CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

DC/DC CONVERTER
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24V DC-Input
Isolated 12Vdc Output
Efficiency up to 88.2%
Width only 32mm
20% Output Power Reserves (PowerBoost)
Full Power Between -25°C and +60°C
Soft-start Function Included
Minimal Inrush Current Surge
Reverse Input Polarity Protection
3 Year Warranty

PRODUCT DESCRIPTIONSHORT-FORM DATAThe Dimension CD-Series offer DIN rail DC/DC converters in the
92-120W output power range in a very compact housing. These
DC/DC converters are allowed to run with a battery or similarsources.

Output voltage
Adjustment range
Output current

The CD5.121 converts a 24V voltage to a 12V voltage.
The CD5.121 includes all the essential basic functions. The
devices also offer PowerBoost: Power reserves of 20%, which
may even be used continuously at temperatures up to +45°C.

PowerBoost

The output is electrically isolated from the input in a safe way.
The input is protected against reversed voltages and contains asoft start function.

Output ripple
Input voltage
Input voltage range

CD5.051

24V->5V

Related products

CD5.121

24V->12V

24V->24V

CD5.243

12V->24V

CD5.242

48V->24V

CD-Series

CD5.241

SLD2.100

CD5.241-L1

24V->5V
CD5.241-S1

24V->24V, NEC Class 2,
Spring-clamp-terminals,
24V->24V,
Spring-clamp-terminals,
Input-low, DC-OK signals

ORDER NUMBERS

Input current
Input inrush current
Efficiency
LossesTemperature range
Hold-up time
Dimensions
WeightDC 12V12 - 15V
8.0 - 6.4A
up to +60°C ambient
6.0 – 4.8A
at +70°C ambient
Derate linearly between +60°C and +70°C
9.6A
up to +45°C ambient
Linear decrease to nominal power
between +45°C and +60°C< 75mVpp
20Hz to 20MHz
DC 24V
18.0 to 32.4Vdc
full power
14.4 to 18.0Vdc with derating
typ. 4.6A
at 24Vdc input
typ. 1.2Apeak
88.2%
at 24Vdc input
12.8W
at 24Vdc input-25°C to +70°C
operational
typ. 7ms
at 24Vdc input
32x124x102mm WxHxD
425g

MAIN APPROVALS

DC/DC Converter

CD5.121

Standard unit

Accessory

ZM1.WALL
ZM10.WALL
ZM11.SIDE

Wall mounting bracket
Wall mounting bracket
Side mounting bracket

For details and the complete approval list, see chapter 18

UL 508

UL 60950-1

Class I Div 2

ATEXMarineMarineApr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

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CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

INDEX
Page

Page

1. Intended Use ................................................................ 3
2. Installation Instructions ................................................ 3
3. Input Voltage ................................................................ 5
4. Soft-start and Input Inrush Current Surge .................... 6
5. Output .......................................................................... 7
6. Hold-up Time ................................................................ 8
7. Efficiency and Power Losses ......................................... 9
8. Functional Diagram .................................................... 10
9. Front Side and User Elements .................................... 10
10. Terminals and Wiring ................................................. 11
11. Lifetime Expectancy ................................................... 12
12. MTBF .......................................................................... 12
13. EMC ............................................................................ 13
14. Environment ............................................................... 14
15. Protection Features .................................................... 15
16. Safety Features........................................................... 15
17. Dielectric Strength ...................................................... 16
18. Approved, Fulfilled or Tested Standards .................... 17
19. Regulatory Product Compliance ................................. 19

20. Physical Dimensions and Weight ............................... 20
21. Accessories................................................................. 2121.1. ZM1.WALL - Wall mounting bracket ................ 2121.2. ZM10.WALL - Wall/Panel Mount Bracket......... 2121.3. ZM11.SIDE - Side mounting bracket ................. 22
22. Application Notes....................................................... 23
22.1. Peak Current Capability .................................... 23
22.2. Back-feeding Loads .......................................... 23
22.3. Inductive and Capacitive Loads ........................ 23
22.4. Charging of Batteries ........................................ 24
22.5. External Input Protection ................................. 24
22.6. Requirements for the Supplying Source ........... 24
22.7. Parallel Use to Increase Output Power ............ 25
22.8. Parallel Use for Redundancy ............................ 25
22.9. Daisy Chaining of Outputs ................................ 26
22.10. Series Operation............................................... 26
22.11. Use in a Tightly Sealed Enclosure ..................... 26
22.12. Mounting Orientations ..................................... 27

The information presented in this document is believed to be accurate and reliable and may change without notice.
Some parts of this unit are patent by PULS (US patent No 091662,063, Des. 424,529, …).
No part of this document may be reproduced or utilized in any form without permission in writing from PULS GmbH.

TERMINOLOGY AND ABREVIATIONSPE andsymbolPE is the abbreviation for Protective Earth and has the same meaning as the symbol.

Earth, Ground

This document uses the term “earth” which is the same as the U.S. term “ground”.

t.b.d.

To be defined, value or description will follow later.

DC 24VA figure displayed with the AC or DC before the value represents a nominal voltage with standard tolerances
included.
E.g.: DC 12V describes a 12V battery disregarding whether it is full (13.7V) or flat (10V)24Vdc

A figure with the unit (Vac) at the end is a momentary figure without any additional tolerances included.

Apr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

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CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

1. INTENDED USEThis device is designed for installation in an enclosure and is intended for commercial use, such as in industrial control, process control,
monitoring and measurement equipment or the like. Do not use this device in equipment where malfunction may cause severe personal
injury or threaten human life.
If this device is used in a manner outside of its specification, the protection provided by the device may be impaired.

2. INSTALLATION INSTRUCTIONSWARNING

Risk of electrical shock, fire, personal injury or death.

