ACS37612
Coreless, High Precision, Hall-Effect Current Sensor IC
with Common-Mode Field Rejection and High Bandwidth (240 kHz)FEATURES AND BENEFITSDESCRIPTION• Eliminates need for concentrator core or shield• Suited for applications where current flows throughbusbar or PCB• Very wide sensing range (2.5 to 20 mV/G)□ Ideal for sensing currents from <200 A to >1000 A• Factory-programmed segmented linear temperaturecompensation (TC) provides low thermal drift□ Sensitivity ±1% (typ)□ Offset ±3 mV (typ)• Differential Hall sensing rejects common-mode
magnetic fields• High operating bandwidth: DC to 240 kHz• AEC-Q100 Grade 0, automotive qualified• Contactless, lossless, non-invasive current sensing• Very fast response time (<2 μs typ)• 3.3 or 5.0 V single supply operation• Ratiometric output with unidirectional andbidirectional modes• Immune to mechanical stress• Monolithic Hall IC for high reliability• Wide ambient temperature range: –40°C to 150°C• Surface mount, small footprint, low-profile
TSSOP8 package

The Allegro ACS37612 current sensor IC enables low-cost
solutions for AC and DC current sensing without the need foran external field concentrator core or shield. It is designed for
applications where hundreds of amps flow through a busbar
or PCB.

PACKAGE:

8-pin TSSOP package (suffix LU)

Not to scale

Figure 1: Current Through PCB
ACS37612-DS, Rev. 2
MCO-0000792

Current flowing through a busbar or PCB trace generates amagnetic field that is sensed by the monolithic, low-offset,
linear Hall IC. The differential sensing topology virtuallyeliminates all types of errors due to common-mode straymagnetic fields. High isolation is achieved via the no-contact
nature of this simple assembly.
The ACS37612 is offered in 120 kHz and 240 kHz bandwidth
options, making it ideal for inverter phase current sensing,load detection and management, power supplies, and DC/
DC converters where fast switching is required. The fast
response time enables overcurrent fault detection in safetycritical applications. A –40°C to 150°C ambient operating
temperature range and a stellar ESD rating make it ready forharsh automotive environments.
The ACS37612 is suitable for space-constrained applications
because of its low-profile 8-pin surface mount TSSOP package(thin-shrink small outline package, suffix LU) that is lead (Pb)free, with 100% matte tin leadframe plating.

TYPICAL APPLICATIONS

•
•
•
•
•
•
•
•

High voltage traction motor inverter
48 V / 12 V auxiliary inverter
Battery monitoring
Overcurrent detection
DC/DC converter
Smart fuse
Power distribution unit (PDU)
Power supply

Figure 2: Current Through Busbar
December 10, 2021

Coreless, High Precision, Hall-Effect Current Sensor IC

ACS37612with Common-Mode Field Rejection and High Bandwidth (240 kHz)SELECTION GUIDEPart Number

Nominal Supply
Voltage (V)Differential
Magnetic
Input Range, (G)Sensitivity
Sens (Typ.)(mV/G) [1]

ACS37612LLUATR-010B3

3.3

±135

10

ACS37612LLUATR-005B5

5

±400

5

ACS37612LLUATR-010B5

5

±200

10

ACS37612LLUATR-010B5-C

5

±200

10

ACS37612LLUATR-015B5

5

±130

15

ACS37612LLUATR-015U5

5

0 to 26515

Bandwidth
(kHz)

TA
(°C)

Packing [2]120–40 to 150

4000 pieces per 13-inch reel[1] Measured at nominal supply voltage. Contact Allegro for other sensitivity options.
[2] Contact Allegro for additional packing options.

ACS

37612 L LUA

TR - 010 B

3Clamps:[blank] – Default, Clamps disabled
C – Clamps enabled
Bandwidth:[blank] – Default, BW = 120 kHz
H – High, BW = 240 kHz
Supply Voltage:
5 – VCC = 5 V
3 – VCC = 3.3 V
Output Directionality:
B – Bidirectional (positive and negative current)
U – Unidirectional (only positive current)
Typical Sensitivity (mV/G)
Packing Designator
Package Designator
Operating Temperature Range
5-Digit Part Number
Allegro Current Sensor

Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com

2

ACS37612

Coreless, High Precision, Hall-Effect Current Sensor IC

with Common-Mode Field Rejection and High Bandwidth (240 kHz)ABSOLUTE MAXIMUM RATINGS
Characteristic

SymbolNotes

Rating

Unit

Supply Voltage

VCC

6.5

V

Reverse Supply Voltage

VRCC

–0.5

V

Output Voltage

VOUT

6.5

V

Reverse Output Voltage

VROUT

–0.5

V

Output Source Current

IOUT(Source)

VOUT to GND

3mA

Output Sink Current

IOUT(Sink)

Minimum pull-up resistor of 500 Ω

10mA–40 to 150°C

TJ(max)

165

°C

Tstg

–65 to 165°C

Nominal Operating Ambient
Temperature
Maximum Junction Temperature
Storage TemperatureTA

Range LESD RATINGS
Value

Unit

Human Body Model

Characteristic

SymbolVHBM

Per AEC-Q100

Test Conditions

±12

kV

Charged Device Model

VCDM

Per AEC-Q100±1kV

THERMAL CHARACTERISTICS: May require derating at maximum conditions; see application information
Characteristic
Package Thermal Resistance

SymbolTest Conditions [1]

Value

Unit

RθJA

LU package, on 4-layer PCB based on JEDEC standard

145

°C/W

[1] Additional thermal information available on the Allegro website.

