UCR100-240-T72-V-C - Murata Power Solutions

OBSOLETE PRODUCT

Housed in a 3U x 4TE x 165.5 mm extruded

aluminum cassette module suitable for 19-inch

rack mounting, the UCR series of isolated 100

Watt DC-DC converters provide clean DC output

power over a very wide input voltage range. The

standard input range is 16.8 to 137.5 Volts DC

with transient capability between 14.4V and 154V.

The reverse-polarity protected input is immune to

surges and transients per EN50155, IEC60571 and

RIA12 standards. The double reinforced insulation

system protects over the full power and tempera-

ture range in compliance with IEC/EN/UL60950-1

and EN50116. The UCR series is ideal for battery

and mobile distributed power applications in

transportation, industrial, vehicles, signal systems,

communications and railways.

The ﬁ xed output voltage is fully regulated with

excellent noise, ripple and transient settling char-

acteristics. Isolation characteristics are 2250 Volts

DC (1500 VAC) input to output and input to case.

The ruggedized 3U housing features conformal

coating of internal components for moisture resis-

tance. The high efﬁ ciency design requires no forced

cooling since all internal power dissipation is

routed to integral extruded aluminum chassis rails.

The enclosure may also be mounted against a cold

plate inside a sealed chassis in conduction cooling

applications. The UCR series is designed to comply

with numerous environmental, EMC/EMI and safety

standards (see speciﬁ cations). Protection systems

include output overcurrent and short circuit, over

temperature shutdown (with automatic recovery)

and output overvoltage. An industry-standard DIN

H15 rear connector is used.

All models are equipped with an On/Off control,

sense inputs, and output voltage trim (±10 %).

Optional features include output OK LED lamp and

control signal, active current sharing with other UCR’s,

external capacitor for extended hold-up time, and

adjustable input undervoltage lockout.

PRODUCT OVERVIEWFEATURES

 16.8 to 137.5 VDC wide input voltage range

 Fixed 5.1, 12 or 24VDC unipolar output up to

120 Watts

 3U x 4TE x 165.5mm (111 x 20.3 x 165.5 mm)

cassette module for 19-inch rack mounting

 Ruggedized “no fans” high reliability enclosure

with conformal coated components

 Extensive self-protection, over temperature and

short circuit features

 On/Off control, sense, current share, output OK

LED, UV lockout, Hold-up Cap and trim (some

functions optional)

 Adjustable input undervoltage (UVLO) protection,

optional

 2250VDC/1500VAC I/O isolation plus RoHS-6

compliance

 Operating temperature range -40 to +85˚

Celsius

 Extensive EU transportation and railway stand-

ards adherence

Typical unit

Figure 1. UCR Block Diagram

Murata Power Solutions

recommends an external fuse,

F1. See page 17 for details.

On/Off

Primary

Control

Circuitry Feedback

Circuit

Primary

Switches

Input

Filter

Output

Filter

Isolation

Not connected

*Please see ordering guide for optional features

CyCy

Secondary

Control

Circuitry

Secondary

Synchronous

Rectiﬁers

+H-UP CAP

UVLO Trim

+Vin

+Vout

-Vout

-Sense

+Sense

Trim

Current Share*

+Vout OK or H-UP *

-Vout OK or UVLO *

-Vin

External

Power

Source

UCR100 Series

3U High Reliability DC-DC Converters

MDC_UCR100.C02 Page 1 of 20

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For full details go to

www.murata-ps.com/rohs

PART NUMBER STRUCTURE

Nominal Output Voltage

050 = 5.1Vdc

120 = 12Vdc

240 = 24Vdc

Output Power1

Series

Nominal Input Voltage Range

T72 = 16.8V-137.5Vdc

Option Package

Blank = Standard option (remote on/off, remote sense, I/O OK LED indicator and Vout Trim)

S = Standard option plus current sharing² and Vout OK signals

V = Standard option plus Hold-up connection³ and UVLO

SV = Standard option plus current sharing,² Hold-up and UVLO

¹Please refer to the wattage rating in the Ordering Guide section of the data sheet.

²Current sharing is not available on the 24V output models.

³External capacitor is required.

UCR 100 120---T72 SV C-

RoHS-6/6 Compliant

PERFORMANCE SPECIFICATIONS SUMMARY AND ORDERING GUIDE

Root Model

Number ➀

Output Input Efﬁ ciency Dimensions

Vout

(Volts DC)

Iout

(Amps,max.)

Power

(Watts)

R/N (mV p-p) Regulation (max.) Vin nom.

(Volts DC)

Range

(Volts) ➂

Pwr, no

load (W)

Iin, full load

(Amps) ➁

Typ. Max. Line Load Min. Typ. Inches mm

UCR100-050-T72-C 5.1 20 100 20 80 ±0.25% ±0.25% 72 16.8-137.5 3 1.61 85.0% 87% 4.38x0.81x6.52 111x20.3x165.5

UCR100-120-T72-C 12 10 120 50 75 ±0.25% ±0.25% 72 16.8-137.5 3.5 1.99 84.5% 86.5% 4.38x0.81x6.52 111x20.3x165.5

UCR100-240-T72-C 24 5.5 132 100 150 ±0.25% ±0.25% 72 16.8-137.5 3.5 2.11 88% 90% 4.38x0.81x6.52 111x20.3x165.5

➀ These are not complete model numbers. Please refer to the Part Number Structure for ordering

information of all options.

➁ Measured at nominal line voltage and max load, +25°C ambient temperature, sense lines

connected.

➂ This is the standard input range. The transient input range (0.1 seconds) is 14.4V to 154V.