- Turn power off before working on the device and protect against inadvertent re-powering.
- Do not open, modify or repair the device.
- Use caution to prevent any foreign objects from entering into the housing.
- Do not use in wet locations or in areas where moisture or condensation can be expected.
- Do not touch during power-on, and immediately after power-off. Hot surface may cause burns.
Obey the following installation instructions:This device may only be installed and put into operation by qualified personnel.
This device does not contain serviceable parts. The tripping of an internal fuse is caused by an internal defect.
If damage or malfunction should occur during installation or operation, immediately turn power off and send unit to the factory for
inspection.
Install device in an enclosure providing protection against electrical, mechanical and fire hazards.
Install the device onto a DIN rail according to EN 60715 with the input terminals on the bottom of the device. Other mounting
orientations require a reduction in output current. Make sure that the wiring is correct by following all local and national codes. Useappropriate copper cables that are designed for a minimum operating temperature of 60°C for ambient temperatures up to +45°C, 75°C
for ambient temperatures up to +60°C and 90°C for ambient temperatures up to +70°C.
Ensure that all strands of a stranded wire enter the terminal connection. Unused screw terminals should be securely tightened.
The device is designed for pollution degree 2 areas in controlled environments. No condensation or frost is allowed.
The enclosure of the device provides a degree of protection of IP20. The enclosure does not provide protection against spilled liquids.
The isolation of the device is designed to withstand impulse voltages of 1.5kV according to IEC 60664-1.
The input can be powered from batteries or similar DC sources. The voltage between the input terminals and ground must not exceed
60Vdc continuously. The ripple voltage in the low frequency range between 50Hz and 10kHz must be negligible when used in marine
applications.
The input must be powered from a PELV or SELV source or an "Isolated Secondary Circuit" in order to maintain a SELV or PELV output.
Check for correct input polarity. The device will not operate when the voltage is reversed.
A disconnecting means shall be provided for the input of the device.
The device is designed as “Class of Protection III” equipment according to IEC 61140. A PE (ground) connection is not required. However,connecting the chassis ground terminal to ground can be beneficial to gain a high EMI immunity.
The device is designed for convection cooling and does not require an external fan. Do not obstruct airflow and do not cover ventilation
grid! The device is designed for altitudes up to 5000m. Above 2000m a reduction in output current is required.
Keep the following minimum installation clearances: 40mm on top, 20mm on the bottom, 5mm left and right side. Increase the 5mm to15mm in case the adjacent device is a heat source. When the device is permanently loaded with less than 50%, the 5mm can be reduced
to zero.
The device is designed, tested and approved for branch circuits up to 50A without additional protection device. If an external fuse isutilized, do not use circuit breakers smaller than 10A B- or 8A C-Characteristic to avoid a nuisance tripping of the circuit breaker.
Apr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

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CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

The maximum surrounding air temperature is +70°C. The operational temperature is the same as the ambient or surrounding air
temperature and is defined 2cm below the device.
The device is designed to operate in areas between 5% and 95% relative humidity.
Installation Instructions for Hazardous Location Areas
The device is suitable for use in Class I Division 2 Groups A, B, C, D locations and for use in Group II Category 3 (Zone 2) environments.
Classification: ATEX: EPS 08 ATEX 1 142 X, II 3G Ex ec nC IIC T4 Gc / IECEx EPS 14.0001X

WARNING EXPLOSION HAZARDS!
Substitution of components may impair suitability for this environment.
Do not disconnect the device or operate the voltage adjustment unless power has been switched off or the area is known to be nonhazardous.
A suitable enclosure must be provided for the end product which has a minimum protection of IP54 and fulfils the requirements of the
EN 60079-0.
Reduced output current conditions must be considered for high ambient temperatures and non-standard mounting orientations.

Apr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

4/27

CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

3. INPUT VOLTAGE
Input voltage
Input voltage rangenom.

DC 24V
18.0-32.4Vdc
14.4-18.0Vdc
36.0Vdc

max.
Allowed voltage between input and
earth

max.

60Vdc or42.2Vac
5Vpp

Turn-on voltage
Shut-down voltage

typ.
typ.
typ.

17.5Vdc
14.0Vdc
35.0Vdc

Input current
Start-up delay
Rise time

typ.
typ.
typ.
typ.
max.
typ.

4.6A
420ms
210ms
240ms
500mV
3 000µF

Allowed input ripple voltage

Turn-on overshootInput capacitancemax.

47Hz-500Hz, the momentary input voltage must always be within
the specified limits
steady-state value, see Fig. 3-1
steady-state value, see Fig. 3-1
steady-state value, see Fig. 3-1
at 24Vdc input and output 12V, 8A, see Fig. 3-4
see Fig. 3-3
0mF, 12V, constant current load 5A, see Fig. 3-3
8mF, 12V, constant current load 5A, see Fig. 3-3
see Fig. 3-3
external capacitors on the input voltage bus are allowed without
any limitations

Fig. 3-2 Allowable output current below 18V input
voltageFig. 3-1 Input voltage range

Rated input range

POUT

full power, see Fig. 3-2 for derating below 18.0Vdc
max. 60s or with derating see Fig. 3-2
absolute maximum continuous input voltage with no damage to
the DC/DC converterin case the output voltage is not grounded

Output Current

8Turn-onShut -dow n

10A

6

32.4Vdc
35.0Vdc

17.5Vdc
18.0Vdc

14.0Vdc

VIN(a) Ambient < 45°C(b) Ambient < 60°C(c) Ambient < 70°C

420Input Voltage
14.4

14

Fig. 3-3 Turn-on behavior, definitions

16

18

20

Input
Current,
typ.