Figure 3: Allowable Power Dissipation

Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com

3

ACS37612

Coreless, High Precision, Hall-Effect Current Sensor IC

with Common-Mode Field Rejection and High Bandwidth (240 kHz)

VCC
VOUT

VOUT

VCC
CBYPASSCL
1-10 µF

0.1 µF

ACS37612
GND

Figure 4: Typical Application Circuit
The ACS37612 outputs an analog signal, VOUT, that varies linearlywith the bi-directional AC or DC field sensed within the range
specified. CL is for optimal noise management, with values that
depend on the application.

VOUT 1

8 NC

GND 2

7 NC

NC 3

6 NC

VCC 4

5 NC

Figure 5: Pinout Diagram

Pinout List
NumberName

Description

1

VOUT

Analog output signal, also used for programming

2

GND

Ground pin

3, 5, 6, 7, 8NC

Not connect; tie to GND for optimal ESD performance

4

VCC

Input power supply, also used for programming

Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com

4Coreless, High Precision, Hall-Effect Current Sensor IC

ACS37612

VCC

with Common-Mode Field Rejection and High Bandwidth (240 kHz)ACS37612

To all subcircuits

BypassTemperature
SensorUnder Voltage
Detec�on [1]Power On
Reset

Charge Pump
Pulse generator
Serial I/O
Control

EEPROM andControl Logic

Hall current
drive

Oﬀset
Control

Dynamic Oﬀset
Cancella�on

Sensi�vity
Control

OutputClampsVOUT

Signal recovery

L

Push/Pull
Output driver

GND
Analog signal path

Digital control

Digital blocks

Figure 6: Functional Block Diagram

Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com

5Coreless, High Precision, Hall-Effect Current Sensor IC

ACS37612with Common-Mode Field Rejection and High Bandwidth (240 kHz)COMMON OPERATING CHARACTERISTICS: Valid through full range of TA and VCC, unless otherwise specified
Characteristic

SymbolTest Conditions

Min.

Typ.

Max.

Unit

5 V nominal supply voltage variant

4.5

5

5.5

V

3.3 V nominal supply voltage variant

3

3.3

3.6

V

–

12

16

mA

ELECTRICAL CHARACTERISTICS
Supply Voltage

VCC

Supply Current

ICC

VCC(min) ≤ VCC ≤ VCC(max), where VCC = 5 V or 3.3 V,
no load on output

Power-On TimetPO

TA = 25°C

–

70

–

µs

Temperature Compensation
Power-On TimetTC

TA = 25°C, CL (of test probe) = 10 pF, CBYPASS = open

–

45

–

µs

VUVLOD

VCC rising; UVLO is disabled, enabling the device
output; TA = 25°C

–

3.8

4.2

V

VUVLOEVCC falling; UVLO is enabled, disabling the device
output; TA = 25°C

3.45

3.7

–

V

TA = 25°C

–

100

–

mV

tUVLOETime measured from falling VCC < VUVLOE toUVLO enabled; TA = 25°C

–

74

–

µs

tUVLODTime measured from rising VCC > VUVLOD toUVLO disabled; TA = 25°C

–

7

–

µs

tPORD

TA = 25°C, 3.3 V part variant only

–

7

–

µs

VPORH

TA = 25°C, VCC rising

–

2.8

–

V

VPORL

TA = 25°C, VCC falling

–

2.5

–

V

tPORR

TA = 25°C, VCC rising

–

64

–

µs

–

250

–

mV

Small signal –3 dB, CL = 1 nF, device programmed tolowest bandwidth mode (default)

–

120

–

kHz

Small signal –3 dB, CL = 1 nF, device programmed tohighest bandwidth mode

–

240

–

kHz

BWi = 240 kHz

–

1.7

–

µs

BWi = 120 kHz

–

3.2

–

µs

BWi = 240 kHz

–

1

–

µs

BWi = 120 kHz

–

1.5

–

µs

BWi = 240 kHz

–

1.6

–

µs

BWi = 120 kHz

–

3.2

–

µs

–

<1

–

Ω

Undervoltage Lockout (UVLO)
Threshold [1]UVLO Hysteresis
UVLO Enable/Disable
Delay TimePower-On Release Delay
Power-On Reset Voltage
Power-On Reset Release TimePower-On Reset Hysteresis
Internal Bandwidth

Rise Time [2]Propagation Delay [2]Response Time [2]VUVLO(HYS)

VHys(POR)
BWi

tr
tPD
tRESPONSE

TA = 25°C, CL = 1 nF
TA = 25°C, CL = 1 nF
TA = 25°C, CL = 1 nF

DC Output Impedance

ROUT

Output Load Resistance

RL

VOUT to GND

4.7

10

–

kΩ

Output Load Capacitance

CL

VOUT to GND

–

1

10

nF

Output Voltage Clamp(Clamp Enable Option Only)

VCLP(HIGH)TA = 25°C, RL(PULLDWN) = 10 kΩ to GND

0.9 × VCC––V

VCLP(LOW)

TA = 25°C, RL(PULLUP) = 10 kΩ to VCC––

0.1 × VCC

V

TA = 25°C; CL = 1nF; Step from 75% output range to
150%

–

5

–

µs

Delay to Clamp(Clamp Enable Option Only)
Output Saturation Voltage(Clamp Disabled Option Only)tCLP
VSAT(HIGH)TA = 25°C, RL(PULLDWN) = 10 kΩ to GND

VCC – 0.2––

V

VSAT(LOW)

TA = 25°C, RL(PULLUP) = 10 kΩ to VCC

–

–

200

mV

Continued on the next page…
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com

6Coreless, High Precision, Hall-Effect Current Sensor IC

ACS37612with Common-Mode Field Rejection and High Bandwidth (240 kHz)COMMON OPERATING CHARACTERISTICS (continued): Valid through full range of TA and VCC, unless otherwise specified
Characteristic

SymbolTest Conditions

Min.

Typ.

