
001aaj772

Fig. 16. Drain-source voltage, VDS andrepetitive drain-source avalanche
current, IDS(AL)R

10
EDS(AL) Per Event (mJ)102

Fig. 17. Repetitive avalanche rating;maximum number of avalanche
events as a function of avalancheenergyThe current profile of the 12 V UIS simulation has been modified with a 7 mH inductance suchthat the current peak, rise and fall times closely match that of the current profile of the 12 V
RBP MOSFET. The combinational graph shown in Fig. 18 (MOSFET waveforms) is taken fromsimulation for the RBP MOSFET and Fig. 19 (Avalanche current) is taken from the avalanche
analogy.

Voltage (V)

V

DS_Q1

Current (A)I D_Q1

Power (W)

P_Q1

aaa-033308

Fig. 18. ISO 7637-2 - 12 V Pulse 1 - MOSFET Q1 waveforms
I

AL_Q1

Current (A)IAL_Q2aaa-033309

Fig. 19. ISO 7637-2 - 12 V Pulse 1 - MOSFET Q1 and Q2 avalanche current waveforms

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems
T j_Q2Junction temperature (°C)

T j_Q1aaa-033310

Fig. 20. ISO 7637-2 - 12 V Pulse 1 - MOSFET Q1 and Q2 junction temperature waveforms
Curve (1) of Fig. 21 is the reference curve for safe operation of the BUK7Y4R8-60E for a single
event with a junction temperature Tj starting from 25 °C.
003aai641

103
IAL
(A)
102

6.7111 A

(1)

10

(2)

1
(3)

10-1
10-3

10-2

(1) T

j(init) = 25 °C(2) Tj(init) = 150 °C

10-1

1
500 µstAL (ms)

10(3) Repetitive avalanche

Fig. 21. BUK7Y4R8-60E avalanche rating; avalanche current as a function of avalanche
time

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AN50007

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems
Referring to Fig. 14, the peak drain-source avalanche power (PDS(AL)M) dissipated in the MOSFET
was shown to be the product of the breakdown voltage (VBR) and the non-repetitive drain-source
avalanche current (IDS(AL)S).

E DS(AL)S =PDS(AL)M × t AL
2

(1)

The avalanche simulation gives values for breakdown voltage, avalanche time and peak
breakdown current:•••

VBR = 1.3 * 60 = 78 V
tAL = 86.5016 - 86.5011 = 500 μs
Ipk = 6.7111498 A

Substituting these values in Eq.1 we obtain:
EDS(AL)S = (78 V * 6.7111498A * 500 µs) /2 = 130.87 mJ, which can be safely absorbed by the
MOSFET.
Adding coordinate lines for IAL = 6.7 A and tAL = 500 μs to the graph shown in Fig. 21 confirms weare well inside the safe operating area inscribed by curve (1).

Fig. 22. BUK7Y4R8-60E data sheet extract: EDS(ALS) and V(BR)DSS

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3. ISO 16750-2 section 4.6.4 load dump
Consider what would happen if for instance a vehicle were undergoing maintenance while theengine was running. The alternator is charging the battery and providing power for the vehicle andin good regulation holding the battery supply lines somewhere between 13.5 V to 14.5 V, typically
14.2 V for a nominal 12 V system.
An alternator’s output is controlled by the current flow in the field winding. The larger the fieldcurrent the greater the output current from the alternator. Stator and field windings have large
inductances so changes in field current to provide regulation follow a trend rather than a step.
Assume the battery is in a poor state of charge and providing a heavy load when it is disconnectedfrom the system. This loss of load (load dump) is a step change which happens much faster than
the regulator’s ability to reduce the current in the field winding. The energy available from thealternator at this time is much greater than the system requires.
B

RectifierTo Battery +DiodesStatorIG
Field Windings

Field Current
SupplyRotor

Slip rings

Ignition Switch
Regulator ON control

Brushes
Output Voltage Regulator(Field Current control)

S
Voltage Sense Terminal
Input from Battery +L

Alternator Case

Charge Light Control
aaa-033307

Fig. 23. Alternator function
The energy required from the alternator is the system power consumption for the time of thedemand, given by:
Energy = Power × time = Voltage × Current × time (measured in the derived Watt-second unit)
where 1 Ws = 1 Joule.
When the battery is disconnected, load current will drop by an amount, for the sake of simplicity
let’s imagine this amount to be half the present system current. Due to regulation latency at the
moment of disconnection the equality for our example becomes:

E = V × I × t = 2V × 0.5I × t(2)i.e. the decrease in load current is being compensated for by an increase in output voltage from thealternator and will persist until the field current is reduced by the regulator.