8A

dc
8V
1
:
ut
c
In p
Vd
: 24
t
u
In p

6

Start-up
delay

Rise
Time

Overshoot4

OutputVoltage

24Vdc

Fig. 3-4 Input current vs. output load

Input
Voltage

- 5%

22

2
Output Current

0
1

2

3

4

5

6

7

8

Apr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

9 10A

5/27

CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

4. SOFT-START AND INPUT INRUSH CURRENT SURGE
Inrush current limitation
An active inrush limitation circuit (inrush limiting resistor which is bypassed by a relay contact) limits the input inrush current after turnon of the input voltage.
The charging current into EMI suppression capacitors is disregarded in the first microseconds after switch-on.
Inrush current

max.
typ.
typ.

Inrush energy

1.6Apeak
1.2Apeaknegligible-25°C to +70°C, input: 24Vdc-25°C to +70°C, input: 24Vdc-25°C to +70°C, input: 24Vdc

Fig. 4-1 Input inrush current, typical behavior

Input Current
Input Voltage

Input:
Output:Ambient:

24Vdc
12V, 8A, constant current load
25°C

Upper curve:
Middle curve:
Lower curve:Time basis:

Input current 2A / DIVInput voltage 20V / DIV
Output voltage 10V / DIV
100ms / DIV

Output Voltage

Soft-start function:
After the DC/DC converter is turned on, the internal output current rises slowly to its nominal value. This method charges the output
capacitors (internal and external capacitors) slowly and avoids high input currents during turn-on. High input currents can produce ahigh voltage drop on the input wiring (especially with long and thin cables) which reduces the terminal voltage on the DC/DC converter.
If the terminal voltage is below the shut-down voltage, the DC/DC converter will turn-off and will make a new start-up attempt. Thiseffect is avoided with the integrated soft-start function. Please note, that this function increases the rise time of the output voltage by asmall amount.
Fig. 4-2 Soft-start behavior

Input Current

Input:
24Vdc
Output:
12V, 8A, constant current load
Ambient:
25°C
No additional external output capacitors
Upper curve:
Lower curve:Time basis:

Input current 2A / DIV
Output voltage 5V / DIV
20ms / DIV

Output Voltage

Apr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

6/27

CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

5. OUTPUT
Output voltage
Adjustment range

nom.

12V
12-15Vguaranteed
max.
16.1V
at clockwise end position of potentiometer
12.0V±0.2%, at full load, cold unit
max.
25mV
Input voltage variations between 18 to 32.4Vdc
max.
120mV
static value, 0A → 8A
max.
75mVpp20Hz to 20MHz, 50Ohm
nom.
8.0A
at 12V and up to +60°C ambient temperature
nom.
6.0A
at 12V and +70°C ambient temperature
nom.
6.4A
at 15V and up to +60°C ambient temperature
nom.
4.8A
at 15V and +70°C ambient temperature
Input voltage range 18.0-32.4Vdc: Derate linearly between +60°C and +70°C, see chapter 3
Input voltage range 14.4-18.0Vdc: Derate linearly between +45°C and +70°C, see chapter 3
nom.
9.6A
at 12V and up to +45°C ambient temperature
nom.
7.7A
at 15V and up to +45°C ambient temperaturePowerBoost decreases linearly to nominal power between +45°C and +60°C, see chapter 14

Factory settingLine regulation
Load regulation
Ripple and noise voltage
Output current

PowerBoost *)Short-circuit current

min.
max.
typ.

Output capacitance*) PowerBoost

14A
18A
6 500µF

continuous current, short circuit impedance 150mOhm
continuous current, short circuit impedance 150mOhm

This power/ current is continuously allowed up to an ambient temperature of +45°C.
Above +45°C, do not use this power/ current longer than a duty cycle of 10% and/ or not longer than 1 minute every 10 minutes.

Fig. 5-1 Output voltage vs. output current at 24Vdc input
voltage, typ.

Fig. 5-2 Current limitation vs. input voltage,(11.5V constant voltage load), typ.

Output Current

Output Voltage

11A

18V
Adjustment
Range

15

10.8

12

10.6

9

10.4

6

10.2
10.0

3
Output Current

0
0

2

4

6

Input Voltage

9.8

8 10 12 14 16 18A

15

18

21

24

27

30 33Vdc

Peak current capability (up to several milliseconds)
The DC/DC converter can deliver a peak current, which is higher than the specified short term current. This helps to start current
demanding loads or to safely operate subsequent circuit breakers.
The extra current is supplied by the output capacitors inside the DC/DC converter. During this event, the capacitors will be discharged
and causes a voltage dip on the output. Detailed curves can be found in chapter 22.1.
Peak current voltage dips

typ.
typ.
typ.

from 12V to 8.3V
from 12V to 6.2V
from 12V to 4.3V

at 16A for 50ms, resistive load
at 40A for 2ms, resistive load
at 40A for 5ms, resistive load

Apr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

7/27

CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

6. HOLD-UP TIME
The input side of the DC/DC converter is equipped with a bulk capacitor which keeps the output voltage alive for a certain period of time
when the input voltage dips or is removed. The bulk capacitor can be discharged by loading the DC/DC converter on the output side or
through a load which is parallel to the input. There is no protection in the DC/DC converter which prevents current from flowing back to
the input terminals. If prevention is needed, an external diode should be used.
Hold-up Time

typ.
typ.

12.8ms
7ms

input 24Vdc, output: 12Vdc, 4A, see Fig. 6-1
input 24Vdc, output: 12Vdc, 8A, see Fig. 6-1

Fig. 6-1 Hold-up time vs. input voltage
Hold-up Time

12ms
10

(a)

(b)

8

(c)

(d)

6
4
Input Voltage(a) 12V, 4A, typ.
(b) 12V, 4A, min.
(c) 12V, 8A, typ.
(d) 12V, 8A, min.