UCR100 Series

3U High Reliability DC-DC Converters

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TABLE 1. OPTIONS

PART NUMBER CURRENT SHARE UVLO HOLD-UP Vout OK

UCR100-050-T72-C

UCR100-050-T72-S-C ✓ ✓

UCR100-050-T72-SV-C ✓✓✓

UCR100-050-T72-V-C ✓✓

UCR100-120-T72-C

UCR100-120-T72-S-C ✓ ✓

UCR100-120-T72-SV-C ✓✓✓

UCR100-120-T72-V-C ✓✓

UCR100-240-T72-C

UCR100-240-T72-V-C ✓✓

FUNCTIONAL SPECIFICATIONS, UCR100-050-T72 ➀

INPUT Conditions/Comments Minimum Typical/Nominal Maximum Units

Operating voltage range, standard 16.8 72 137.5 Vdc

Surge and Transient Protection Per EN50155, IEC60571 and RIA12

Input Limits, no damage Operating or non-operating 0 154 Vdc

Input Filter Per EN50155, Symmetrical combined with

VDR/transorb

Reverse Polarity Protection Yes, in conjunction with external fuse. Vdc

Start-up threshold 12.8 14.6 16.4 Vdc

Undervoltage shutdown ➁50% load 10.5 12.3 14.0 Vdc

Overvoltage shutdown 50% load 170 Vdc

Input current/power

Full Load Current 1.30 1.67 Amps

Peak Inrush Current 40 Amps

Short Circuit Input Current 0.05 0.1 Amps

No Load Input Power Iout = minimum 3.0 3.5 Watts

Low Line Input Current Vin = minimum 5.89 7.57 Amps

Shutdown Mode Input Current 510mA

Reﬂ ected (back) ripple current ➂5 10 mA pk-pk

GENERAL and SAFETY

Efﬁ ciency Vin = nom., 16A load 85 87 %

Vin = 110V, 16A load 85 86.5 %

Vin = 24V, 16A load 81 82.5 %

Switching Frequency 90 100 110 KHz

Turn-On Time Vin on to Vout regulated 150 160 mS

Remote ON to Vout regulated 150 160 mS

Isolation Voltage Input to output, case and aux. test 2250 Vdc

Isolation Voltage Case to output and Aux. test voltage 2250 Vdc

Subassemblies pre-tested per EN50116/60950 4200 Vdc

Isolation Safety Rating Based on 250 VAC or 240 VDC I/O Double/Reinforced

Isolation Resistance 100 Mohm

Isolation Capacitance 4000 pF

Safety (Designed to meet the following

requirements)

UL-60950-1, (2nd Edition), CSA-C22.2

No.60950-1, IEC/EN60950-1 Yes

Calculated MTBF per MIL-HDBK-217F

Ground benign, Tcase = 40˚C TBC Hours

Ground benign, Tcase = 40/70˚C TBC Hours

Ground benign, Tcase = 50˚C TBC Hours

OUTPUT

Total Output Power Full temperature range 0.0 81.6 103.02 Watts

Voltage

Output Voltage Range Vout = nominal 5.049 5.1 5.151 Vdc

Setting Accuracy 50% load ±1 % of Vnom.

Overvoltage Protection magnetic feedback 5.9 6.2 6.5 Vdc

Vout Adjustment Range <optional> -10 10 % of Vnom.

Current

Output Current Range Vin = 16.8-137.5V. 0.0 16 20 Amps

Current Limit Inception 98% of Vnom., after warmup 24 26.35 28.70 Amps

Short Circuit Current Hiccup technique, autorecovery within ±1%

of Vout 0.5 1 Amps

Short Circuit Duration Output shorted to ground Continuous

Short circuit protection method Current limiting, hiccup autorestart

Line Regulation Vin = min. to max. ±0.25 % of Vnom.

Vout = nom.

Load Regulation Iout = min. to max. ±0.25 % of Vnom.

Dynamic Load Response 50-75-50% load step 75 150 µSec

settling time to within ±1% of Vout

Peak deviation ±200 ±250 mV

Ripple and Noise, 1 & 10 µF output 5 Hz- 20 MHz BW 20 80 mV pk-pk

Temperature Coefﬁ cient At all outputs ±0.02 % of Vnom./°C

Maximum Output Capacitance ESR 0.02 min., resistive load 6600 F

Notes

➀ Unless otherwise noted, units are speciﬁ ed with 1µF ceramic and 10µF tantalum

external output capacitors in parallel (low ESR). The external input capacitor is 33µF,

low ESR.

➁ Undervoltage shutdown is also available as a user-adjustable option.

➂ Back ripple current input ﬁ lter is Cin=33µF, Cbus=220µF, Lbus=12µH

➃ Remove overload for recovery

➄ Output may be shorted to ground with no damage.

UCR100 Series

3U High Reliability DC-DC Converters

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FUNCTIONAL SPECIFICATIONS, UCR100-120-T72 ➀

INPUT Conditions/Comments Minimum Typical/Nominal Maximum Units

Operating voltage range, standard 16.8 72 137.5 Vdc

Surge and Transient Protection Per EN50155, IEC60571 and RIA12

Input Limits, no damage Operating or non-operating 0 154 Vdc

Input Filter Per EN50155, Symmetrical combined with

VDR/transorb

Reverse Polarity Protection Yes, in conjunction with external fuse Vdc

Start-up threshold 11.5 15.0 16.3 Vdc

Undervoltage shutdown ➁50% load 10.3 12 14.8 Vdc

Overvoltage shutdown 50% load 170 Vdc

Input current/power

Full Load Current 1.54 1.99 Amps

Peak Inrush Current 40 Amps

Short Circuit Input Current 0.05 0.1 Amps

No Load Input Power Iout = minimum 3.5 4.5 Watts

Low Line Input Current Vin = minimum 7.05 9.37 Amps

Shutdown Mode Input Current 510mA

Reﬂ ected (back) ripple current ➂5 10 mA pk-pk

GENERAL and SAFETY

Efﬁ ciency Vin = nom., 8A load 84.5 86.5 %

Vin = 110V, 8A load 86 87.5 %

Vin = 24V, 8A load 77 81 %

Switching Frequency 90 100 110 KHz

Turn-On Time Vin on to Vout regulated 150 160 mS

Remote ON to Vout regulated 150 160 mS

Isolation Voltage Input to output, case and aux. test 2250 Vdc

Isolation Voltage Case to output and Aux. test voltage 2250 Vdc

Subassemblies pre-tested per EN50116/60950 4200 Vdc

Isolation Safety Rating Based on 250 VAC or 240 VDC I/O Double/Reinforced

Isolation Resistance 100 Mohm

Isolation Capacitance 4000 pF

Safety (Designed to meet the following

requirements)

UL-60950-1, (2nd Edition), CSA-C22.2

No.60950-1, IEC/EN60950-1 Yes

Calculated MTBF per MIL-HDBK-217F

Ground benign, Tcase = 40˚C TBC Hours

Ground benign, Tcase = 40/70˚C TBC Hours

Ground benign, Tcase = 50˚C TBC Hours

OUTPUT

Total Output Power Full temperature range 0.0 96 121.2 Watts

Voltage

Output Voltage Range Vout = nominal 11.88 12.0 12.12 Vdc

Setting Accuracy 50% load ±1 % of Vnom.

Overvoltage Protection magnetic feedback 13.5 14.4 15 Vdc

Vout Adjustment Range <optional> -10 10 % of Vnom.

Current

Output Current Range Vin = 16.8-137.5V. 0.0 8.0 10.0 Amps

Current Limit Inception 98% of Vnom., after warmup 14 16 18 Amps

Short Circuit Current Hiccup technique, autorecovery within ±1%

of Vout 0.5 1 Amps

Short Circuit Duration Output shorted to ground Continuous

Short circuit protection method Current limiting, hiccup autorestart

Line Regulation Vin = min. to max. ±0.25 % of Vnom.

Vout = nom.

Load Regulation Iout = min. to max. ±0.25 % of Vnom.