Max.

Unit

Bidirectional variant, no magnetic field,
TA = 25°C; VOUT(Q) ratiometric to VCC–

0.5 × VCC–

V

Unidirectional variant, no magnetic field,
TA = 25°C; VOUT(Q) ratiometric to VCC–

0.1 × VCC–V

VCC = ±5% variation of nominal supply voltage

–

±1.0

–

%

QUIESCENT OUTPUT VOLTAGE (V OUT(Q))
Quiescent Output Voltage

VOUT(Q)ERROR COMPONENTS
Clamp Ratiometry Error

RatERRCLP

Noise

BN

TA = 25°C, CL = 1 nF

–

2

–

mGRMS
/√(Hz)

Nonlinearity

ELIN

Up to full-scale output

–1

±0.45

1

%

Measured at 100 G uniform magnetic field

–

40

–

dB

Common Mode Field
Rejection Ratio

CMFRR[1] UVLO feature is available on parts with 5 V nominal supply voltage.

[2] Timing specified does not include potential effect of skin effect on conductor; value will depend on busbar/PCB design.

ACS37612LLUATR-005B5 PERFORMANCE CHARACTERISTICS: Valid over full range of TA and VCC = 5 V, unless otherwise specified
Characteristic

SymbolTest Conditions

Min.

Typ. [1]

Max.

Unit

–400

–

400

G

VCC(min) ≤ VCC ≤ VCC(max)

–

5

–

mV/G

TA = 25°C, CL = 1 nF, BW = 120 kHz

–

4.5

–

mVRMS

TA = 25°C, CL = 1 nF, BW = 240 kHz

–

6.5

–

mVRMS

TA = 25°C

–2

±1

2

%

TA = 25°C to 150°C

–2

±1

2

%

TA = –40°C to 25°C

–2

±1

2

%

TA = 25°C

–5

±3

5

mV

TA = 25°C to 150°C

–5

±3

5

mV

TA = –40°C to 25°C

–5

±3

5

mV

NOMINAL PERFORMANCE
Differential Magnetic Range

BDIFF

Sensitivity

Sens

ACCURACY PERFORMANCE
Noise
Sensitivity Error
Sensitivity Drift Over Temperature

VN
ESENS
ΔSensTC

Factory Quiescent Voltage Output Error

VOE

Quiescent Voltage Output
Temperature Error

VOUT(Q)TCQVO Ratiometry Error

VRatERRQVO

VCC = ±5% variation of nominal supply voltage

–7.5

±2.5

7.5

mV

Sens Ratiometry Error

RatERRSens

VCC = ±5% variation of nominal supply voltage

–1.25

±0.5

1.25

%

LIFETIME DRIFT CHARACTERISTICS [2]QVO Lifetime Drift

VQVOLife

TA = 25°C

–

1.4

–

mV

Sens Lifetime Drift

SensERRLife

TA = 25°C

–

0.6

–

%

QVO TC Lifetime Drift

VQVOTCLife

TA = 25°C to 150°C

–

1.5

–

mV

Sens TC Lifetime Drift

SensTCLife

TA = 25°C to 150°C

–

0.6

–

%

[1] All typical values are ±3 sigma.

[2] Typical lifetime value corresponds to worse case average drift found during AEC-Q100 qualification.

Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com

7

ACS37612

Coreless, High Precision, Hall-Effect Current Sensor IC

with Common-Mode Field Rejection and High Bandwidth (240 kHz)ACS37612LLUATR-010B3 PERFORMANCE CHARACTERISTICS: Valid over full range of TA and VCC = 3.3 V, unless otherwise specified
Characteristic

SymbolTest Conditions

Min.

Typ. [1]

Max.

Unit

–135

–

135

G

VCC(min) ≤ VCC ≤ VCC(max)

–

10

–

mV/G

TA = 25°C, CL = 1 nF, BW = 120 kHz

–

9

–

mVRMS

TA = 25°C, CL = 1 nF, BW = 240 kHz

–

12.5

–

mVRMS

TA = 25°C

–2

±1

2

%

TA = 25°C to 150°C

–2

±1

2

%

TA = –40°C to 25°C

–2

±1

2

%

TA = 25°C

–5

±3

5

mV

TA = 25°C to 150°C

–10

±3

10

mV

NOMINAL PERFORMANCE
Differential Magnetic Range

BDIFF

Sensitivity

Sens

ACCURACY PERFORMANCE
Noise

VN

Sensitivity Error

ESENS

Sensitivity Drift Over Temperature

ΔSensTC

Factory Quiescent Voltage Output Error

VOE

Quiescent Voltage Output
Temperature Error

VOUT(Q)TC

TA = –40°C to 25°C

–10

±3

10

mV

QVO Ratiometry Error

VRatERRQVO

VCC = ±3% variation of nominal supply voltage

–15

±5

15

mV

Sens Ratiometry Error

RatERRSens

VCC = ±3% variation of nominal supply voltage

–1.25

±0.5

1.25

%

LIFETIME DRIFT CHARACTERISTICS [2]QVO Lifetime Drift

VQVOLife

TA = 25°C

–

1.4

–

mV

Sens Lifetime Drift

SensERRLife

TA = 25°C

–

0.6

–

%

QVO TC Lifetime Drift

VQVOTCLife

TA = 25°C to 150°C

–

1.5

–

mV

Sens TC Lifetime Drift

SensTCLife

TA = 25°C to 150°C

–

0.6

–

%

[1] All typical values are ±3 sigma.

[2] Typical lifetime value corresponds to worse case average drift found during AEC-Q100 qualification.

Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com

8

ACS37612

Coreless, High Precision, Hall-Effect Current Sensor IC

with Common-Mode Field Rejection and High Bandwidth (240 kHz)ACS37612LLUATR-010B5 PERFORMANCE CHARACTERISTICS: Valid over full range of TA and VCC = 5 V, unless otherwise specified
Characteristic

SymbolTest Conditions

Min.

Typ. [1]

Max.

Unit

–200

–

200

G

VCC(min) ≤ VCC ≤ VCC(max)

–

10

–

mV/G

TA = 25°C, CL = 1 nF, BW = 120 kHz

–

9

–

mVRMS

TA = 25°C, CL = 1 nF, BW = 240 kHz

–

12.5

–

mVRMS

TA = 25°C

–2

±1

2

%

TA = 25°C to 150°C

–2

±1

2

%

TA = –40°C to 25°C

–2

±1

2

%

TA = 25°C

–5

±3

5

mV

TA = 25°C to 150°C

–10

±3

10

mV

NOMINAL PERFORMANCE
Differential Magnetic Range

BDIFF

Sensitivity

Sens

ACCURACY PERFORMANCE
Noise

VN

Sensitivity Error

ESENS

Sensitivity Drift Over Temperature

ΔSensTC

Factory Quiescent Voltage Output Error

VOE

Quiescent Voltage Output
Temperature Error

VOUT(Q)TC

TA = –40°C to 25°C

–10

±3

10

mV

QVO Ratiometry Error

VRatERRQVO

VCC = ±5% variation of nominal supply voltage

–7.5

±2.5

7.5

mV

Sens Ratiometry Error

RatERRSens

VCC = ±5% variation of nominal supply voltage

–1.25

±0.5

1.25

%

LIFETIME DRIFT CHARACTERISTICS [2]QVO Lifetime Drift

VQVOLife

TA = 25°C

–

1.4

–

mV

Sens Lifetime Drift

SensERRLife

TA = 25°C

–

0.6

–

%

QVO TC Lifetime Drift

VQVOTCLife

TA = 25°C to 150°C

–

1.5

–

mV

Sens TC Lifetime Drift

SensTCLife

TA = 25°C to 150°C

–

0.6

–

%

Min.

Typ.

Max.

Unit

[1] All typical values are ±3 sigma.

[2] Typical lifetime value corresponds to worse case average drift found during AEC-Q100 qualification.

ACS37612LLUATR-010B-C Variant
Characteristic

SymbolTest Conditions

CLAMP PERFORMANCE
Clamps Enabled–

EnabledAllegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com–

9

ACS37612

Coreless, High Precision, Hall-Effect Current Sensor IC

with Common-Mode Field Rejection and High Bandwidth (240 kHz)ACS37612LLUATR-015B5 PERFORMANCE CHARACTERISTICS: Valid over full range of TA and VCC = 5 V, unless otherwise specified
Characteristic

SymbolTest Conditions

Min.

Typ. [1]

Max.

Unit

–130

–

130

G

VCC(min) ≤ VCC ≤ VCC(max)

–

15

–

mV/G

TA = 25°C, CL = 1 nF, BW = 120 kHz

–

13

–

mVRMS

TA = 25°C, CL = 1 nF, BW = 240 kHz

–

19

–

mVRMS

TA = 25°C

–2

±1

2

%

TA = 25°C to 150°C

–2

±1

2

%

TA = –40°C to 25°C

–2

±1

2

%

TA = 25°C

–10

±6

10

mV

TA = 25°C to 150°C

–10

±6

10

mV

NOMINAL PERFORMANCE
Differential Magnetic Range

BDIFF

Sensitivity

Sens

ACCURACY PERFORMANCE
Noise

VN

Sensitivity Error

ESENS

Sensitivity Drift Over Temperature

ΔSensTC

Factory Quiescent Voltage Output Error

VOE

Quiescent Voltage Output
Temperature Error

VOUT(Q)TC

TA = –40°C to 25°C

–10

±6

10

mV

QVO Ratiometry Error

VRatERRQVO

VCC = ±5% variation of nominal supply voltage

–7.5

±2.5

7.5

mV

Sens Ratiometry Error

RatERRSens

VCC = ±5% variation of nominal supply voltage

–1.25

±0.5

1.25

%

LIFETIME DRIFT CHARACTERISTICS [2]QVO Lifetime Drift

VQVOLife

TA = 25°C

–

1.4

–

mV

Sens Lifetime Drift

SensERRLife

TA = 25°C

–

0.6

–

%

QVO TC Lifetime Drift

VQVOTCLife

TA = 25°C to 150°C

–

1.5

–

mV

Sens TC Lifetime Drift

SensTCLife

TA = 25°C to 150°C

–

0.6

–

%

[1] All typical values are ±3 sigma.

[2] Typical lifetime value corresponds to worse case average drift found during AEC-Q100 qualification.

Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com

10

ACS37612

Coreless, High Precision, Hall-Effect Current Sensor IC

with Common-Mode Field Rejection and High Bandwidth (240 kHz)ACS37612LLUATR-015U5 PERFORMANCE CHARACTERISTICS: Valid over full range of TA and VCC = 5 V, unless otherwise specified
Characteristic

SymbolTest Conditions

Min.

Typ. [1]

Max.