20

24

2
0
18

22

26

28Vdc

Fig. 6-2 Shut-down test setup

S1

+
DC
Source-DC/DC
Converter
Input+

Fig. 6-3 Shut-down behavior, definitions

IntputVoltage

S1 opens

+

CD5

Load

Output --- 5%

OutputVoltage
Hold-up Time

Note: At no load, the hold-up time can be up to several seconds. The green DC-OK LED is also on during this time.

Apr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

8/27

CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

7. EFFICIENCY AND POWER LOSSES
Efficiency
Power losses

Fig. 7-1

Input 24Vdc
88.2%
0.6W
6.4W
12.8W
16.8W

typ.
typ.
typ.
typ.
typ.

Efficiency vs. output current at 12V output and
24Vdc input voltage, typ.

Efficiency

at 12V, 8A
at no output load
at 12V, 4A
at 12V, 8A
at 12V, 9.6A (PowerBoost)Fig. 7-2

Losses vs. output current at 12V output and
24Vdc input voltage, typ.

Power Losses

90%

18W

89

15

88

12

87

9

86

6

85

3
Output Current

84
1Fig. 7-3

2

3

4

5

Output Current

0
6

7

0

8A

Efficiency vs. input voltage at 12V, 8A, typ.

Fig. 7-4

1

3

4

5

6

7

8A

Losses vs. input voltage at 12V, 8A, typ.

Efficiency

Power Losses

89%

24W

88.5

20

88.0

16

87.5

12

87.0

8
4

86.5
86.0
18

2

Input Voltage

20

22

24

26

Input Voltage

028

30 32Vdc

18

20

22

24

26

28

Apr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

30 32Vdc

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CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

8. FUNCTIONAL DIAGRAM
Fig. 8-1 Functional diagram

OutputVoltage
Regulator+
ChassisGroundInput Fuse&
Input Filter

ReversePolarity
Protection&
InrushLimiter

OverTemperature
Protection

Power
Converter

OutputFilterOutputOverVoltage
Protection

VOUT

+
+
DC
ok

9. FRONT SIDE AND USER ELEMENTS
Fig. 9-1 Front sideA

Input terminals
Screw terminals+ Positive input- Negative (return) input
Chassis ground: can be used to bond the housing to PE
Ground this terminal to minimize high-frequency emissions.

B

Output terminals
Screw terminals, dual terminals per pole, both pins are equal+ Positive output- Negative (return) output
Screw terminals

C

Output voltage potentiometer
Open the flap to set the output voltage. Factory set: 12.0V

D

DC-OK LED (green)
On when the voltage on the output terminals is > 8.5V

Apr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

10/27

CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

10. TERMINALS AND WIRINGType
Solid wire
Stranded wire
American Wire Gauge
Wire stripping length
Screwdriver
Recommended tightening torqueInput
screw terminals
max. 6mm2
max. 4mm2
20-10 AWG
7mm
3.5mm slotted or Pozidrive
No 2
1Nm

Outputscrew terminals
max. 6mm2
max. 4mm2
20-10 AWG
7mm
3.5mm slotted or Pozidrive
No 2
1Nm

Instructions:a) The external circuitry of all terminals must meet the safety requirements stipulated by IEC/EN/UL 60950-1: SELV.
b) Use appropriate copper cables that are designed for an operating temperature of:
60°C for ambient up to 45°C and
75°C for ambient up to 60°C minimum.
c) Follow national installation codes and installation regulations!
d) Ensure that all strands of a stranded wire enter the terminal connection!
e) Do not load the terminals with more than 25A! See chapter 22.9f) Screws of unused terminal compartments should be securely tightened.
g) Ferrules are allowed.
h) Do not connect or disconnect the wires from the terminals below -25°C.

Apr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

11/27

CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

11. LIFETIME EXPECTANCYThe Lifetime expectancy shown in the table indicates the minimum operating hours (service life) and is determined by the lifetime
expectancy of the built-in electrolytic capacitors. Lifetime expectancy is specified in operational hours and is calculated according to thecapacitor’s manufacturer specification. The prediction model allows only a calculation of up to 15 years from date of shipment.

Lifetime expectancy

Input 24Vdc
173 000h
63 000h35 000h
179 000h

at 12V, 4A and 40°C
at 12V, 8A and 40°C
at 12V, 9.6A and 40°C
at 12V, 8A and 25°C

12. MTBF
MTBF stands for Mean Time Between Failure, which is calculated according to statistical device failures, and indicates reliability of adevice. It is the statistical representation of the likelihood of a unit to fail and does not necessarily represent the life of a product.
The MTBF figure is a statistical representation of the likelihood of a device to fail. A MTBF figure of e.g. 1 000 000h means thatstatistically one unit will fail every 100 hours if 10 000 units are installed in the field. However, it can not be determined if the failed unit
has been running for 50 000h or only for 100h.

MTBF SN 29500, IEC 61709
MTBF MIL HDBK 217F

Input 24Vdc
1 161 000h
1 904 000h
610 000h
817 000h

at 12V, 8A and 40°C
at 12V, 8A and 25°C
at 12V, 8A and 40°C; Ground Benign GB40
at 12V, 8A and 25°C; Ground Benign GB25

Apr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

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CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

13. EMCThe DC/DC converter is suitable for applications in industrial environment as well as in residential, commercial and light industry
environment without any restrictions.
EMC Immunity
Electrostatic discharge
Electromagnetic RF field
Fast transients (Burst)
Surge voltage on input
Surge voltage on output
Conducted disturbance

Generic standards: EN 61000-6-1 and EN 61000-6-2
EN 61000-4-2
Contact discharge
Air discharge
EN 61000-4-3
80MHz-2.7GHz
EN 61000-4-4
Input lines
Output lines
EN 61000-4-5+→+/- → chassis groundEN 61000-4-5+→+ / - → chassis groundEN 61000-4-6
0.15-80MHz

8kV
15kV
10V/m
4kV
2kV
1kV
2kV
500V
1kV
10V

Criterion A
Criterion A
Criterion A
Criterion A
Criterion A
Criterion A
Criterion A
Criterion A
Criterion A
Criterion A

Criterions:
A: DC/DC converter shows normal operation behavior within the defined limits.
C: Temporary loss of function is possible. DC/DC converter may shut-down and restarts by itself. No damage or hazards for the DC/DC converter will occur.