Dynamic Load Response 50-75-50% load step 100 200 µSec

settling time to within ±1% of Vout

Peak deviation ±200 ±250 mV

Ripple and Noise, 1 & 10 F output capacitors 5 Hz- 20 MHz BW 50 75 mV pk-pk

Temperature Coefﬁ cient At all outputs ±0.02 % of Vnom./°C

Maximum Output Capacitance ESR 0.02 min., resistive load 3300 F

Notes

➀ Unless otherwise noted, units are speciﬁ ed with 1µF ceramic and 10µF tantalum

external output capacitors in parallel (low ESR). The external input capacitor is 33µF,

low ESR.

➁ Undervoltage shutdown is also available as a user-adjustable option.

➂ Back ripple current input ﬁ lter is Cin=33µF, Cbus=220µF, Lbus=12µH

➃ Remove overload for recovery

➄ Output may be shorted to ground with no damage.

UCR100 Series

3U High Reliability DC-DC Converters

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FUNCTIONAL SPECIFICATIONS, UCR100-240-T72 ➀

INPUT Conditions/Comments Minimum Typical/Nominal Maximum Units

Operating voltage range, standard 16.8 72 137.5 Vdc

Surge and Transient Protection Per EN50155, IEC60571 and RIA12

Input Limits, no damage Operating or non-operating 0 154 Vdc

Input Filter Per EN50155, Symmetrical combined with

VDR/transorb

Reverse Polarity Protection Supplied standard Yes Vdc

Start-up threshold 11.5 13.9 16.3 Vdc

Undervoltage shutdown ➁50% load 10.5 12.7 14.8 Vdc

Overvoltage shutdown 50% load 170 Vdc

Input current/power

Full Load Current 1.63 2.11 Amps

Peak Inrush Current 40 Amps

Short Circuit Input Current 0.25 0.35 Amps

No Load Input Power Iout = minimum 3.5 4.5 Watts

Low Line Input Current Vin = minimum 7.76 10.09 Amps

Shutdown Mode Input Current 510mA

Reﬂ ected (back) ripple current ➂5 10 mA pk-pk

GENERAL and SAFETY

Efﬁ ciency Vin = nom., 4.4A load 88 90 %

Vin = 110V, 4.4A load 86.5 88.5 %

Vin = 24V, 4.4A load 79 81 %

Switching Frequency 90 100 110 KHz

Turn-On Time Vin on to Vout regulated 150 160 mS

Remote ON to Vout regulated 150 160 mS

Isolation Voltage Input to output, case and aux. test 2250 Vdc

Isolation Voltage Case to output and Aux. test voltage 2250 Vdc

Subassemblies pre-tested per EN50116/60950 4200 Vdc

Isolation Safety Rating Based on 250 VAC or 240 VDC I/O Double/Reinforced

Isolation Resistance 100 Mohm

Isolation Capacitance 4000 pF

Safety (Designed to meet the following

requirements)

UL-60950-1, (2nd Edition), CSA-C22.2

No.60950-1, IEC/EN60950-1 Yes

Calculated MTBF per MIL-HDBK-217F

Ground benign, Tcase = 40˚C TBC Hours

Ground benign, Tcase = 40/70˚C TBC Hours

Ground benign, Tcase = 50˚C TBC Hours

OUTPUT

Total Output Power Full temperature range 0.0 105.6 133.98 Watts

Voltage

Output Voltage Range Vout = nominal 23.64 24.0 24.36 Vdc

Setting Accuracy 50% load ±1.5 % of Vnom.

Overvoltage Protection magnetic feedback 27 28.5 30 Vdc

Vout Adjustment Range <optional> -10 10 % of Vnom.

Current

Output Current Range Vin = 16.8-137.5V. 0.0 4.4 5.5 Amps

Current Limit Inception 98% of Vnom., after warmup 6.5 7.75 9.5 Amps

Short Circuit Current Hiccup technique, autorecovery within ±1%

of Vout 0.5 1 Amps

Short Circuit Duration Output shorted to ground Continuous

Short circuit protection method Current limiting, hiccup autorestart

Line Regulation Vin = min. to max. ±0.25 % of Vnom.

Vout = nom.

Load Regulation Iout = min. to max. ±0.25 % of Vnom.

Dynamic Load Response 50-75-50% load step 100 200 µSec

settling time to within ±1% of Vout

Peak deviation ±200 ±250 mV

Ripple and Noise, 1 & 10 µF output 5 Hz- 20 MHz BW 100 150 mV pk-pk

Temperature Coefﬁ cient At all outputs ±0.02 % of Vnom./°C

Maximum Output Capacitance ESR 0.02 min., resistive load 1200 F

Notes

➀ Unless otherwise noted, units are speciﬁ ed with 1µF ceramic and 10µF tantalum

external output capacitors in parallel (low ESR). The external input capacitor is 33µF,

low ESR.

➁ Undervoltage shutdown is also available as a user-adjustable option.

➂ Back ripple current input ﬁ lter is Cin=33µF, Cbus=220µF, Lbus=12µH

➃ Remove overload for recovery

➄ Output may be shorted to ground with no damage.

UCR100 Series

3U High Reliability DC-DC Converters

MDC_UCR100.C02 Page 5 of 20

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FEATURES and OPTIONS Conditions/Comments Minimum Typical/Nominal Maximum Units

Remote On/Off Control Negative logic

Unit is OFF Pin open or external voltage 2.5 50 Vdc

Unit is ON -0.5 0.8 Vdc

Shutdown Current Open collector/drain 1 2 mA

Remote Sense Sense pins connected externally to respective

Vout's 10 %

Vout trim -10 +10 % of Vout

Pre-biased startup External voltage < Vset Monotonic

Isolated Vout "OK" Signal <optional> (“S” sufﬁ x)

Vout ready (LO) Iok < 0.5 mA 0.8 1.0 Vdc

Vout fail (HI) External Vok < 15V. 25 µA

Current Share <optional> “S” or “SV” sufﬁ x ±20 % of Iout

External Cap Hold-up Time <“V” or “SV” sufﬁ x> See Hold-up Time note 10 mS

Input Undervoltage Lockout

<“V” or “SV” sufﬁ x> See Input Undervoltage Lockout note

MECHANICAL

Outline Dimensions 4.38x0.81x6.52 Inches

please refer to Mechanical Speciﬁ cations 111x20.3x165.5 mm

Weight: UCR100-050-T72, UCR100-120-T72 18 Ounces

510 Grams

Weight: UCR100-240-T72 21 Ounces

595 Grams

Case Material Aluminum

Rear Connector P87 pinout, per DIN41612 H15

EMI/RFI Shielding Provided by case

ENVIRONMENTAL

Operating Ambient Temperature Range See Performance Data for

temperature derating curves -40 71 °C

Absolute Operating Temperature Range With derating -40 95 °C

Storage Temperature Vin = Zero (no power) -55 125 °C

Thermal Protection/Shutdown Measured at case center 105 110 120 °C

Electromagnetic Interference (pending)

Conducted, EN55022/CISPR22 Measure within 19" rack

Radiated, EN55022/CISPR22

Relative humidity, non-condensing To +85°C/85%

ABSOLUTE MAXIMUM RATINGS

Input Voltage, Transient Operating or non-operating, 100 mS max. 0 154 Vdc

Input Reverse Polarity Yes Vdc

On/Off Control Power on or off, referred to -Vin -0.5 50 Vdc

Storage Temperature Range Vin = Zero (no power) -55 125 °C

Notes

➀ Unless otherwise noted, units are speciﬁ ed with 1µF ceramic and 10µF tantalum

external output capacitors in parallel (low ESR). The external input capacitor is 33µF,

low ESR.