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems
In our simplified example above the implication is that the peak voltage appears as a step change
whereas in reality the rise in voltage is not instantaneous but rather limited by circuit dynamics. The
behaviour is better described by the wave shapes of the ISO16750-2 pulses which are based on
estimation from real life experience.
Some of the ISO transient pulses can be destructive. Load dump pulses are particularly goodcandidates to expose design weaknesses. An under-rated TVS will usually fail short circuit or very
low resistance but semiconductors have the potential to fail with some level of impairment otherthan a short circuit. A full short circuit or very low resistance failure can be viewed as beneficial
when performing DFMEA assessment as the failure is highly detectable at system level. An open
circuit or impaired TVS is much more difficult to assess.

3.1. Simulating test waveform ISO 16750-2 section 4.6.4 - test A
Systems which do not have a means of controlling output voltage from the alternator have tobe able to cope with unsuppressed load dump pulses. The amplitude of the test waveform issignificantly higher than the suppressed alternator voltage described in Test Pulse B.
td

U
tr
US
0.9 (US - U A ) + UA

0.1 (US - U A ) + UA
UA
0

time
aaa-033291

Key• U - test voltage• td - duration of pulse• tr - rising slope• UA - supply voltage for generator in operation• US - supply voltage
Fig. 24. ISO 16750-2 section 4.6.4 test A waveform – without centralized load dump
suppression
Table 2. Pulse for test A with 12 V and 24 V nominal voltage
Parameter
Type of system
Us (V) [1]79 ≤ US ≤ 101

151 ≤ US ≤ 202

0.5 ≤ Ri ≤ 4

1 ≤ Ri ≤ 8

td (ms)40 ≤ td ≤ 400

100 ≤ td ≤ 350

tr (ms)

10

10

[1]

application note

UN = 24 V(Ω)

Ri

AN50007

UN = 12 V[a]Minimum test
requirements
10 pulses at 1 min intervals

If not otherwise agreed; use the upper voltage level with the upper value for the internal resistance, or use
the lower voltage with the lower value for the internal resistance.

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AN50007

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems
The internal resistance, Ri, of the load dump test pulse generator can be obtained as follows:

Ri =10 × U nom × N act
0.8 × I rated × 12,000 min-1(3)

where:•••

Unom is the specified voltage of the alternator-1
rated is the specified current at an alternator speed of 6,000 min
Nact is the actual alternator speed, in reciprocal minutes

Simulations 3 and 4 comprise the ISO pulse generator and DUT with the corresponding thermal
model.
The ISO generator outputs 10 pulses with an interval of 60 s after the voltage returns to its nominal
system voltage value. Its series resistance is set depending on the system battery voltage, it is
0.5 Ω in case of a 12 V system and 1 Ω for a 24 V one.
The DUT is a series NMOS used to protect the load from reverse polarity conditions feeding aparallel RC load. An ideal voltage generator is used to model a charge pump that would be neededin the actual application to correctly bias the gate of the FET ideally 10 V above the battery rail
voltage.
The thermal model is used to indicate the variation in temperature of the junction. The ElectricalPower to Heat Flow block converts electrical power calculated as VDS·ID into heat flow that thethermal circuit will be able to handle. This block is also useful to directly monitor the drain current
and drain to source voltage of the FET, simply by probing for I_sense and V_sense, respectively.
Notice how the ambient temperature is being set at 25 °C by using the Thermal Ambient Reference
block at the bottom of the RC network. An additional RC network has been added to the NMOS
Cauer model in order to take into account the PCB thermal behaviour (FR4).
In the 12 V simulation dissipating a peak power of ~ 3.5 W, the FET junction temperature is
expected to rise to 25.35 °C.
In the 24 V simulation dissipating a peak power of ~ 3.5 W, the FET junction temperature is
expected to rise to 25.7 °C.

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems

3.2. IAN50007 simulation 3: ISO16750-2 - 12 V test A
In the 12 V simulation dissipating a peak power of ~ 3.5 W, the FET junction temperature is
expected to rise to 25.35 °C.