EMC Emission
Conducted emission on input

Generic standards: EN 61000-6-3 and EN 61000-6-4
IEC/CISPR 16-1-2, IEC/CISPR 16-2-1

Limits for DC power ports
acc. EN 61000-6-3 fulfilled
Class B

Radiated emission
EN 55011, EN 55032
This device complies with FCC Part 15 rules.
Operation is subjected to following two conditions: (1) this device may not cause harmful interference, and (2) this device must accept
any interference received, including interference that may cause undesired operation.

Switching frequency
Variable between 90kHz and 145kHz depending on load and input voltage(output current > 0.5A)

Apr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

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CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

14. ENVIRONMENT
Operational temperature *)Storage temperature
Output derating-25°C to +70°C
reduce output power according Fig. 14-1
-40 to +85°C
for storage and transportation
2.5W/K
between +60°C and +70°C
Additional derating is required for input voltages below 18.0Vdc, see chapter 3
5 to 95% r.H.
IEC 60068-2-30
2-17.8Hz: ±1.6mm; 17.8-500Hz: 2g
IEC 60068-2-6
2 hours / axis
30g 6ms, 20g 11ms
IEC 60068-2-27
3 bumps / direction, 18 bumps in total
0 to 6000m
reduce output power or ambient temperature above
2000m sea level.
6W/1000m or 5K/1000m
for altitudes >2000m, see Fig. 14-2
III
IEC 62477-1, EN 50178, altitudes up to 2000m
II
altitudes from 2000m to 6000m
2
IEC 62477-1, EN 50178, not conductive

Humidity **)Vibration sinusoidal ***)
Shock ***)
Altitude
Altitude derating
Over-voltage category
Degree of pollution*) Operational temperature is the same as the ambient temperature and is defined as the air temperature 2cm below the unit.
**) Do not energize while condensation is present***) Tested in combination with DIN rails according to EN 60715 with a height of 15mm and a thickness of 1.3mm and standard mounting orientation.

Fig. 14-1 Output current vs. ambient temp.
(Inom 8A; Iout with PowerBoost = 9.6A)

Allowable Output
Current at 12V

short term

Fig. 14-2 Output current vs. altitude at 24V

Allowable Output
Current at 12V

10A

10A

8

8

6

6

4

4

2

2

0
-25

Ambient Temperature

0

20

45

short term
C
B
A

A... Tamb < 60°C
B... Tamb < 50°C
C... Tamb < 40°C

Altitude0

60 70°C

0

2000

4000

Apr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

6000m

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CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

15. PROTECTION FEATURES
Output protection
Output over-voltage protection

Reverse input polarity protection
Output over-current protection
Degree of protection
Penetration protection
Over-temperature protection
Input transient protection
Internal input fuse*)

Electronically protected against overload, no-load and short-circuits *)typ. 16.5Vdc
in case of an internal power supply defect, a redundant circuit
limits the maximum output voltage. The output shuts down andmax. 16.8Vdc
automatically attempts to restart.
Includedunit does not start when input voltage is reversed
electronically limited *)see Fig. 5-1
IP 20
EN/IEC 60529> 3.5mme.g. screws, small partsyes
output shut-down with automatic restart
MOV
Metal Oxide Varistor
included
not user replaceable

In case of a protection event, audible noise may occur.

16. SAFETY FEATURESClassification of output voltage
Class of protection

Isolation resistancePE resistance
Touch current (leakage current)

*)

SELV
PELV
III

IEC/EN 60950-1
IEC/EN 60204-1, EN 50178, IEC 62477-1, IEC 60364-4-41
PE (Protective Earth) connection not required. A connection of
the “Chassis Ground” pin to earth is recommended for best EMI
performance> 5MOhm
input to output, 500Vdc< 0.1Ohm
between housing and Chassis Ground terminal
The leakage current which is produced by the DC/DC converter itself depends on the input
voltage ripple and need to be investigated in the final application.
For a smooth DC input voltage, the produced leakage current is less than 100µA.

provided, that the input voltage meets the requirements of chapter 2.

Apr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

15/27

CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

17. DIELECTRIC STRENGTH
The output voltage is floating and has no ohmic connection to the ground.
Type and factory tests are conducted by the manufacturer. Field tests may be conducted in the field using the appropriate test
equipment which applies the voltage with a slow ramp (2s up and 2s down). Connect all input terminals together as well as all output
poles before conducting the test. When testing, set the cut-off current settings to the value in the table below.
Type test

60s

A
1500Vac

B
1500Vac

C
500VacFactory test

5s

1500Vac

1500Vac

500VacField test

5s

1000Vac

1000Vac

500VacCut-off current setting> 30mA> 30mA> 12mA

Fig. 17-1 Dielectric strength

Input
+

B

-

OutputA
Chassisground+C-

To fulfill the PELV requirements according to EN60204-1 § 6.4.1, werecommend that either the + pole, the – pole or any other part of the output
circuit shall be connected to the protective earth system. This helps to avoid
situations in which a load starts unexpectedly or can not be switched off
when unnoticed earth faults occur.