➁ Undervoltage shutdown is also available as a user-adjustable option.

➂ Back ripple current input ﬁ lter is Cin=33µF, Cbus=220µF, Lbus=12µH

➃ Remove overload for recovery

➄ Output may be shorted to ground with no damage.

FUNCTIONAL SPECIFICATIONS FOR ALL MODELS, CONTINUED

UCR100 Series

3U High Reliability DC-DC Converters

MDC_UCR100.C02 Page 6 of 20

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PERFORMANCE DATA, UCR100-050-T72-C

Output Voltage Vs. Input Line Voltage and Output Load Current

Power Dissipation vs. Load Current @ Ta = +25°CEfﬁ ciency vs. Line Voltage and Load Current @ Ta = +25°C

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Load Current (Amps)

Efﬁciency (%)

Vin = 24V

Vin = 36V

Vin = 48V

Vin = 60V

Vin = 72V

Vin = 96V

Vin = 110V

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Vin = 24V

Vin = 36V

Vin = 48V

Vin = 60V

Vin = 72V

Vin = 96V

Vin = 110V

Output Load Current (Amps)

Power Dissipation (Watts)

5.122

5.124

5.126

5.128

5.13

5.132

5.134

5.136

5.138

5.14

5.142

1 2 3 4 5 6 7 8 9 1011121314151617181920

Vin = 24V

Vin = 36V

Vin = 48V

Vin = 60V

Vin = 72V

Vin = 96V

Vin = 110V

Output Load Current (Amps)

Output Voltage (Volts)

Maximum Power Temperature Derating at Sea Level

Natural Convection

Maximum Power Temperature Derating at Sea Level

100 LFM (air ﬂ ow from Rear Panel to Input Conn.)

100

105

110

30 35 40 45 50 55 60 65 70 75 80 85

Output Power (Watts)

Ambient Temperature (ºC)

Vin = 24 V

Vin = 36 V

Vin = 48 V

Vin = 60 V

Vin = 72 V to 137.5 V

100

105

110

30 35 40 45 50 55 60 65 70 75 80 85

Output Power (Watts)

Ambient Temperature (ºC)

Vin = 24 V

Vin = 36 V

Vin = 48 V

Vin = 60 V

Vin = 72 V to 137.5 V

UCR100 Series

3U High Reliability DC-DC Converters

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PERFORMANCE DATA, UCR100-050-T72-C

On/Off Enable Start-up (Vin=72V, Vout=nom, Iout=20A, Cload=8000uF,

Ta=+25°C) Trace1=Vin, Trace 2=Vout.

Start-up Delay (Vin=72V, Vout=nom, Iout=20A, Cload=8000uF, Ta=+25°C)

Trace1=Vin, Trace 2=Vout.

Output Ripple and Noise (Vin=72V, Iout=20A, Cload= 10uF || 1uF, Ta=+25°C)Step Load Transient Response (Vin=72V, Vout=nom, Cload= 10uF || 1uF,

Iout=50-75-50% of full load (Iout=10A/Div), Ta=+25°C)

UCR100 Series

3U High Reliability DC-DC Converters

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PERFORMANCE DATA, UCR100-120-T72-C

Output Voltage Vs. Input Line Voltage and Output Load Current

Power Dissipation vs. Load Current @ Ta = +25°CEfﬁ ciency vs. Line Voltage and Load Current @ Ta = +25°C

12345678910

Load Current (Amps)

Efﬁciency (%)

Vin = 24V

Vin = 36V

Vin = 48V

Vin = 60V

Vin = 72V

Vin = 96V

Vin = 110V

12345678910

Vin = 24V

Vin = 36V

Vin = 48V

Vin = 60V

Vin = 72V

Vin = 96V

Vin = 110V

Output Load Current (Amps)

Power Dissipation (Watts)

12345678910

11.97

11.972

11.974

11.976

11.978

11.98

11.982

11.984

11.986

11.988

11.99

Vin = 24V

Vin = 36V

Vin = 48V

Vin = 60V

Vin = 72V

Vin = 96V

Vin = 110V

Output Load Current (Amps)

Output Voltage (Volts)

Maximum Power Temperature Derating at Sea Level

Natural Convection

Maximum Power Temperature Derating at Sea Level

100 LFM (air ﬂ ow from Rear Panel to Input Conn.)

100

105

110

115

120

125

30 35 40 45 50 55 60 65 70 75 80 85

Output Power (Watts)

Ambient Temperature (ºC)

Vin = 24 V

Vin = 36 V

Vin = 48 V

Vin = 60 V

Vin = 72 V

Vin = 96 V

Vin = 110 V

100

105

110

115

120

125

30 35 40 45 50 55 60 65 70 75 80 85

Output Power (Watts)

Ambient Temperature (ºC)

Vin = 24 V

Vin = 36 V

Vin = 48 V

Vin = 60 V

Vin = 72 V

Vin = 96 V

Vin = 110 V

UCR100 Series

3U High Reliability DC-DC Converters

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PERFORMANCE DATA, UCR100-120-T72-C

On/Off Enable Start-up (Vin=72V, Vout=nom, Iout=10A, Cload=3300uF,

Ta=+25°C) Trace1=Vin, Trace 2=Vout.

Start-up Delay (Vin=72V, Vout=nom, Iout=10A, Cload=4700uF, Ta=+25°C)

Trace1=Vin, Trace 2=Vout.