Visit the IAN50007 interactive application note page to explore this simulation further.
Fig. 25. IAN50007 simulation 3: ISO16750-2 - 12 V test A

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems

3.3. IAN50007 simulation 4: ISO16750-2 - 24 V test A
In the 24 V simulation dissipating a peak power of ~ 3.5 W, the FET junction temperature is
expected to rise to 25.7 °C.

Visit the IAN50007 interactive application note page to explore this simulation further.
Fig. 26. IAN50007 simulation 4: ISO16750-2 - 24 V test A

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems

4. Simulating test waveform ISO 16750-2 for section 4.6.4 - test B
The wave shape shown in Fig. 27 is for 12 V and 24 V systems which have Central Load Dump
Protection. This means that some form of extremely capable transient suppression is present within
the alternator to hold its output below a certain voltage. This is achieved by replacing the Recovery
Rectifiers of the three phase bridge with Zener Diodes.
The voltage waveform is very similar to that of the pulse for test A except the peak of the waveform
has been clipped due to the Zener function in the alternator’s output rectifier bridge.
If further suppression is needed to protect components inside the product then a suitably sized
Transient Voltage Suppressor (TVS) can be selected.
TVS devices function as very fast Zener diodes. The lower the breakdown voltage (VBR) chosen for
the TVS, the earlier in the transient waveform it will begin to conduct and the higher the dissipation
throughout the remainder of the pulse.
U

td
tr

US
0.9 (US - U A ) + UA

*US
0.1 (US - U A ) + UA
UA

0
time
aaa-033292

Key• U - test voltage• td - duration of pulse• tr - rising slope• UA - supply voltage for generator in operation• US - supply voltage
Fig. 27. ISO 16750-2 section 4.6.4 test B waveform – with centralized load dump
suppression
Table 3. Pulse for test B with 12 V and 24 V nominal voltage
Parameter
Type of system
UN = 12 V

UN = 24 V

Us[1] (V)79 ≤ US ≤ 101

151 ≤ US ≤ 202

Us[1] (V) (V)79 ≤ US ≤ 101

As specified bycustomer (typicalvalue 58 V)

Ri [1] (V) (Ω)

0.5 ≤ Ri ≤ 4

1 ≤ Ri ≤ 8

td (ms)40 ≤ td ≤ 400

100 ≤ td ≤ 350

t3 (ms)

10

10

[1]

AN50007

application note

Minimum test
requirements
5 pulses at 1 min intervals

If not otherwise agreed; use the upper voltage level with the upper value for the internal resistance, or use
the lower voltage with the lower value for the internal resistance.

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems
The simulations comprise the ISO pulse generator and DUT with the corresponding thermal model.
The ISO generator outputs 5 pulses with an interval of 60 s after the voltage returns to its nominal
system voltage value. Its series resistance is set depending on the system battery voltage, it is
0.5 Ω in case of a 12 V system and 1 Ω for a 24 V one.
The DUT is a series NMOS used to protect the load from reverse polarity conditions feeding aparallel RC load. An ideal voltage generator is used to model a charge pump that would be neededin the actual application to correctly bias the gate of the FET ideally 10 V above the battery rail
voltage. The thermal model is used to indicate the variation in temperature of the junction. The
Electrical Power to Heat Flow block converts electrical power calculated as VDS·ID into heat flowthat the thermal circuit will be able to handle. This block is also useful to directly monitor thedrain current and drain to source voltage of the FET, simply by probing for I_sense and V_sense,
respectively.
Notice how the ambient temperature is being set at 25 °C by using the Thermal Ambient Reference
block at the bottom of the RC network. An additional RC network has been added to the NMOS
Cauer model in order to take into account the PCB thermal behaviour (FR4).

4.1. IAN50007 simulation 5: ISO16750-2 - 12 V test B
In the 12 V simulation dissipating a peak power of ~ 3.5 W, the FET junction temperature is
expected to rise to 27.90 °C.

Visit the IAN50007 interactive application note page to explore this simulation further.
Fig. 28. IAN50007 simulation 5: ISO16750-2 - 12 V test B

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4.2. IAN50007 simulation 6: ISO16750-2 - 24 V test B
In the 24 V simulation dissipating a peak power of ~ 3.5 W, the FET junction temperature is
expected to rise to 25.7 °C.