Apr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

16/27

CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

18. APPROVED, FULFILLED OR TESTED STANDARDSUL 508

IEC 60950-1

UL 60950-1

Class I Div 2Class I Div 2

ATEX

IECEx

Marine (DNV)

UL Certificate
Listed equipment for category NMTR - Industrial Control Equipment
Applicable for US and Canada
E-File: E198865
CB Scheme Certificate
General safety requirements for Information Technology Equipment (ITE)UL Certificate
Recognized component for category QQGQ - Information Technology
Equipment (ITE)
Applicable for US and Canada
E-File: E137006
CSA Certificate
Power Supplies for Hazardous Location
Applicable for Canada and US
CSA Class: 5318-01 (Canada), 5318-81 (USA)
Temperature Code: T4
Groups: A, B, C and D
UL Certificate
Listed equipment for category NRAD - Listed equipment Industrial
Control Equipment for Use in Hazardous Locations
Applicable for US and Canada
E-File: E327416
Temperature Code: T4A
Groups: A, B, C and D
Agency Certificate (Bureau Veritas)
EN 60079-0 Explosive atmospheres - General requirements
EN 60079-7, EN 60079-15 Equipment protection by type of protection"e" and "n"Certificate: EPS 08 ATEX 1 142 X
Temperature Code: T4
Type of Protection: ec nC
IECEx Certificate
IEC 60079-0 Explosive atmospheres - General requirements
IEC 60079-15 Equipment protection by type of protection "n"Certificate: IECEx EPS 14.0001X
Temperature Code: T4
Type of Protection: ec nC
DNV Certificate
DNV Type approved product
Certificate: TAA00001ST
Temperature: Class D
Humidity: Class B
Vibration: Class C
EMC: Class A
Enclosure: Class A

Apr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

17/27

CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

Marine (ABS)IEC 60068-2-60

ISA-71.04 G3

VDMA 24364

ABS Design Assessment Certificate
ABS (American Bureau of Shipment) assessed product
Certificate: 17-HG1599236-PD
Manufacturer's Declaration (Online Document)
Environmental Tests, Flowing Mixed Gas Corrosion Test
Test Ke - Method 4
H2S: 10ppb
NO2: 200ppb
Cl2: 10ppb
SO2: 200ppb
Test Duration: 3 weeks, which simulates a service life of at least 10 years.
Manufacturer's Declaration (Online Document)
Airborne Contaminants Corrosion Test
Severity Level: G3 Harsh
H2S: 100ppb
NOx: 1250ppb
Cl2: 20ppb
SO2: 300ppb
Test Duration: 3 weeks, which simulates a service life of at least 10 years
Paint Wetting Impairment Substances Test (or LABS-Test)
Tested for Zone 2 and test class C1 according to VDMA 24364-C1-L/W for
solvents and water-based paints

Apr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

18/27

CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

19. REGULATORY PRODUCT COMPLIANCE
EU Declaration of Conformity

REACH Regulation (EU)

WEEE Regulation

KC

UKCA

CCC

The CE mark indicates conformance with the- EMC directive- ATEX directive- RoHS directive
Manufacturer's Declaration
EU regulation regarding the Registration, Evaluation, Authorisation andRestriction of Chemicals (REACH) fulfilled.
EU Regulation (EC) 1907/2006.
Manufacturer's Declaration
EU Regulation on Waste Electrical and Electronic Equipment
Registered as business to business (B2B) products.
EU Regulation 2012/19/EU
KC Korean Certification
Korean - Registration of Broadcasting and Communication Equipment
Registered under Clause3, Article 58-2 of Radio Waves Act.
Registration No. R-R-PUG-CD5_121
UKCA Declaration of Conformity
Trade conformity assessment for England, Scotland and WalesThe UKCA mark indicates conformity with the UK Statutory
Instruments
2016 No.1091,
2016 No.1107,
2012 No.3032
CCC Certificate
Certificate for devices made in Suzhou/China (PULS Electronics):
2021122303114823
Certificate for devices made in Chomutov/Czech Republic (PULS
investiční): 2021122303114798
CCC-ExApr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

19/27

CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

20. PHYSICAL DIMENSIONS AND WEIGHT
WeightDIN rail

Installation Clearances

425g
Use 35mm DIN rails according to EN 60715 or EN 50022 with a height of 7.5 or 15mm.
The DIN rail depth must be added to the unit depth (102mm) to calculate the total required installation
depth.
See chapter 2

Fig. 20-1 Front viewFig. 20-2 Side viewApr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

20/27

CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

21. ACCESSORIES
21.1. ZM1.WALL - WALL MOUNTING BRACKETThis bracket is used to mount specific Dimension units onto a flat surface without utilizing a DIN rail. The two aluminum brackets andthe black plastic slider of the unit have to be removed, so that the two steel brackets can be mounted.
Fig. 21-1 ZM1.WALL - Wall mounting bracket*)

Fig. 21-2 ZM1.WALL attached to PSU*)

PSU for illustration purpose only.

21.2. ZM10.WALL - WALL/PANEL MOUNT BRACKETThis bracket is used to mount the devices on a wall/panel without utilizing the DIN rail. The bracket can be mounted without detaching
the DIN rail brackets from the power supply.
Fig. 21-3 ZM10.WALL - Wall mounting bracket*)

Fig. 21-4 ZM10.WALL attached to PSU *)PSU for illustration purpose only.

Apr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

21/27

CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

21.3. ZM11.SIDE - SIDE MOUNTING BRACKETThis bracket is used to mount Dimension units sideways with or without utilizing a DIN rail. The two aluminum brackets and the black
plastic slider of the unit have to be detached, so that the steel brackets can be mounted.
For sideway DIN rail mounting, the removed aluminum brackets and the black plastic slider need to be mounted on the steel bracket.
Fig. 21-5 ZM11.SIDE - Side mounting bracket*)*)Fig. 21-6 Side mounting with DIN rail brackets*)

PSU for illustration purpose only.