Output Ripple and Noise (Vin=72V, Iout=10A, Cload= 10uF || 1uF, Ta=+25°C)Step Load Transient Response (Vin=72V, Vout=nom, Cload= 10uF || 1uF,

Iout=50-75-50% of full load (Iout=5A/Div), Ta=+25°C)

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3U High Reliability DC-DC Converters

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PERFORMANCE DATA, UCR100-240-T72-C

Output Voltage Vs. Input Line Voltage and Output Load Current

Power Dissipation vs. Load Current @ Ta = +25°CEfﬁ ciency vs. Line Voltage and Load Current @ Ta = +25°C

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5

Load Current (Amps)

Efﬁciency (%)

Vin = 24V

Vin = 36V

Vin = 48V

Vin = 60V

Vin = 72V

Vin = 96V

Vin = 110V

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5

Vin = 24V

Vin = 36V

Vin = 48V

Vin = 60V

Vin = 72V

Vin = 96V

Vin = 110V

Output Load Current (Amps)

Power Dissipation (Watts)

23.99

23.995

24.005

24.01

24.015

24.02

24.025

24.03

24.035

24.04

0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5

Vin = 24V

Vin = 36V

Vin = 48V

Vin = 60V

Vin = 72V

Vin = 96V

Vin = 110V

Output Load Current (Amps)

Output Voltage (Volts)

Maximum Power Temperature Derating at Sea Level

Natural Convection

Maximum Power Temperature Derating at Sea Level

100 LFM (air ﬂ ow from Rear Panel to Input Conn.)

100

105

110

115

120

125

130

135

140

30 35 40 45 50 55 60 65 70 75 80 85

Output Power (Watts)

Ambient Temperature (ºC)

Vin = 24 V

Vin = 36 V

Vin = 48 V

Vin = 60 V to 137.5 V

100

105

110

115

120

125

130

135

140

30 35 40 45 50 55 60 65 70 75 80 85

Output Power (Watts)

Ambient Temperature (ºC)

Vin = 24 V

Vin = 36 V

Vin = 48 V

Vin = 60 V to 137.5 V

UCR100 Series

3U High Reliability DC-DC Converters

MDC_UCR100.C02 Page 11 of 20

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PERFORMANCE DATA, UCR100-240-T72-C

On/Off Enable Start-up (Vin=72V, Vout=nom, Iout=5.5A, Cload=1200uF,

Ta=+25°C) Trace1=Vin, Trace 2=Vout.

Start-up Delay (Vin=72V, Vout=nom, Iout=5.5A, Cload=1200uF, Ta=+25°C)

Trace1=Vin, Trace 2=Vout.

Output Ripple and Noise (Vin=72V, Iout=5.5A, Cload= 10uF || 1uF, Ta=+25°C)Step Load Transient Response (Vin=72V, Vout=nom, Cload= 10uF || 1uF,

Iout=50-75-50% of full load (Iout=2A/Div), Ta=+25°C)

UCR100 Series

3U High Reliability DC-DC Converters

MDC_UCR100.C02 Page 12 of 20

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MECHANICAL SPECIFICATIONS

UCR100 Series

3U High Reliability DC-DC Converters

MDC_UCR100.C02 Page 13 of 20

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TABLE 2. PIN ALLOCATION

Pin Function Standard Option "S" Option "V" Option "SV"

4 Output Voltage (positive) +Vout +Vout +Vout +Vout

6 Output Voltage (positive) +Vout +Vout +Vout +Vout

8 Output Voltage (negative) -Vout -Vout -Vout -Vout

10 Output Voltage (negative) -Vout -Vout -Vout -Vout

12 Remote Sense (positive)* +Sense +Sense +Sense +Sense

14 Remote Sense (negative)* -Sense -Sense -Sense -Sense

16 Output Voltage Trim Trim Trim Trim Trim

18 Current Share NA*** Current Share NA*** Current Share

20 Not Connected NC NC NC NC

22 + Vout OK / Hold-up NC +Vout OK H-UP H-UP

24 - Vout OK / UVLO NC -Vout OK UVLO UVLO

26 Protective Earth* PE PE PE PE

28 Remote On/Off** On/Off On/Off On/Off On/Off

30 Input Voltage (positive) +Vin +Vin +Vin +Vin

32 Input Voltage (negative) -Vin -Vin -Vin -Vin

* Leading pin (connect ﬁ rst, break last)

** Connect to -Vin if not used

*** Pin is disconnected internally

Figure 2. Case C90

Figure 3. Rear connector detail

Pinout P87

20.3

(TE)

15.2

5.1

111.0

(4.37) 100.0

(3.94)

10.2

5.5

(0.22)

100.0

(3.94)

7.0

Conn

BACK

PLATE

LSlide

19.8

(0.78)

111.0

(4.37)

ISOMETRIC

TOP

MAIN FACE

171.9

(6.77)

5.9

(0.23)

FRONT

PLATE

LSlide

4 TE Module Slot

(REF ONLY)

REAR FACE

165.5

(6.52)

(4 Places)

M3x0.5

6mm DEEP

104.0

(4.09)

127.0

(5.00)

19.5

(0.77)

172.9

(6.81) REF

30 26 22 18 14 10 6

32 28 24 20 16 12 8 4

Third Angle Projection

Dimensions are in mm (inches shown for ref. only).

Components are shown for reference only.

Tolerances (unless otherwise speciﬁed):

.XX ± 0.02 (0.5)

.XXX ± 0.010 (0.25)

Angles ± 1˚

When using units with the load share option in stand-alone operation

with the remote sense feature, the load share pin must be connected

to -Vout. This does not apply if the remote sense lines are connected

directly at the connector.

SHIPPING TRAYS AND BOXES (3 TRAYS PER CARTON, 6 UNITS PER CARTON)

SHIPPING TRAY DIMENSIONS (2 UNITS PER TRAY)

CORRUGATED BOX

FOAM TRAYS (3)

PAD, 1/2" THK (1)

MATERIAL: DOW 220 ANTISTAT ETHAFOAM

(DENSITY: 34-35 Kg/m3)

0.25 (6.4)

9.92

(252.0)

9.92

(252.0)

45°

6.85

(174.0)

1.54 (39.0)

0.46

(11.6)

0.46

(11.6)

4.38

(111.3)

4.38

(111.3)

4x R 0.50 (12.7) 4x

2.19

(55.6)

2.19

(55.6)

ASECTION A-A

SCALE 1 : 1

1.25

(31.8)

0.787

(20.0)

ADHESIVE NOT PERMITTED

ON INSIDE OF CAVITY

ADHESIVE NOT PERMITTED

ON INSIDE OF CAVITY

UCR100 Series

3U High Reliability DC-DC Converters

MDC_UCR100.C02 Page 14 of 20

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Phenomenon Standard Level Coupling mode ➀Value applied Waveform Source

impedance Test procedure In operation Perf. crit. ➁

Supply related

surge

RIA 12 B +i/– i 1.5 x Vbatt 0.1/1/0.1 s 0.2  1 positive surge yes A

EN 50155 1.4 x Vbatt 1 

Direct transients

RIA 12 EN 50155:

1995

D ➃

–i/c, +i/–i 1800 Vp5/50 s 5 

5 pos. and 5

neg. impulses yes A

G ➄8400 Vp0.05/0.1 s

100 

Indirect coupled

transients

H–o/c, +o/–o, –o/–i 1800 Vp 5/50 s

L 8400 Vp 0.05/0.1 s

Electrostatic

discharge

(to case)