Visit the IAN50007 interactive application note page to explore this simulation further.
Fig. 29. IAN50007 simulation 6: ISO16750-2 - 24 V test B

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5. Vehicle Electrification Definitions
There are four mainstream categories of vehicles undergoing some form of electrification: Battery
Electric Vehicle (BEV); Hybrid Electric Vehicle (HEV); Plug-in Hybrid Electric Vehicle (PHEV) and
Mild Hybrid. The capability of electric motors to propel the vehicle independently of the Internal
Combustion Engine (ICE) differs with the hybrid vehicle type. Nomenclature for battery chargers
may vary from country to country but in general classifications are: Level 1 (L1), Level 2 (L2) and
DC Fast Charger (DCFC), each in increasing power capability respectively. L1 and L2 are normallyto be found at residential properties. In the UK the residential chargers would be classified as
Type1 (slow typically <3 kW fully charged in 8-10 hours) or Type 2 (fast typically 7 kW or 22 kW
fully charged in 2-4 hours).
As vehicle charging technologies improve and high power charging stations of typically 43 kW
become more widely availability then charging times will reduce to 30-60 minutes which is no more
an imposition than stopping for a break at a motorway service facility.

AN50007

application note•

Battery Electric Vehicles (BEVs)
The sole source of energy is provided by battery systems and dependent on vehicle
efficiencies. Propulsion for passenger vehicles is provided by three phase induction motors
fed from a high voltage (HV) battery system, commonly in the range 360 V to 450 V, - althoughhigher voltage systems are available. The motors are AC machines. Inverters are required toconvert from battery DC to construct the AC waveform. In automotive applications the motor
has to be able to rotate at varying speeds and torque. The PWM control features available fromthe inverter make such variable speed control possible.
A 12 V battery is used to provide low tension auxiliary power e.g. for low 5V/12V power outlets,
multimedia and lighting.
1 kWh taken from the mains supply will provide approximately 4 miles of range with these HV
motors. Balancing the range of electric vehicles between charges with performance has always
been the issue. Improvements in battery technologies and charge station availability away fromthe residential setting are addressing these key factors. e.g. at the time of writing dependent onmaker, model and driving style, fast-charge electric vehicle ranges vary from 110 to 373 miles.

•

Hybrid Electric Vehicles (HEVs)
HEVs have ICE and electric motive power. Electrical propulsion for passenger vehicles
is provided by three phase induction motors fed from a high voltage (HV) battery systemcommonly in the range 360 V to 450 V. Higher voltage systems can be found. HEVs
can recharge their battery through generators driven from the ICE including overrun andrecuperative (regenerative) braking. Dependent on load an HEV can travel for short distancesof 1 to 2 miles before resorting to the ICE to provide propulsion and recharge the depleted
battery. Dependent on the battery charge state, electric motors can propel the HEV from astanding start. The acceleration is smooth reaching speeds of 30 m.p.h. with seemingly little
effort. If a more prolonged acceleration is required the ICE is switched into the powertrain toprovide propulsion and recharging of the battery. The ICE is employed at cruising speeds when
it can operate most efficiently. A 12 V battery is present to provide low tension auxiliary powere.g. low 5 V/12 V power outlets, multimedia and lighting.

•Plug-in Hybrid Electric Vehicles (PHEVs)
PHEVs behave similarly to HEVs having both ICE and motors which are capable of providing
electric motive power in isolation to the ICE. Electrical propulsion for passenger vehicles
is provided by three phase induction motors fed from a high voltage (HV) battery systemcommonly in the range 360V to 450 V, although higher voltage systems can be found. PHEVs
can recharge their battery through generators driven by the ICE including overrun andrecuperative (regenerative) braking. PHEVs have a greater battery capacity than HEVs andas the name states the PHEV’s battery is plug-in mains rechargeable. The increased battery
capacity permits the PHEV to travel for longer periods on electric power before resorting to
the ICE with ranges of 10 to 40 miles being common. A 12 V battery is present to provide low
tension auxiliary power e.g. low 5 V/12 V power outlets, multimedia and lighting.