Unit

0

–

265

G

VCC(min) ≤ VCC ≤ VCC(max)

–

15

–

mV/G

TA = 25°C, CL = 1 nF, BW = 120 kHz

–

13

–

mVRMS

TA = 25°C, CL = 1 nF, BW = 240 kHz

–

19

–

mVRMS

TA = 25°C

–2

±1

2

%

TA = 25°C to 150°C

–2

±1

2

%

TA = –40°C to 25°C

–2

±1

2

%

TA = 25°C

–10

±6

10

mV

TA = 25°C to 150°C

–10

±6

10

mV

NOMINAL PERFORMANCE
Differential Magnetic Range

BDIFF

Sensitivity

Sens

ACCURACY PERFORMANCE
Noise

VN

Sensitivity Error

ESENS

Sensitivity Drift Over Temperature

ΔSensTC

Factory Quiescent Voltage Output Error

VOE

Quiescent Voltage Output
Temperature Error

VOUT(Q)TC

TA = –40°C to 25°C

–10

±6

10

mV

QVO Ratiometry Error

VRatERRQVO

VCC = ±5% variation of nominal supply voltage

–7.5

±2.5

7.5

mV

Sens Ratiometry Error

RatERRSens

VCC = ±5% variation of nominal supply voltage

–1.25

±0.5

1.25

%

LIFETIME DRIFT CHARACTERISTICS [2]QVO Lifetime Drift

VQVOLife

TA = 25°C

–

1.4

–

mV

Sens Lifetime Drift

SensERRLife

TA = 25°C

–

0.6

–

%

QVO TC Lifetime Drift

VQVOTCLife

TA = 25°C to 150°C

–

1.5

–

mV

Sens TC Lifetime Drift

SensTCLife

TA = 25°C to 150°C

–

0.6

–

%

[1] All typical values are ±3 sigma.

[2] Typical lifetime value corresponds to worse case average drift found during AEC-Q100 qualification.

Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com

11

ACS37612

Coreless, High Precision, Hall-Effect Current Sensor IC

with Common-Mode Field Rejection and High Bandwidth (240 kHz)FUNCTIONAL DESCRIPTION
Principle of Operation
When AC or DC current flows through a PCB copper trace or abusbar, as shown in Figure 7, the ACS37612 device will sense
the field difference between its two Hall elements H1 and H2,
represented by field components B- and B+. The device output
will be proportional to the differential field sensed, which is

proportional to the applied current. The relationship between
applied current and generated field is described as:
Bdiff = CF × I,
where Bdiff is the differential field (H1-H2), CF is the differential
coupling factor, and I is the current through the busbar/PCB trace.

Figure 7: Current Sensing Principle

Device Output Polarity
Current flowing through the PCB/busbar in the direction of pin
1 to pin 4, as shown in Figure 8, increases the output voltage
from its quiescent value toward the supply voltage rail (from
2.5 V to 4.5 V typical on bidirectional version, and 0.5 V to
4.5 V typical on unidirectional version).

The amount the output voltage increases is proportional to themagnitude of the applied current. Conversely, current flowing
in the opposite direction decreases the output voltage from its
quiescent value.

Figure 8: Sensor output polarity with respect tocurrent flow and sensor pins

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12

ACS37612

Coreless, High Precision, Hall-Effect Current Sensor IC

with Common-Mode Field Rejection and High Bandwidth (240 kHz)DYNAMIC RESPONSE CHARACTERISTICS

Figure 9: Response time, rise time, and propagation delay on 3.5 mm Reference PCB.
TA = 25°C, CBYPASS = 100 nF, CL = 1 nF, BW = 120 kHz

Figure 10: Response time, rise time, and propagation delay on Reference Busbar.
TA = 25°C, CBYPASS = 100 nF, CL = 1 nF, BW = 120 kHz

Allegro MicroSystems
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13Coreless, High Precision, Hall-Effect Current Sensor IC

ACS37612with Common-Mode Field Rejection and High Bandwidth (240 kHz)Power-On Reset (POR) and Undervoltage Lockout (UVLO) Operation –Nominal Supply Voltage = 5 V
The descriptions in this section assume: temperature = 25°C, no
output load (RL, CL ) , and no significant magnetic field is present.

near GND [6]. If VCC exceeds VUVLOE before the UVLO
Enable Counter reaches tUVLOE [5’] , the output will continue
to be VCC / 2.

• Power-Up. At power-up, as VCC ramps up, the output is ina high-impedance state. When VCC crosses VPORH (location[1] in Figure 11 and [1’] in Figure 12), the POR Releasecounter starts counting for tPORR. At this point, if VCC exceeds
VUVLOD [2’], the output will go to VCC / 2 after tUVLOD [3’].
If VCC does not exceed VUVLOD [2], the output will stay in thehigh-impedance state until VCC reaches VUVLOD [3] and thenwill go to VCC / 2 after tUVLOD [4].

• Coming out of UVLO. While UVLO is enabled [6] , if VCC
exceeds VUVLOD [7] , UVLO will be disabled after tUVLOD ,and the output will be VCC / 2 [8].
• Power-Down. As VCC ramps down below VUVLOE [6’, 9], theUVLO Enable Counter will start counting. If VCC is higher
than VPORL when the counter reaches tUVLOE , the UVLO
function will be enabled and the output will be pulled near
GND [10]. The output will enter a high-impedance state as
VCC goes below VPORL [11]. If VCC falls below VPORL before
the UVLO Enable Counter reaches tUVLOE , the output willtransition directly into a high-impedance state [7’].