IEC/EN 61000-4-2 4 ➅

contact discharge 8000 Vp

1/50 ns 330 

10 positive and

10 negative

discharges

yes B

air discharge 15000 Vp

Electromagnetic

ﬁ eld

IEC/EN 61000-4-3 x ➆antenna 20 V/m AM 80% 1 kHz n.a. 80 – 1000 MHz yes A

ENV 50204 4 ➉antenna 30 V/m

50% duty

cycle, 200

Hz repetition

frequency

n.a. 900 ±5 MHz yes A

Electrical fast

transients/burst IEC/EN 61000-4-4 4 ➇

capacitive, o/c 2000 Vpbursts of 5/50

ns 5 kHz over

15 ms; burst

period: 300 ms

50 

60 s positive

60 s negative

transients per

coupling mode

yes B

direct, +i/c, –i/c,+i/–i 4000 Vp

Surges IEC/EN 61000-4-5

3 ➂i/c 2000 Vp ➂

1.2/50 s

12  5 pos. and 5

neg. surges per

coupling mode

yes B

2 ➂+i/–i 1000 Vp ➂2 

Conducted

disturbances IEC/EN 61000-4-6 3 ➈ i, o, signal wires 10 VAC (140 dBV) AM 80% 1 kHz 150  0.15 – 80 MHz yes A

Electromagnetic Compatibility (EMC) Immunity:

A transorb diode together with a symmetrical input ﬁ lter form an effective protection against high input transient voltages, which typically occur in most installations,

but especially in battery-driven mobile applications. The UCR-Series are tested to the following speciﬁ cations:

➀ i = input, o = output, c = case.

➁ A = Normal operation, no deviation from specs, B = Temporary deviation from specs possible.

➂ Measured with an external input capacitor speciﬁ ed in table 4 of the standard.

➃ Corresponds to EN 50155:2001, waveform A, and EN 50121-3-2:2000, table 7.2.

➄ Corresponds to EN 50155:2001, waveform B.

➅Corresponds to EN 50121-3-2:2000, table 9.2.

➆ Corresponds to EN 50121-3-2:2000, table 9.1.

➇ Corresponds to EN 50121-3-2:2000, table 7.1.

➈ Corresponds to EN 50121-3-2:2000, table 7.4.

➉ Fulﬁ lls also EN 50121-5:2000, table 1.2, where ENV 50204 is referenced.

UCR100 Series

3U High Reliability DC-DC Converters

MDC_UCR100.C02 Page 15 of 20

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Immunity to Environmental Conditions

Test method Standard Test Conditions Status

Cab Damp heat steady state IEC/EN 60068-2-78

MIL-STD-810D section 507.2

Temperature: 40 ±2 °C

Relative humidity: 93 +2/-3 %

Duration: 56 days

Converter not operating

Kb Salt mist, cyclic (sodium

chloride NaCl solution) IEC/EN 60068-2-52

Concentration: 5% (30°C) for 2 hours

Storage: 40°C, 93% rel. humidity for 22 hours

Number of cycles 3 (= 3 days)

Converter not operating

Eb Bump (half-sinusoidal) IEC/EN 60068-2-29

MIL-STD-810D section 516.3

Acceleration amplitude: 25 gn = 245 m/s2

Bump duration: 11 ms

Number of bumps: 6000 (1000 in each direction)

Converter operating

Fc Vibration (sinusoidal) IEC/EN 60068-2-6

MIL-STD-810D section 514.3

Acceleration amplitude: 0.35 mm (10 – 60 Hz)

5 gn = 49 m/s2 (60 - 2000 Hz)

Frequency (1 Oct/min): 10 – 2000 Hz

Test duration: 7.5 hours (2.5 hours in each axis)

Converter operating

Ea Shock (half-sinusoidal) IEC/EN 60068-2-27

MIL-STD-810D section 516.3

Acceleration amplitude: 50 gn = 490 m/s2

Bump duration: 11 ms

Number of bumps: 18 (3 in each direction)

Converter operating

-- Shock EN 50155 / EN 61373 sect. 10,

class A and B body mounted ➀

Acceleration amplitude: 5.1 gn

Bump duration: 30 ms

Number of bumps: 18 (3 in each direction)

Converter operating

Fda Random vibration wide

band Reproducibility high

IEC/EN 60068-2-35

DIN 40046 part 23

Acceleration spectral density: 0.05 gn2/Hz

Frequency band: 20 – 500 Hz

Acceleration magnitude: 4.9 gn rms

Test duration: 3 hours (1 hour in each axis)

Converter operating

Simulated long life testing

at increased random vibra-

tion levels

EN 50155 / EN 61373 sect. 9,

cat 1, class B, body mounted ➀

Acceleration spectral density: 0.02 gn2/Hz

Frequency band: 5 – 150 Hz

Acceleration magnitude: 0.8 gn rms

Test duration: 15 hours (5 hours in each axis)

Converter operating

➀ Body mounted = chassis of a railway coach

Technical Notes

Start-Up Threshold and Undervoltage Shutdown

Under normal start-up conditions, the UCR Series will not begin to regulate

properly until the ramping input voltage exceeds the Start-Up Threshold.

Once operating, devices will turn off when the applied voltage drops below

the Undervoltage Shutdown point. Devices will remain off as long as the

undervoltage condition continues. Units will automatically re-start when the

applied voltage is brought back above the Start-Up Threshold. The hysteresis

built into this function avoids an indeterminate on/off condition at a single input

voltage. See Performance/Functional Speciﬁ cations table for actual limits.

Start-Up Time

The VIN to VOUT Start-Up Time is the interval between the point at which a

ramping input voltage crosses the Start-Up Threshold voltage and the point at

which the fully loaded output voltage enters and remains within its speciﬁ ed

1% accuracy band. Actual measured times will vary with input source imped-

ance, external input capacitance, and the slew rate and ﬁ nal value of the input

voltage as it appears to the converter. The On/Off to VOUT start-up time assumes

that the converter is turned off via the Remote On/Off Control with the nominal

input voltage already applied.

On/Off Control

The primary-side, Remote On/Off Control function is off when On/Off is high/

open and on when On/Off is pulled low or grounded. See Figure 4.

Dynamic control of the remote on/off function is best accomplished with a

mechanical relay or an open-collector/open-drain drive circuit (optically iso-

lated if appropriate). The drive circuit should be able to sink appropriate current

(see Performance Speciﬁ cations) when activated and withstand appropriate

voltage when deactivated.

Current Limiting

When power demands from the output falls within the current limit inception

range for the rated output current, the DC-DC converter will go into a current

limiting mode. In this condition the output voltage will decrease proportionately

with increases in output current, thereby maintaining a somewhat constant

power dissipation. This is commonly referred to as power limiting. Current

limit inception is deﬁ ned as the point where the full-power output voltage

falls below the speciﬁ ed tolerance. If the load current being drawn from the

converter is signiﬁ cant enough, the unit will go into a short circuit condition.

See “Short Circuit Condition.”