•

Mild hybrid (48 V systems)
In mild hybrid solutions where a conventional 12 V battery system with ICE is supported by aStarter/Generator and DC/DC converter interfaces to the 48 V battery. Electric motors are used
to assist the ICE during acceleration and cruising but the motor is unable to power the vehicle inisolation.

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems

2

1

3

6

4

Main 48-Volt additions

5

1 Electric starter generator - initially mounted on the belt of the engine (belt starter generator (BSG))
2 AC/DC converter - changes the current flowing from and to the starter generator
3 48-volt lithium ion battery (includes battery controller for regulation) - provides additional power to handle
the power hungry applications
4 DC/DC converter - the bridge between the new 48-volt system and the existent 12-volt one
5 12-volt lead acid battery - the good, old battery used for engine cold start and established 12-volt system
6 Electrical supercharger - eliminates the turbo lag limitation of the conventional turbocharger andaaa-027607
provides boost to the engine

6. 48 V powertrain development
To improve efficiencies further and continue to reduce the vehicle’s C02 footprint alternatives to the48 V on-engine 5 kW, 85% efficient BSG are required:••••P1 on-engine, higher torque, no belt losses, 10 kW, 94% efficientP2 gearbox input shaft either integral or side attached along with the decoupler allows forelectrically assisted drive and energy recuperation
P3 gearbox output shaft, similar to the benefits of the P2 position
P4 rear axle and the decoupler systems allow for an electrically assisted all wheel drive
configuration, 21 kW, 95% efficientFig. 30. 48 V powertrain

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems

6.1. Requirement for 48 V battery systems
The adverse effects of global warming are becoming more noticeable. In many cases what wasconsidered a 1 in 100 year climatic event is being repeated within a 10 year period. Scientificrecommendation is to maintain average global temperatures ≤1.5 °C those of the preindustrial
period by removing carbon pollution from the atmosphere. The Automotive industry lends its
support for improvement by investing billions in battery electric vehicles (BEV) and a variety ofhybrid vehicle types. OEMs are now committed to electrification, some of whom target to havemade the leap away from internal combustion engine (ICE) passenger vehicles well in advance of2030 where electric vehicles are expected to meet 50% of all passenger vehicle demand.
The new vehicles have to offer efficiencies over the established ICE solutions. One problem with
12 V systems is the copper loss of the vehicle harness. 48 V battery systems use less current for agiven power demand. The greater the number of high power vehicle functions which can be moved
onto the 48 V battery system the more efficient the vehicle becomes.
2Power loss = Load Current × Harness Resistancee.g. Compare current demand for a 240 W load:••

48 V systems require 240 W/48 V = 5 A
12 V systems require 240 W/12 V = 20 A.
2

Although the 48 V system requires 5 A/20 A = 1/4 of the 12 V system current, in terms of I R
2
conduction losses this is hugely beneficial such that the 48 V system suffers a loss of only (5 *R)/2
2
(20 *R)=(5 A/20 A) =1/16 that of the 12 V system.
In other words for a given power consumption, for every Watt of heat lost in the 12 V harness we
can expect only 0.0625 W to be lost in the 48 V harness for the same wire size.
Since wire resistance is given by:
Resistance=(Resistivity*wire length)/ Conductor Cross-Sectional Area
R=(ρ*L)/A
As the move to 48 V brings such significant reductions in losses, OEMs have the freedom tochoose the balance between cost efficiency using conductors of smaller cross-sectional area
(higher resistance per unit length) and increased harness loss.

6.2. Transient pulse descriptions for 48 V battery systems
It is important to note from these new solutions that the complexity of the vehicle’s electrical system
is increasing. Having 12 V and 48 V battery systems on board means having the flexibility to shareenergy between them to keep the charge state of each battery healthy.
Unfortunately this complexity also means the types and number of equipment able to createtransient perturbation on a battery supply has also increased.
ISO 21780: 2020 contains statements to the effect that 48V equipment interfacing to 12 V systems
to meet the specified transient immunity and emission requirements of both.
The 48 V battery is not intended to be directly accessible as is the case for the 12 V/24 V batteries
hence there are no requirements for negative battery supply line transients in ISO 21780: 2020.