• VCC drops below VCC(min) = 4.5 V. If VCC drops below
VUVLOE [4’, 5], the UVLO Enable Counter starts counting. If
VCC is still below VUVLOE when counter reaches tUVLOE , theUVLO function will be enabled and the output will be pulled
VCC

1

2

3

5.0

5

4

VUVLODVUVLOE
VPORH
VPORL

6

7

9

8

10 11

tUVLOEtUVLOE

GND

VOUT

Time

Slope =VCC / 2

2.5
tPORR

GND

tUVLODtUVLODHigh ImpedanceHigh Impedance

Time

Figure 11: POR and UVLO Operation – Slow Rise Time Case – 5 V Mode
VCC
5.0
VUVLODVUVLOE
VPORH
VPORL

1’

2’
3’

4’ 5’

6’ 7’

< tUVLOE

GND

VOUT

Time
tPORR
Slope =VCC / 2

2.5

< tUVLOE

Slope =VCC / 2tUVLOD
GND

High Impedance

Time

High Impedance

Figure 12: POR and UVLO Operation – Fast Rise Time Case – 5 V Mode

Allegro MicroSystems
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14Coreless, High Precision, Hall-Effect Current Sensor IC

ACS37612with Common-Mode Field Rejection and High Bandwidth (240 kHz)Power-On Reset (POR); Undervoltage Lockout (UVLO) Disabled –Nominal Supply Voltage = 3.3 V
Power-Up

VCC drops below VCC(min) = 3 V

At power-up, as VCC ramps up, the output is in a high-impedancestate. When VCC crosses VPORH (location [1] in Figure 13 and[1’] in Figure 14), the POR Release counter starts counting fortPORR [2], [2’] and the output will go to VCC / 2 after tPORD [3],[3’]. The temperature compensation engine will then adjust thedevice Sensitivity and QVO after time tTC [4], [4’].

If VCC drops below VPORH [5’] but remains higher than VPORL[6’], the output will continue to be VCC /2.

VCC

1

2

3

Power-Down
As VCC ramps down below VPORL [5],[7’], the output will enter ahigh-impedance state.

5

4

3.3
VPORH
VPORL
GND

VOUT

Time

tTC
tPORD

1.65

tPORR

GND

Slope =VCC / 2High ImpedanceHigh Impedance

Time

Figure 13: POR and UVLO Operation – Slow Rise Time Case – 3.3 V Mode
VCC

1’

3’
2’ 4’

5’ 6’

7’

3.3
VPORH
VPORL
GND

VOUT

Time

tTC
tPORD

1.65
GND

Slope =VCC / 2

Slope =VCC / 2High ImpedancetPORR

High Impedance

Time

Figure 14: POR and UVLO Operation – Fast Rise Time Case – 3.3 V Mode

Allegro MicroSystems
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15Coreless, High Precision, Hall-Effect Current Sensor IC

ACS37612with Common-Mode Field Rejection and High Bandwidth (240 kHz)DEFINITIONS OF ACCURACY CHARACTERISTICSSENSITIVITY (Sens)

RATIOMETRY

The amount of the output voltage increase is proportional to themagnitude of the magnetic field applied. This proportionality is
specified as the magnetic sensitivity, Sens (mv/G), of the device,
and it is defined as:

The device features a ratiometric output. This means that thequiescent voltage output, VOUT(Q), and the magnetic sensitivity,
Sens, are proportional to the supply voltage, VCC. The ratiometricchange in the quiescent voltage output is defined as:

Sens =

VOUT(B1) – VOUT(B2)
B1 – B2

where B1 and B2 are two different magnetic field levels.
SENSITIVITY DRIFT THROUGH TEMPERATURE
RANGE (ΔSENS TC)
Second-order sensitivity temperature coefficient effects cause themagnetic sensitivity, Sens, to drift from its expected value over
the operating ambient temperature range (TA). The Sensitivity
Drift Through Temperature Range (ΔSensTC) is defined as:
ΔSensTC =SensTA – SensEXPECTED(TA)
SensEXPECTED(TA)× 100 (%)

NONLINEARITY (E LIN)
The nonlinearity is a measure of how linear the output of thesensor IC is over the full current measurement range. The
nonlinearity is calculated as:{ [ELIN = 1–

SensBPRMax
SensBPRHalf[{

× 100 (%)

┌
┐
│
│
VCC
VRatERRQVO =– VOUTQ(VCC) × 1000 (mV)V×
│ OUTQ(5V)
│
5V
└
┘

(

)

and the ratiometric change (%) in sensitivity is defined as:┌││
RatERRSens = │1 –
│
│
└

(

┌
│
│
RatERRCLP = │1 –
│
│
└

(

Sens(VCC)
Sens(5V)

( )

)

VCC
5V

┐
│
│
│ × 100 (%)││┘

and the ratiometric change (%) in clamp voltage is defined as:
VCLP(VCC)
VCLP(5V)

( )
VCC
5V

)

┐
│
│
│ × 100 (%)││┘

where SensBPRMax is the sensitivity measured at the full range
output level and SensBPRHalf is the sensitivity measured at half ofthe full range output level.

Allegro MicroSystems
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16

ACS37612

Coreless, High Precision, Hall-Effect Current Sensor IC

with Common-Mode Field Rejection and High Bandwidth (240 kHz)QUIESCENT OUTPUT VOLTAGE (VOUT(Q))
The output of the sensor when no magnetic field is detected. Fora unipolar supply voltage, it nominally remains at 0.5 × VCC fora bidirectional device and 0.1 × VCC for a unidirectional device.
For example, in the case of a bidirectional output device, VCC =5 V translates into VOUT(Q) = 2.5 V. Variation in VOUT(Q) can be
attributed to the resolution of the Allegro linear IC quiescent voltage trim and thermal drift.
VOLTAGE OFFSET ERROR (VOE)The deviation of the device output from its ideal quiescent valueof 0.5 × VCC (bidirectional) or 0.1 × VCC (unidirectional) due tononmagnetic causes.
POWER-ON RESET VOLTAGE (V POR)
On power-up, to initialize to a known state and avoid current
spikes, the device is held in Reset state. The Reset signal isdisabled when VCC reaches VPORH and time tPORR has elapsed,allowing the output voltage to go from a high-impedance state
into normal operation. During power-down, the Reset signal isenabled when VCC reaches VPORL, causing the output voltage to
go into a high-impedance state. (Note that a detailed descriptionof POR can be found in the Functional Description section).
POWER-ON RESET RELEASE TIME (tPORR)
When VCC rises to VPORH, the Power-On Reset Counter starts.
The device output voltage will transition from a high-impedancestate to normal operation only when the Power-On Reset Counterhas reached tPORR and VCC has been maintained above VPORH.
OUTPUT SATURATION VOLTAGE (V SAT)
When output voltage clamps are disabled, the output voltage
can swing to a maximum of VSAT(HIGH) and to a minimum ofVSAT(LOW).