UCR100 Series

3U High Reliability DC-DC Converters

MDC_UCR100.C02 Page 16 of 20

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Output Overvoltage Protection

The output voltage is monitored for an overvoltage condition via magnetic

coupling to the primary side. If the output voltage rises to a fault condition,

which could be damaging to the load circuitry (see Functional Speciﬁ cations),

the sensing circuitry will power down the PWM controller causing the output

voltage to decrease. Following a time-out period the PWM will restart, causing

the output voltage to ramp to its appropriate value. If the fault condition per-

sists, and the output voltages again climb to excessive levels, the overvoltage

circuitry will initiate another shutdown cycle. This on/off cycling is referred to

as "hiccup" mode.

Input Fusing

Certain applications and/or safety agencies may require the installation of

fuses at the inputs of power conversion components. Fuses should also be

used if the possibility of a sustained, non-current-limited, input-voltage polarity

reversal exists. For MPS UCR Series DC-DC Converters, fast-blow fuses are

recommended with values no greater than twice the maximum input current.

Trimming Output Voltage

UCR converters have a trim capability that enables users to adjust the output

voltage from -10% to +10% of Vnominal. Adjustments to the output voltage

can be accomplished with a single ﬁ xed resistor as shown in Figures 5 and 6.

A single ﬁ xed resistor can increase or decrease the output voltage depending

on its connection. Resistors should be located close to the converter and have

TCR's less than 100ppm/°C to minimize sensitivity to changes in temperature. If

the trim function is not used, leave the trim pin open.

Trim adjustments greater than the speciﬁ ed -10% to +10% can have an

adverse affect on the converter’s performance and are not recommended.

Excessive voltage differences between VOUT and Sense, in conjunction with trim

adjustment of the output voltage, can cause the overvoltage protection circuitry

to activate (see Functional Speciﬁ cations for overvoltage limits).

Use only one trim up or trim down resistor. Do not connect both resistors

simultaneously. When trimming, do not exceed maximum output power.

30 +Vcc

REF

+ Vin

CONTROL

–Vin

ON/OFF

COMMON

Figure 4. Driving the Remote On/Off Control Pin

Short Circuit Condition

When a converter is in current limit mode the output voltages will drop as

the output current demand increases. If the output voltage drops too low, the

magnetically coupled voltage used to develop primary side voltages will also

drop, thereby shutting down the PWM controller. Following a time-out period,

the PWM will restart, causing the output voltages to begin ramping to their

appropriate values. If the short-circuit condition persists, another shutdown

cycle will be initiated. This on/off cycling is referred to as “hiccup” mode. The

hiccup cycling reduces the average output current, thereby preventing internal

temperatures from rising to excessive levels. The UCR is capable of enduring

an indeﬁ nite short circuit output condition.

Thermal Shutdown

UCR converters are equipped with thermal-shutdown circuitry. If the inter-

nal temperature of the DC-DC converter rises above the designed operating

temperature (See Performance Speciﬁ cations), a precision temperature sensor

will power down the unit. When the internal temperature decreases below the

threshold of the temperature sensor, the unit will self start.

LOAD

RTRIM UP

+Vout

+Vin

–Vin

ON/OFF TRIM

+SENSE

–Vout

–SENSE

Figure 5. Trim Connections to Increase Output Voltage Using Fixed Resistors

RTRIM Up (k) = ___________________

2.5V x (Vout ÷ Vnom - 1)

4 x (Vout – 2.5V)

LOAD

TRIM DOWN

+Vout

+Vin

–Vin

ON/OFF TRIM

+SENSE

–Vout

–SENSE

Figure 6. Trim Connections to Decrease Output Voltage Using Fixed Resistors

RTRIM Down (k) = __________

Vnom - Vout

4 x Vout

Fuse Specifications

Model Fuse Type Reference and rating

UCR100-050-T72-C Fast-blow 15A 250V

UCR100-120-T72-C Fast-blow 18A 250V

UCR100-240-T72-C Fast-blow 20A 250V

UCR100 Series

3U High Reliability DC-DC Converters

MDC_UCR100.C02 Page 17 of 20

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Remote Sense

UCR series converters employ a sense feature to provide point of use regula-

tion, thereby overcoming moderate IR drops in pcb conductors or cabling.

The remote sense lines carry very little current and therefore require minimal

cross-sectional-area conductors. The sense lines, which are capacitively

coupled to their respective output lines, are used by the feedback control-loop

to regulate the output. As such, they are not low impedance points and must

be treated with care in layouts and cabling. Sense lines on a pcb should be run

adjacent to dc signals, preferably ground. In cables and discrete wiring applica-

tions, twisted pair or other techniques should be implemented.

UCR series converters will compensate for drops between the output voltage

at the DC-DC converter output pins and the voltage at the DC-DC sense input

pins provided that:

[VOUT(+) – VOUT(–)] – [Sense(+) – Sense (–)]  10% VOUT

Output overvoltage protection is monitored at the output voltage pin, not

the Sense pin. Therefore, excessive voltage differences between VOUT and

Sense in conjunction with trim adjustment of the output voltage can cause the

overvoltage protection circuitry to activate (see Performance Speciﬁ cations

for overvoltage limits). Power derating is based on maximum output current

and voltage at the converter’s output pins. Use of trim and sense functions can

cause output voltages to increase, thereby increasing output power beyond the

conveter’s speciﬁ ed rating, or cause output voltages to climb into the output

overvoltage region. Therefore, the designer must ensure:

(VOUT at pins)  (IOUT)  rated output power

Note: The Sense and VOUT lines are internally connected through low-value

resistors. Nevertheless, if the sense function is not used for remote regulation

the user must connect the +Sense to +VOUT and -Sense to –VOUT at the DC-DC

converter pins.

LOAD

+Vout

–Vin

Sense Current

Contact and PCB resistance

losses due to IR drops

Contact and PCB resistance

losses due to IR drops

Sense Return

+Vin

ON/OFF TRIM

+SENSE

–Vout

–SENSE

IOUT Return

IOUT

Figure 7. Remote Sense Circuit Conﬁ guration

Features and Options

Hold-Up Time

The hold-up time function provided by the UCR100 is designed to work with

an external hold-up capacitor that is charged from circuitry internal to the

converter. Hold-up time is deﬁ ned as the duration of time that the DC-DC

converter output will remain active following a loss of input power. When the

hold-up function is activated, the UCR100 uses the hold-up capacitor energy to

support operation. This provides a charge that maintains the DC-DC converter

in operation for 10ms of hold-up time. The capacitors in the application are

recommended below. The values in the table are standard capacitor values that

will provide a hold-up time of better than 10ms.

Figure 8 shows the relationship between the input voltage and the fall of the

output voltage.

Converter Input

Source Voltage

Converter

Output Voltage

Hold-Up Time

Vout nom

Vout min

Figure 8. Hold-up Time to DC-DC Converter

Vin 24V 36V 48V 72V 96V 110V

Standard 1900µf 1000µf 860µf 680µf 510µf 1200µf

Working Voltage 75VDC 100VDC 100VDC 150VDC 150VDC 150VDC

Conformal Coating

The UCR modules have conformal coating to protect them against moisture,

dust, and chemical and temperature extremes during all types of applications.