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems

6.3. ISO 21780: 2020 short term overvoltage
The test is intended to verify the immunity of the product to the transient over-voltages given in
Table 4.
U
U1

U2

U0

0
t0

tr

t1

tf

t2

tf

time

t3

aaa-033293

Fig. 31. Test profile for ISO 21780: 2020 test-03: short term overvoltage
Table 4. Test parameters for ISO 21780: 2020 test-03: short term overvoltage
Operating mode
2.4

AN50007

application note

U0

52 V

U1

70 V

U2

58 V

t0

≥5s

tr

0.7 ms (2,571 V/ms)

t1

40 ms

tf

1 ms

t2

600 mst3≥5 s

Number of cycles

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems

6.3.1. IAN50007 simulation 7: ISO21780: 2020 test-03

Visit the IAN50007 interactive application note page to explore this simulation further.
Fig. 32. IAN50007 simulation 7: ISO21780: 2020 test-03

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems

6.4. ISO 21780: 2020 load dump
Similarly to the 12 V/24 V systems this test simulates voltage transients that occur when there isa sudden reduction in the load current drawn. When considering the load dump source for ISO
16750-2 in Section 3 for those 12 V and 24 V systems the alternator was considered the candidate
for transient generation. In the 48 V system the specification makes references to generator, motorgenerator or DC/DC converter and the battery being either in-circuit unable to absorb power or outof circuit altogether.
S1

U 48

DUT

C

GND 48R

1tf

S1 switch on 48 V
R

resistor simulating vehicle power network resistanceCcapacitor simulating vehicle power network capacitance1

test load

aaa-033305

Fig. 33. Test setup for test-04: load dump
Table 5. Test parameters for test-04: load dump
Operating mode
2.4

AN50007

application note

U0

52 V

R

36 Ω

C

0.5 mF

tS1≤ 100 µs

Number of cycles

2

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems
U
U1

U2

U0

tr

t1

tf

t2

tf

t3

time
aaa-033306

Fig. 34. Test profile for test-04: load dump
Table 6. Requirement parameters for test-04: load dump

AN50007

application note

Operating mode

2.4

U1

70 V

U2

58 V

t1

40 ms

t2

600 mst3

9s

tr

0.7 mstf

1 ms

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems

6.5. IAN50007 simulation 8: ISO 21780 - 48 V test 04

Visit the IAN50007 interactive application note page to explore this simulation further.
Fig. 35. IAN50007 simulation 8: ISO 21780 - 48 V test 04

7. Summary
Only five of the many battery line transients have been discussed and simulated for 12 V, 24 V and
48 V battery systems although the one’s chosen are some of the most troublesome in terms of thepotential to cause damage to the product. Creating an accurate simulation model and following up
with diligent iterative bench work helps improve both product and simulation reducing the likelihoodof costly failures at key stages of the product development process.
The focus has been on MOSFETs performing the RBP function, where, the forward biased antiparallel diode provides a protective envelope across the Source-Drain channel when positive goingbattery transients are present. The situation becomes complicated where an additional MOSFET
connected in series with the RBP MOSFET is acting as a switch. Here the MOSFET is connectedwith its Drain-Source connections reversed. The MOSFET has to have a VDS rating sufficient tosurvive the largest transient impressed across it and runs the risk of avalanche. When the devices
begins to turn ON it operates in linear mode so capacitor inrush current can pose a problem.
Care must be taken to ensure both RBP and switch MOSFETs are properly enhanced when large
currents are being demanded by the load.
Guidance has been provided to clarify that negative transients can cause avalanche in RBP and
how to design for this mode of operation. Nexperia offers a large amount of technical material on
the web to support engineers with sound design practices for their applications.
The interactive application note web page IAN50007 includes SystemVision® embedded Cloudsimulations as discussed in this application note.

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems

8. Revision history
Table 7. Revision history
Revision
Date
numberDescription

1.0

Initial version.

2021-04-08

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems

9. Legal information
Definitions
Draft — The document is a draft version only. The content is still underinternal review and subject to formal approval, which may result in
modifications or additions. Nexperia does not give any representations or
warranties as to the accuracy or completeness of information included hereinand shall have no liability for the consequences of use of such information.