Apr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

22/27

CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

22. APPLICATION NOTES
22.1. PEAK CURRENT CAPABILITY
Solenoids, contactors and pneumatic modules often have a steady state coil and a pick-up coil. The inrush current demand of the pickup coil is several times higher than the steady-state current and usually exceeds the nominal output current (including the PowerBoost)
The same situation applies, when starting a capacitive load.
Branch circuits are often protected with circuit breakers or fuses. In case of a short or an overload in the branch circuit, the fuse needs acertain amount of over-current to trip or to blow. The peak current capability ensures the safe operation of subsequent circuit breakers.
Assuming the input voltage is turned on before such an event, the built-in large sized output capacitors inside the DC/DC converter candeliver extra current. Discharging this capacitor causes a voltage dip on the output. The following two examples show typical voltage
dips:Fig. 22-1 Peak loading with 2x the nominal current for
50ms, typ.

Fig. 22-2 Peak loading with 5x the nominal current for
5ms, typ.

12V

12V

OutputVoltage

OutputVoltage

8.3V

4.3V
40A
16A

OutputCurrent

OutputCurrent

1A

1A
10ms/DIV

1ms/DIV

Peak load 16A (resistive load) for 50ms
Output voltage dips from 12V to 8.3V.

Peak load 40A (resistive load) for 5ms
Output voltage dips from 12V to 4.3V.

22.2. BACK-FEEDING LOADS
Loads such as decelerating motors and inductors can feed voltage back to the DC/DC converter. This feature is also called return voltage
immunity or resistance against Back- E.M.F. (Electro Magnetic Force).
This DC/DC converter is resistant and does not show malfunctioning when a load feeds back voltage to the DC/DC converter. It does notmatter, whether the DC/DC converter is on or off.
The maximum allowed feed-back-voltage is 16Vdc. The absorbing energy can be calculated according to the built-in large sized output
capacitance which is specified in chapter 5.

22.3. INDUCTIVE AND CAPACITIVE LOADSThe unit is designed to supply any kind of loads, including unlimited capacitive and inductive loads.

Apr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

23/27

CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

22.4. CHARGING OF BATTERIESThe DC/DC converter can be used to charge lead-acid or maintenance free 12V VRLA batteries.
Instructions for charging batteries:a)Ensure that the ambient temperature of the DC/DC converter is below 45°Cb)

Do not use DC/DC converters in mounting orientations other than the standard mounting orientation (input terminals on thebottom and output terminals on top of the unit).

c)

Set output voltage (measured at no load and at the battery end of the cable) very precisely to the end-of-charge voltage.
End-of-charge voltage

13.9V

13.75V

13.6V

13.4V

Battery temperature

10°C

20°C

30°C

40°C

d)

Use a 10A circuit breaker (or blocking diode) between the DC/DC converter and the battery.

e)Ensure that the output current of the DC/DC converter is below the allowed charging current of the battery.

f)

The return current to the DC/DC converter (battery discharge current) is typ. 15mA when the DC/DC converter is switched off(except in case a blocking diode is utilized).

22.5. EXTERNAL INPUT PROTECTION
The unit is tested and approved for branch circuits up to 50A. An external protection is only required, if the supplying branch has anampacity greater than this. Check also local codes and local requirements. In some countries local regulations might apply.
If an external fuse is necessary or utilized, minimum requirements need to be considered to avoid nuisance tripping of the circuit
breaker. A minimum value of 10A B- or 8A C-Characteristic breaker should be used.

22.6. REQUIREMENTS FOR THE SUPPLYING SOURCE
In certain circumstances, the input filter of the DC/DC converter can show a resonant effect which is caused by the supplying network.
Especially when additional external input filters are utilized, a superimposed AC voltage can be generated on the input terminals of the
DC/DC converter which might cause a malfunction of the unit. Therefore, additional input filters are not recommended. To avoid theresonant effects, the minimal resistance of the supplying network which depends on the inductance of the input network, shall be
above the boundary curve in Fig. 22-3.
Fig. 22-3 External input filter requirements to avoid filter
instabilities
Resistance of the
supplying network

1 Ohm
(a)
(b)

100 mOhm
10 mOhm(a) max.
(b) typ.

1 mOhm
0.1mH

1mH

10mH

Inductance of the supplying network

Apr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

24/27

CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

22.7. PARALLEL USE TO INCREASE OUTPUT POWER
The DC/DC-converter can be paralleled to increase the output power. There are no featureincluded which balances the load current between the DC/DC-converters. Therefore some
restrictions and limitations apply. The DC/DC-converter with the higher adjusted output
voltage draws current until it goes into current limitation. This means no harm or switch-off
to this DC/DC-converter as long as the ambient temperature stays below 45°C. The CD5.121
can also be paralleled with power supplies from the QS10.121 from the DIMENSION QSseries. For other power supplies consult PULS.

Unit A
Input+-

OutputUnit B
Input

Load

+
+
-

The output voltages of all DC/DC-converters shall be adjusted to the same value (±100mV) at
Outputfull load. A fuse or diode on the output of each unit is only required if more than three units
are connected in parallel. This avoid that more than 2 times of the nominal output current can flow backwards into the DC/DC converterin case the output stage of one DC/DC converter has a defect. If a fuse (or circuit breaker) is used, choose one with approximately 150%of the rated output current of one DC/DC-converter. Keep an installation clearance of 15mm (left / right) between two DC/DCconverters and avoid installing the DC/DC-converters on top of each other. Do not use DC/DC-converters in parallel in mounting
orientations other than the standard mounting orientation (input terminals on the bottom and output terminals on top of the unit).