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17Coreless, High Precision, Hall-Effect Current Sensor IC

ACS37612with Common-Mode Field Rejection and High Bandwidth (240 kHz)DEFINITIONS OF DYNAMIC RESPONSE CHARACTERISTICS
POWER-ON TIME (tPO)When the supply is ramped to its operating voltage, the device
requires a finite time to power its internal components before
responding to an input magnetic field. Power-On Time, tPO, isdefined as the time it takes for the output voltage to settle within±10% of its steady-state value under an applied magnetic field,
after the power supply has reached its minimum specified operating voltage, VCC(min), as shown in Figure 15.
RISE TIME (tr)The time interval between a) when the sensor reaches 10% of its
full-scale value, and b) when it reaches 90% of its full-scale value,
as shown in Figure 16.
PROPAGATION DELAY (tPD)
The time interval between a) when the sensed current reaches
20% of its full-scale value, and b) when the sensor output reaches
20% of its full-scale value, as shown in Figure 16.
RESPONSE TIME (tRESPONSE)
The time interval between a) when the sensed current reaches
90% of its final value, and b) when the sensor output reaches 90%
of its full-scale value, as shown in Figure 17.

Figure 15: Power-On Time (tPO)(%)
90

Delay to Clamp (tCLP)
A large magnetic input step may cause the clamp to overshoot its
steady-state value. The Delay to Clamp, tCLP, is defined as: thetime it takes for the output voltage to settle within ±1% of Clamp
Voltage Dynamic Range, after initially passing through its steadystate voltage, as shown in Figure 18.

VCLP(HIGH)

Rise Time, tR
20
100
Propagation Delay, tPD

t

VOUT

tCLP
t1

VOUT

Figure 16: Propagation Delay (tPD) and Rise Time (tr)Current on Busbar/PCB

V

Current on Busbar/PCB

t2

(%)
90

t1= time at which output voltage initiallyreaches steady state clamp voltage
t2= time at which output voltage settles towithin 1% of steady state clamp voltage

Current on Busbar/PCB
VOUT
Response Time, tRESPONSE

Note: Times apply to both high clamp(shown) and low clamp.
0tFigure 18: Delay to Clamp

0t

Figure 17: Response Time (tRESPONSE)

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18

ACS37612

Coreless, High Precision, Hall-Effect Current Sensor IC

with Common-Mode Field Rejection and High Bandwidth (240 kHz)APPLICATION INFORMATION
Typical Application – Busbar Sensing

Figure 19: Busbar current sensing application – reference busbar design
The ACS37612 is ideal for busbar current sensing applications.

evaluation board designed to measure ±1000 A.

For a given current flowing through the busbar, the magnitude ofthe differential magnetic field sensed by the IC will depend on
the air gap between the busbar and the IC.

Note: Comparing the busbar described in Figure 19 to a bare busbar (without notch), the busbar with the 3 mm notch increased theoverall impedance by less than 1 µΩ, increasing busbar temperature by only few degrees during testing.

Adding a notch (width reduction) to the busbar at the location
where the sensor is placed significantly increases the magnitudeof the magnetic field, improving SNR. Keeping the notch length
short (2 to 3 mm) results in virtually no increase in the resistanceof the busbar or degradation of its thermal performance.
Different busbar and notch dimensions can be used to optimize
system performance and respond to application constraints.
Figure 19 and Table 1 highlight the dimensions of an Allegro

Skin Effect Consideration
Skin effect in the conductor tends to reduce the magnitude of thedifferential magnetic field measured by the IC at high frequencies(coupling factor) and therefore will influence the bandwidth of
the system and response time to transient current.
Skin effect will depend on busbar dimensions, sensor mounting
orientation, and distance between the busbar and the IC.

Table 1: Current range based on reference busbar design:
Busbar Application

Maximum Current (A)Coupling Factor at 2.5 mm Crystal Air Gap [1]Differential Field (G)IC Sensitivity (mV/G)

18 × 3 mm Busbar+ 3 mm Notch

±1000

0.19

±190

10

[1] Crystal air gap is defined as the distance from the busbar surface to the device sensing elements (considering active area depth).

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19

ACS37612

Coreless, High Precision, Hall-Effect Current Sensor IC

with Common-Mode Field Rejection and High Bandwidth (240 kHz)Multiple Busbar Design Options
The ACS37612 offers many different mounting possibilities,
addressing different needs (bandwidth, mounting tolerances, andcrosstalk). The figures below show different mounting options.

Figure 20: Rift Busbar Design

High mounting tolerances, medium coupling factor, high skin effect.
For DC to low frequency AC applications <1 kHz.

Figure 22: Dual Vertical Slit Busbar Design

High mounting tolerances, high coupling factor, low skin effect.
For DC to high frequency AC applications >100 kHz.

Refer to Allegro’s website (https://www.allegromicro.com) for
application notes explaining the tradeoffs between different
topologies.

Figure 21: Slit Busbar Design

High mounting tolerances, medium coupling factor, medium skin effect.
For DC to medium frequency AC applications <100 kHz.

Figure 23: Vertical Slit Busbar Design

High mounting tolerances, high coupling factor, low skin effect.
For DC to high frequency AC applications >100 kHz.