Disclaimers
Limited warranty and liability — Information in this document is believed
to be accurate and reliable. However, Nexperia does not give any
representations or warranties, expressed or implied, as to the accuracy
or completeness of such information and shall have no liability for theconsequences of use of such information. Nexperia takes no responsibility
for the content in this document if provided by an information source outsideof Nexperia.
In no event shall Nexperia be liable for any indirect, incidental, punitive,
special or consequential damages (including - without limitation - lost
profits, lost savings, business interruption, costs related to the removalor replacement of any products or rework charges) whether or not suchdamages are based on tort (including negligence), warranty, breach ofcontract or any other legal theory.
Notwithstanding any damages that customer might incur for any reason
whatsoever, Nexperia’s aggregate and cumulative liability towards customer
for the products described herein shall be limited in accordance with theTerms and conditions of commercial sale of Nexperia.
Right to make changes — Nexperia reserves the right to make changes
to information published in this document, including without limitation
specifications and product descriptions, at any time and without notice. This
document supersedes and replaces all information supplied prior to the
publication hereof.
Suitability for use — Nexperia products are not designed, authorized or
warranted to be suitable for use in life support, life-critical or safety-criticalsystems or equipment, nor in applications where failure or malfunctionof an Nexperia product can reasonably be expected to result in personal
injury, death or severe property or environmental damage. Nexperia and its
suppliers accept no liability for inclusion and/or use of Nexperia products insuch equipment or applications and therefore such inclusion and/or use is at
the customer’s own risk.
Applications — Applications that are described herein for any of theseproducts are for illustrative purposes only. Nexperia makes no representation
or warranty that such applications will be suitable for the specified use
without further testing or modification.
Customers are responsible for the design and operation of their applications
and products using Nexperia products, and Nexperia accepts no liability forany assistance with applications or customer product design. It is customer’ssole responsibility to determine whether the Nexperia product is suitableand fit for the customer’s applications and products planned, as well as
for the planned application and use of customer’s third party customer(s).
Customers should provide appropriate design and operating safeguards tominimize the risks associated with their applications and products.
Nexperia does not accept any liability related to any default, damage, costs
or problem which is based on any weakness or default in the customer’s
applications or products, or the application or use by customer’s third party
customer(s). Customer is responsible for doing all necessary testing for thecustomer’s applications and products using Nexperia products in order toavoid a default of the applications and the products or of the application or
use by customer’s third party customer(s). Nexperia does not accept any
liability in this respect.
Export control — This document as well as the item(s) described herein
may be subject to export control regulations. Export might require a priorauthorization from competent authorities.
Translations — A non-English (translated) version of a document is forreference only. The English version shall prevail in case of any discrepancy
between the translated and English versions.

Trademarks
Notice: All referenced brands, product names, service names andtrademarks are the property of their respective owners.

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems

List of Tables
Table 1. Parameters for ISO 7637-2 pulse 1....................... 4
Table 2. Pulse for test A with 12 V and 24 V nominal
voltage................................................................................ 14
Table 3. Pulse for test B with 12 V and 24 V nominal
voltage................................................................................ 18
Table 4. Test parameters for ISO 21780: 2020 test-03:
short term overvoltage....................................................... 24
Table 5. Test parameters for test-04: load dump................26
Table 6. Requirement parameters for test-04: load dump.. 27
Table 7. Revision history....................................................29

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems
Fig. 31. Test profile for ISO 21780: 2020 test-03: shortterm overvoltage................................................................ 24

List of Figures
Fig. 1. Circuit diagram that can produce ISO 7637-2
pulse 1..................................................................................3
Fig. 2. ISO 7637-2 test pulse wave shape...........................4
Fig. 3. ISO 7637-2 artificial network.....................................5

Fig. 32. IAN50007 simulation 7: ISO21780: 2020 test-03.. 25
Fig. 33. Test setup for test-04: load dump......................... 26
Fig. 34. Test profile for test-04: load dump........................ 27
Fig. 35. IAN50007 simulation 8: ISO 21780 - 48 V test 04.28

