UCE-5/20-D48PBH-Y - Murata Power Solutions

UCE Series

Isolated, High-Density, Eighth-Brick

Low Proﬁ le DC-DC Converters

MDC_UCE.C02 Page 1 of 17

www.murata-ps.com

www.murata-ps.com/support

For full details go to

www.murata-ps.com/rohs

Figure 1. Simpliﬁ ed Block Diagram

FEATURES

 Industry standard eighth-brick pinout

and package

 Low proﬁ le 0.4" height with 0.9" x 2.3"

outline dimensions

 36 to 75 Vdc input range (48V nominal)

 Fully isolated, 2250 Vdc (BASIC)

insulation

 Outstanding thermal performance

and derating

 Extensive self-protection and short

circuit features with no output reverse

conduction

 On/Off control, trim and sense functions

 Interleaved synchronous rectiﬁ cation

yields high efﬁ ciency over 90%

 Fully protected against temperature and

voltage limits

 RoHS-6 or RoHS-5 compliant

 Certiﬁ ed to UL/EN/IEC 60950-1 and

CAN/CSA C22.2 No. 60950-1, 2nd Edition

safety approvals

Units are offered with ﬁ xed output voltages from

1.5 to 12 Volts and currents up to 30 Amps. UCEs

operate over a wide temperature range (up to +85

degrees Celsius at moderate airﬂ ow) with full rated

power. Interleaved synchronous rectiﬁ er topology

yields excellent efﬁ ciency over 90% and no reverse

output conduction.

UCEs achieve these impressive mechanical and

environmental specs while delivering excellent

electrical performance in a through-hole package.

Overall noise is typically 50 mV pk-pk (low voltage

models) with fast step response. These converters

offer tight output regulation and high stability even

with no load. The unit is fully protected against

input undervoltage, output overcurrent and short

circuit. An on-board temperature sensor shuts

down the converter if thermal limits are reached.

“Hiccup” output protection automatically restarts

the converter when the fault is removed.

A convenient remote On/Off control input enables

phased startup and shutdown in multi-voltage ap-

plications. To compensate for longer wiring and to

retain output voltage accuracy at the load, UCEs em-

ploy a Sense input to dynamically correct for ohmic

losses. A trim input may be connected to a user’s

adjustment potentiometer or trim resistors for output

voltage calibration. The UCE will tolerate substantial

capacitive loading for bypass-cap applications.

UCEs include industry-standard safety certiﬁ ca-

tions and BASIC I/O insulation provides input/output

isolation to 2250V. Radiation emission testing is

performed to widely-accepted EMC standards.

PRODUCT OVERVIEW

Typical unit

Typical topology is shown.

For efﬁ cient, fully isolated DC power in the smallest space, the UCE

open frame DC-DC converter series ﬁ t in industry-standard “eighth

brick” outline dimensions and mounting pins (on quarter-brick pinout).

+VIN

(2)

(8)

(1)

(3)

(7)

–VIN

OPTO

ISOLATION

REFERENCE &

ERROR AMP

PULSE

TRANSFORMER

INPUT UNDERVOLTAGE, INPUT

OVERVOLTAGE, AND OUTPUT

OVERVOLTAGE COMPARATORS

REMOTE

ON/OFF

CONTROL

+VOUT

(4)

−VOUT

(6)

VOUT TRIM

+SENSE

(5)

−SENSE

SWITCH

CONTROL

PWM

CONTROLLER

SIMPLIFIED BLOCK DIAGRAM

UCE Series

Isolated, High-Density, Eighth-Brick

Low Proﬁ le DC-DC Converters

MDC_UCE.C02 Page 2 of 17

www.murata-ps.com/support

PART NUMBER STRUCTURE

Maximum Rated Output

Current in Amps

Eighth-Brick Package

Output Conﬁ guration:

U = Unipolar/Single

Nominal Output Voltage

U CE -/D48-3.3 30 N B

Input Voltage Range:

D48 = 36-75V,

48V nominal

PERFORMANCE SPECIFICATIONS SUMMARY AND ORDERING GUIDE

Model Family

Output Input

Efﬁ ciency  Package

VOUT

(V)

IOUT

(A)

Power

(W)

Ripple & Noise

(mVp-p) Regulation (max.) VIN Nom.

(V)

Range

(V)

IIN, no

load

(mA)

IIN, full

load

(A)Typ. Max. Line Load Min. Typ. Case Pinout

UCE-1.2/25-D48 1.2 25 30 Please contact Murata Power Solutions for further information.

UCE-1.5/20-D48 1.5 20 30 50 100 ±0.15% ±0.3% 48 36-75 50 0.72 85% 87% C56 P32

UCE-1.5/40-D48 1.5 40 60 Please contact Murata Power Solutions for further information.