Allegro MicroSystems
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20

ACS37612

Coreless, High Precision, Hall-Effect Current Sensor IC

with Common-Mode Field Rejection and High Bandwidth (240 kHz)

Typical Application – PCB Sensing

Figure 24: PCB Current sensing application – 6-Layer reference PCB example
The ACS37612 can also be used in PCB applications where thecurrent flows directly in the PCB instead of on a busbar.
Multiple copper layers can be used to carry the current. Reducing the width of the copper traces under the sensor (neckdown)
increases the magnitude of the differential magnetic field measured by the IC.
Different copper layer dimensions and stackups can be used to
optimize performance and are specific to the constraints of theapplication. For example, in higher voltage applications, the top
layer would only be used for signal routing in order to use the
PCB replaced by dielectric layer for isolation.
Figure 24 and Table 2 highlight the dimensions of three Allegro
evaluation boards designed to measure a wide current range.
Care must be taken when routing the device signal to prevent

noise coupling to the supply or output lines.
The power plane in the neckdown area should also be avoided toprevent disturbing the magnetic field measured.
Skin Effect Consideration
Skin effect in the PCB current-carrying traces will tend to
reduce the differential magnetic field measured by the IC at highfrequencies (coupling factor) and therefore will influence thebandwidth of the system and response time to transient current.
Skin effect is generally limited on PCB application due to thincopper layer thickness, but the effect will depend on PCB copper
trace dimensions, number of layers, and layer thickness.
Skin effect will depend on PCB copper trace dimensions, numberof layers, and layer thickness.

Table 2: Current range based on reference PCB design:
PCB Application [1]Corresponding FullScale Current (A) [2]

Coupling Factor (G/A)

Differential Field (G)IC Sensitivity (mV/G)

5 Layers – Reference Design 3.5 mm – 015B5

±180

0.74

±133

15

5 Layers – Reference Design 3.5 mm – 010B5

±270

0.74

±200

10

5 Layers – Reference Design 4.5 mm – 015B5

±233

0.57

±133

15

5 Layers – Reference Design 4.5 mm – 010B5

±350

0.57

±200

10

5 Layers – Reference Design 7 mm – 015B5

±500

0.265

±133

15

5 Layers – Reference Design 7 mm – 010B5

±750

0.265

±200

10

[1] Maximum continuous current without proper cooling on these PCB designs should not exceed 200 A.
[2] Full-scale current is required to cover the full-scale output range (bidirectional = ±2 V).

Allegro MicroSystems
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21Coreless, High Precision, Hall-Effect Current Sensor IC

ACS37612with Common-Mode Field Rejection and High Bandwidth (240 kHz)PACKAGE OUTLINE DRAWINGFor Reference Only – Not for Tooling Use(Reference MO-153 AA)
NOT TO SCALE
Dimensions in millimeters
Dimensions exclusive of mold flash, gate burrs, and dambar protrusions
Exact case and lead configuration at supplier discretion within limits shown

3.00 ±0.10
D

0.45
8º
0º

8

6.40 BSC

E

E2

E

E1

0.65

8
0.20
0.09

1.70

1.87

4.40 ±0.10

6.10
3.15

A

E

E

+0.15
0.60
–0.10

1.27
1.00 REF

1

2
1.70

1

0.25 BSCE

SEATING PLANE
Branded Face

8×
0.10

B

1.10 MAXC

2

PCB Layout Reference View

GAUGE PLANECSEATING
PLANE
XXX

0.30
0.19

0.15
0.05

0.65 BSCA

Terminal #1 mark area

B

Reference land pattern layout (reference IPC7351 SOP65P640X110-8M); all pads a minimum of 0.20 mm from all adjacent pads;
adjust as necessary to meet application process requirements and PCB layout tolerances; when mounting on a multilayer PCB,
thermal vias can improve thermal dissipation (reference EIA/JEDEC Standard JESD51-5)

C

Branding scale and appearance at supplier discretion

D

Active Area Depth 0.36 mm REF

E

Hall elements (E1, E2); not to scale.

Date CodeC

Standard Branding Reference View
Line 1: Maximum 3 characters
Line 2: Maximum 5 characters

Line 1: Part NumberLine 2: Logo A, 4-digit Date Code

Figure 25: Package LU, 8-Pin TSSOP Package

Allegro MicroSystems
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22

ACS37612

Coreless, High Precision, Hall-Effect Current Sensor IC

with Common-Mode Field Rejection and High Bandwidth (240 kHz)

Revision History
NumberDate–

March 9, 2020

Initial release

Description

1

January 5, 2021

Updated Description (page 1), Selection Guide (page 2); added Power Derating plot (page 3); updated
Internal Bandwidth values, characteristic table headings, symbols, test conditions, and other editorialchanges (pages 5-10); removed Hall Spacing characteristic (page 5); updated Figure 6, Device Output
Polarity description and figure description (page 11); updated characteristic performance plot figure
descriptions (page 12); updated section title (page 13); Multiple Busbar Design Options figure descriptions(page 19); Typical Application - PCB Sensing description (page 20)

2

December 10, 2021

Added 010B5-C part variant (page 2, 9); removed lead-free symbol (page 2); updated Figure 4 (page 4);
updated Figure 6 (page 5); minor editoral updates

Copyright 2021, Allegro MicroSystems.
Allegro MicroSystems reserves the right to make, from time to time, such departures from the detail specifications as may be required to permit
improvements in the performance, reliability, or manufacturability of its products. Before placing an order, the user is cautioned to verify that the
information being relied upon is current.
Allegro’s products are not to be used in any devices or systems, including but not limited to life support devices or systems, in which a failure ofAllegro’s product can reasonably be expected to cause bodily harm.
The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems assumes no responsibility for its use; nor
for any infringement of patents or other rights of third parties which may result from its use.
Copies of this document are considered uncontrolled documents.
For the latest version of this document, visit our website:www.allegromicro.com

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23