Fig. 4. ISO 7637-2 artificial network frequency response.....5
Fig. 5. IAN50007 simulation 1: ISO 7637-2 Pulse 1 12 V......................................................................................6
Fig. 6. IAN50007 simulation 2: ISO 7637-2 Pulse 1 24 V......................................................................................7
Fig. 7. BUK7Y4R8-60E data sheet VGS(th) characteristic.. 7
Fig. 8. BUK7Y4R8-60E sub-threshold................................. 8
Fig. 9. ISO 7637-2 Pulse 1 - potential to cause
MOSFET avalanche............................................................. 8
Fig. 10. Drain-source voltage, VDS..................................... 9
Fig. 11. Gate-source voltage VGS....................................... 9
Fig. 12. Drain-source voltage VDS...................................... 9
Fig. 13. Drain current, ID..................................................... 9
Fig. 14. Peak drain-source avalanche power, PDS(AL)M.... 9
Fig. 15. Transient junction temperature profile of
MOSFET during an avalanche event...................................9
Fig. 16. Drain-source voltage, VDS and repetitive
drain-source avalanche current, IDS(AL)R........................ 10
Fig. 17. Repetitive avalanche rating; maximum
number of avalanche events as a function ofavalanche energy...............................................................10
Fig. 18. ISO 7637-2 - 12 V Pulse 1 - MOSFET Q1
waveforms.......................................................................... 10
Fig. 19. ISO 7637-2 - 12 V Pulse 1 - MOSFET Q1 andQ2 avalanche current waveforms...................................... 10
Fig. 20. ISO 7637-2 - 12 V Pulse 1 - MOSFET Q1 andQ2 junction temperature waveforms.................................. 11
Fig. 21. BUK7Y4R8-60E avalanche rating; avalanche
current as a function of avalanche time.............................11
Fig. 22. BUK7Y4R8-60E data sheet extract:
EDS(ALS) and V(BR)DSS................................................. 12
Fig. 23. Alternator function.................................................13
Fig. 24. ISO 16750-2 section 4.6.4 test A waveform –without centralized load dump suppression....................... 14
Fig. 25. IAN50007 simulation 3: ISO16750-2 - 12 V
test A.................................................................................. 16
Fig. 26. IAN50007 simulation 4: ISO16750-2 - 24 V
test A.................................................................................. 17
Fig. 27. ISO 16750-2 section 4.6.4 test B waveform –with centralized load dump suppression............................ 18
Fig. 28. IAN50007 simulation 5: ISO16750-2 - 12 V
test B.................................................................................. 19
Fig. 29. IAN50007 simulation 6: ISO16750-2 - 24 V
test B.................................................................................. 20
Fig. 30. 48 V powertrain.....................................................22

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Applying ISO standard conducted transients to MOSFETs in 12 V, 24 V and 48 V systems

Contents
1. Introduction................................................................... 2
2. ISO 7637-2 pulse 1....................................................... 3
2.1. Simulating the conducted immunity transient test waveform.......................................................................4
2.2. Simulating the conducted immunity transient test setup..............................................................................4
2.3. Artificial network.......................................................... 5
2.4. IAN50007 simulation 1: ISO 7637-2 Pulse 1 - 12 V..... 6
2.5. IAN50007 simulation 2: ISO 7637-2 Pulse 1 - 24 V..... 7
3. ISO 16750-2 section 4.6.4 load dump........................133.1. Simulating test waveform ISO 16750-2 section
4.6.4 - test A...................................................................... 14
3.2. IAN50007 simulation 3: ISO16750-2 - 12 V test A..... 16
3.3. IAN50007 simulation 4: ISO16750-2 - 24 V test A..... 17
4. Simulating test waveform ISO 16750-2 forsection 4.6.4 - test B........................................................18
4.1. IAN50007 simulation 5: ISO16750-2 - 12 V test B..... 19
4.2. IAN50007 simulation 6: ISO16750-2 - 24 V test B..... 20
5. Vehicle Electrification Definitions............................. 21
6. 48 V powertrain development....................................226.1. Requirement for 48 V battery systems...................... 23
6.2. Transient pulse descriptions for 48 V battery
systems.............................................................................. 23
6.3. ISO 21780: 2020 short term overvoltage................... 24
6.3.1. IAN50007 simulation 7: ISO21780: 2020 test-03.... 25
6.4. ISO 21780: 2020 load dump..................................... 26
6.5. IAN50007 simulation 8: ISO 21780 - 48 V test 04......28
7. Summary..................................................................... 28
8. Revision history..........................................................29
9. Legal information........................................................30© Nexperia B.V. 2021. All rights reserved

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Date of release: 8 April 2021

AN50007

application note

All information provided in this document is subject to legal disclaimers.

Rev. 1.0 — 8 April 2021

© Nexperia B.V. 2021. All rights reserved

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