They provide environmental and mechanical protection to extend the life of the

components and circuitry signiﬁ cantly. Conformal coating on the UCR modules

is applied by dipping. Conformal coating protects the UCR modules from mois-

ture and contaminants, preventing short circuits and corrosion of conductors

and solder joints. In addition, the use of conformal coating protects circuits and

components from abrasion and solvents. Stress relief is also provided, as well

as protection of the insulation resistance of the module. The conformal coating

is particularly useful for protecting circuitry in severe service environments,

while maintaining a low stress environment for components and connections.

UCR100 Series

3U High Reliability DC-DC Converters

MDC_UCR100.C02 Page 18 of 20

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Figure 9. Connection of External Hold-up Capacitor

UCR100

+Vout

–Vin

H-UP

+Vin

–Vout

Figure 9 shows the connection of the external output capacitor for the UCR100

model.

Undervoltage Lockout

URC series converters with the –V or –SV sufﬁ x have an undervoltage lockout

feature that will shut down the controller if the input voltage falls below an

adjustable threshold. The undervoltage threshold is determined by the value

of a resistor placed between the UVLO and –Vin. Figure 10 shows a typical

conﬁ guration.

The converter will remain off as long as the input voltage remains below the

UVLO threshold. Devices will automatically restart when the applied volt-

age rises above the UVLO threshold. The hysteresis built into this function

prevents an indeterminate on/off condition at a single input voltage. The table

below shows common UVLO values for various nominal input voltages and the

required resistor value for each.

Vin Nominal (V) 24 36 48 72 96 110

UVLO (V) 14.4 (±1V) 21.6 (±1V) 28.8 (±1V) 43.2 (±1V) 57.6 (±1V) 66 (±1V)

UVLO External

Trim Resistor

(KΩ)

50 11.5 6.1 2.7 1.5 1.1

Using Multiple Converters

UCR converters may be connected in series to achieve a higher output voltage.

URC converters with the optional current share feature (-S and -SV models)

may also be connected in parallel to support higher output current, to improve

redundancy or to spread the thermal load in high power, high temperature

environments. Please refer to the typical circuits below. For all modes, use

short connections with sufﬁ cient wire gauge and adequate grounding. Trim

circuits are not shown in the following diagrams however they are the same as

the Output Adjustment section.

A desirable feature of using multiple converters is that, since all units are

isolated, they can use a common input power supply. Or you may use separate

inputs for redundancy.

When using units with the load share option in stand-alone operation

with the remote sense feature, the load share pin must be connected to

-Vout. This connection is not needed if the remote sense lines are con-

nected directly at the connector.

Using series connections (see ﬁ gure 11)

Figure 11 illustrates a typical conﬁ guration for two URC converters connected

in series. The Current Share inputs should be left ﬂ oating or tied to -Vout.

When connected in series the maximum load regulation remains constant as a

percentage of the series output voltage. The total percentage of regulation does

not change over the series string however the regulation amounts (in millivolts)

accumulate in each converter.

When trimming UCRs in a series-connected chain, be sure to avoid exceed-

ing the voltage trim limits for each individual converter. Speciﬁ cally, try to make

the trim adjustments approximately equal on all series-connected converters.

Using parallel connections – Load Sharing (see ﬁ gure 12)

The +Sense must be left open when current sharing is required. Be sure to

differentiate between wiring for redundancy or wiring for load sharing which

is greater than one converter’s output current rating. Redundant connections

RLOAD

+Vout

–Vin

+Vin

UCR #1

UCR #2

Current Share Floating

or -Vout

+SENSE

–Vout

–SENSE

Floating

or -Vout

+Vout

–Vin

+Vin

Current Share

COMMON

Vin

SUPPLY

+SENSE

–Vout

–SENSE

Figure 11. Series Connections

Figure 10. Undervoltage Lockout Conﬁ guration

UCR100

+Vout

–Vin

K

UVLO

+Vin

–Vout

UCR100 Series

3U High Reliability DC-DC Converters

MDC_UCR100.C02 Page 19 of 20

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Figure 12. Load-Sharing Parallel Connections

RLOAD

+Vout

–Vin

+Vin

UCR #1

UCR #2

Current Share

Floating

+SENSE

–Vout

–SENSE

+Vout

–Vin

+Vin

Current Share

Additional UCRs

Vin

SUPPLY

+SENSE

–Vout

–SENSE

Figure 13. Redundant Parallel Connections

RLOAD

+Vout

–Vin

+Vin

UCR #1

UCR #2

Current Share

“OR’ing” diode

+SENSE

–Vout

–SENSE

+Vout

–Vin

+Vin

Current Share

Vin

SUPPLY

+SENSE

–Vout

–SENSE

Floating

Figure 14. Optional Redundant Parallel Sense Wiring

RLOAD

+Vout

–Vin

+Vin

UCR #1

UCR #2

Current Share

+SENSE

–Vout

–SENSE

+Vout

–Vin

+Vin

Current Share

COMMON

Vin

SUPPLY

+SENSE

–Vout

–SENSE

expect one or the remaining converters to absorb the whole load if one con-

verter fails. Therefore the entire load cannot exceed the rating of one converter.

Load sharing requires all parallel converters to be operational since failure

of one converter forces all others to go into overcurrent shutdown. For two or

more parallel load sharing converters, connect all Current Share pins together.

The load-share parallel current circuit requires interconnection of the Current

Share pins between each converter to insure that the current load is approxi-

mately balanced between all converters.

Using parallel connections – Redundancy

The redundancy connections in ﬁ gures 13 and 14 requires external user-

supplied “OR’ing” diodes to share the load. The diodes prevent one converter

with slightly higher voltage forcing current into the lower-current converter. The

diodes also protect the application against catastrophic “crow-barring” failure

(shorted output) by one of the converters.

The diodes should be identical part numbers to enhance balance between

the two converters. The default factory nominal voltage should be sufﬁ ciently

matched between converters however you may wish to add optional external

trim circuits to make the load approximately equal. Adjust the converters for

equal output voltage before connecting in parallel.

The OR’ing diode system is the responsibility of the user. Be aware of the

power levels applied to the diodes and possible heat sink requirements.

Be very careful placing the diodes “in the loop” when when using Sense

inputs. This might cause the output terminals to exceed their +10% trim range

or maximum power outputs. Schottky power diodes with approximately 0.3 Volt

drops may be suitable in the loop whereas 0.7 Volt silicon power diodes may

not be advisable. The Sense inputs are being asked to compensate for both

the diode drop and the wiring losses. Placing the diodes “in the loop” provides

better system regulation at the risk of exceeding power levels (see ﬁ gure 14).

UCR100 Series

3U High Reliability DC-DC Converters

MDC_UCR100.C02 Page 20 of 20

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