22.8. PARALLEL USE FOR REDUNDANCYThe DC/DC converters can be paralleled for 1+1 redundancy to gain higher system availability. Redundant systems require a certain
amount of extra power to support the load in case one DC/DC converter fails. The simplest way is to put two DC/DC converters inparallel. This is called a 1+1 redundancy. In case one DC/DC converter fails, the other one is automatically able to support the load
current without any interruption. Redundant systems for a higher power demand are usually built in an N+1 method. E.g. six DC/DC
converters, each rated for 8A are paralleled to build a 40A redundant system.
Furthermore, 1+1 redundant systems can be built by using a DC/DC converter powered from a battery and a power supply with AC
input.
Please note: This simple way to build a redundant system does not cover failures such as an internal short circuit in the secondary sideof the DC/DC-converter. In such a case, the defect unit becomes a load for the other DC/DC-converters and the output voltage can not
be maintained any more. This can only be avoided by utilizing decoupling diodes which are included in the decoupling module
YR2.DIODE.
Recommendations for building redundant power systems:a)

Use separate input fuses for each DC/DC-converter.

b)

Monitor the individual DC/DC-converter units.

c)

1+1 Redundancy is allowed up to an ambient temperature of 60°C
N+1 Redundancy is allowed up to an ambient temperature of 45°Cd)

It is desirable to set the output voltages of all units to the same value (± 100mV) or leave it at the factory setting.

Apr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

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CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

22.9. DAISY CHAINING OF OUTPUTS
Daisy chaining (jumping from one DC/DC-converter output to the next) is allowed as long as the average output current through one
terminal pin does not exceed 25A. If the current is higher, use a separate distribution terminal block.
Fig. 22-4 Daisy chaining of outputs

Fig. 22-5 Using distribution terminals

max 25A!

Output+ + - -

Output+ + - -

DC/DC
Converter
Input

+

-

Output+ + - -

Output+ + - -

DC/DC
Converter

DC/DC
Converter

DC/DC
Converter

Input

Input

Input

Load

+

-

Load

Distribution
Terminals

22.10. SERIES OPERATION

Unit A

DC/DC converters of the exact same type can be connected in series for higher output
voltages. It is possible to connect as many units in series as needed, providing the sum of theoutput voltage does not exceed 150Vdc. Voltages with a potential above 60Vdc are not SELV
any more and can be dangerous. Such voltages must be installed with a protection against
touching. Earthing of the output is required when the sum of the output voltage is above
60Vdc. Avoid return voltage (e.g. from a decelerating motor or battery) which is applied tothe output terminals. Keep an installation clearance of 15mm (left / right) between two
DC/DC-converters and avoid installing the DC/DC-converters on top of each other. Do not use
DC/DC-converters in series in mounting orientations other than the standard mounting
orientation (input terminals on the bottom and output terminals on top of the unit).

Input

+
-

OutputUnit B
Input+

Output

Load

+
-

-

22.11. USE IN A TIGHTLY SEALED ENCLOSURE
When the DC/DC-converter is installed in a tightly sealed enclosure, the temperature inside the enclosure will be higher than outside. In
such situations, the inside temperature defines the ambient temperature for the DC/DC-converter.
The following measurement results can be used as a reference to estimate the temperature rise inside the enclosure.
The DC/DC-converter is placed in the middle of the box, no other heat producing items are inside the box
Enclosure:
Load:
Input:
Temperature inside enclosure:
Temperature outside enclosure:
Temperature rise:

Rittal Typ IP66 Box PK 9516 100, plastic, 110x180x165mm
12V, 6.4A; (=80%) load is placed outside the box
24Vdc
48.0°C (in the middle of the right side of the DC/DC converter with a distance of 2cm)
22.6°C
25.4K

Apr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
www.pulspower.com Phone +49 89 9278 0 Germany

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CD5.121
DC/DC Converter 12V, 8A, 96W

CD-Series

22.12. MOUNTING ORIENTATIONSMounting orientations other than input terminals on the bottom and output on the top require a reduction in continuous output power
or a limitation in the max. allowed ambient temperature. The amount of reduction influences the lifetime expectancy of the DC/DC
converter. Therefore, two different derating curves for continuous operation can be found below:
Curve A1
Curve A2

Recommended output current.
Max allowed output current (results in approximately half the lifetime expectancy of A1).

Fig. 22-6
Mounting
Orientation A(Standardorientation)

Output Current

OUTPUT

10A
8
6
4
2
0

DC/DC
Converter
INPUT

A1

Ambient Temperature

10
Fig. 22-7
Mounting
Orientation B(Upside down)

INPUT

10A
8
6
4
2
0

DC/DC
Convert er
OUTPUT
Fig. 22-8
Mounting
Orientation C(Table-top
mounting)

40

50

60°C

A2
A1
Ambient Temperature

20

30

40

50

60°C

Output Current

10A
8
6
4
2
0

A2
A1
Ambient Temperature

10

20

30

40

50

60°C

Output Current

OUTPUT

DC/DC
Convert er

INPUT

10A
8
6
4
2
0

A2
A1
Ambient Temperature

10

20

30

40

50

60°C

INPUT

DC/DC
Convert er

Output Current

OUTPUT

Fig. 22-10
Mounting
Orientation E(Horizontal ccw)

30

Output Current

10

Fig. 22-9
Mounting
Orientation D(Horizontal cw)

20

10A
8
6
4
2
0

A2
A1
Ambient Temperature

10

20

30

40

50

60°C

Apr. 2023 / Rev. 1.9 DS-CD5.121-EN
All parameters are specified at 12V, 8A, 24Vdc input voltage, 25°C ambient and after a 5 minutes run-in time unless otherwise noted.
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