UCE-1.8/30-D48 1.8 30 54 30 80 ±0.125% ±0.25%

48 36-75

45 1.28 87% 88%

C56 P32

UCE-2.5/20-D48 2.5 20 50

50 1.14 88% 91%

UCE-3.3/15-D48 3.3 15 49.5

100 60 1.15 86% 90%

UCE-3.3/30-D48 3.3 30 99 ±0.1% ±0.2% 2.27 89% 91%

UCE-5/10-D48 51050

±0.125% ±0.25%

30 1.15 88% 90.5%

UCE-5/20-D48 5 20 100 30 60

2.25 90% 92.5%

UCE-12/4.2-D48 12 4.2 50.4 150

300

1.14

86%

92%

UCE-12/8.3-D48 12 8.3 99.6 200 2.31 90%

UCE-12/10-D48 12 10 120 2.78

 Please refer to the model number structure for additional ordering part numbers and options.

Conformal coating (optional)

Blank = no coating, standard

H = Coating added, optional, special quantity order

RoHS Hazardous Materials compliance

C = RoHS6 (does not claim EU RoHS exemption 7b–lead in solder), standard

Y = RoHS5 (with lead), optional, special quantity order

Note: Some model combinations may not be

available. Contact Murata Power Solutions for

availability.

On/Off Control Logic

N = Negative logic, standard

P = Positive logic, optional

Baseplate (optional, not available on some models)

Blank = No baseplate, standard

B = Baseplate installed, optional, special quantity order

(Through-hole packages only)

Blank = Standard pin length 0.180 inches (4.6mm)

L1 = Pin length 0.110 inches (2.79mm)*

L2 = Pin length 0.145 inches (3.68mm)*

Pin Length Option

Product Adaptations

Murata Power Solutions offers several variations of our core product family.

These products are available under scheduled quantity orders and may also

include separate manufacturing documentation from a mutually agreeable

Product Speciﬁ cation. Since these product adaptations largely share a common

parts list and similar speciﬁ cations and test methods with their root products,

they are provided at excellent costs and delivery. Please contact Murata Power

Solutions for details.

As of this date, the following products are available:

UCE-3.3/30-D48NHL2-Y

UCE-12/4.2-D48NHL2-Y

These models are all negative On/Off logic, no baseplate, conformal coating

added, 3.68mm pin length, and RoHS-5 hazardous substance compliance (with

lead).

*Special quantity order is required;

no sample quantities available.

UCE Series

Isolated, High-Density, Eighth-Brick

Low Proﬁ le DC-DC Converters

MDC_UCE.C02 Page 3 of 17

www.murata-ps.com/support

INPUT CHARACTERISTICS

Model Family

Start-up

threshold

Min.

(A)

Under-

voltage

Shut-

down

(V)

Reflected

(back)

Ripple

Current

(mA)②

Internal

Input Filter

Type

Reverse

Polarity

Protection

Remote On/Off Control

Inrush

Transient

A2sec

Output

Short

Circuit

(mA)

Low Line

(VIN=min.)

(A)

Standby

Mode

(mA)

Current

(mA)

Positive Logic

“P” Model

Suffix

Negative Logic

“N” Model

Suffix

UCE-1.5/20-D48

10-30,

model

dependent

0.05

A2sec

50-150,

model

dependent

0.97

1-10,

model

dependent

L-C

None, install

external fuse 1.0

OFF=Ground

pin to +1V max.

ON=open or

+3.5 to +15V

max.

OFF=open or

+2.5V to

+15V max.

ON=Ground pin to

+0.8V max.

UCE-1.8/30-D48 32.5 1.72

UCE-2.5/20-D48 32 1.53

UCE-3.3/15-D48 32 1.54

UCE-3.3/30-D48 32 3.06

UCE-5/10-D48 34.5 32 1.53 Pi

UCE-5/20-D48 34 31.5 3.00 Pi

UCE-12/4.2-D48

34 32

1.52

L-C

UCE-12/8.3-D48 3.07

UCE-12/10-D48 500 3.70

OUTPUT CHARACTERISTICS

Model Family

VOUT

Accuracy

50% Load

% of VNOM

Capacitive

Loading Max. Low

ESR <0.02Ω Max.

μF

Adjustment

Range

Temperature

Coefﬁ cient

Minimum

Remote

Sense

Compen-

sation

Ripple/

Noise

(20 MHz

bandwidth)

Line/Load

Regulation Efﬁ ciency

Current Limit

Inception

98% of Vout,

after warmup

UCE-1.5/20-D48

±1%

10,000

–10 to

+10% of

Vnom.

±0.02% of

Vout range

per °C

No minimum

load +10% See ordering guide

24.5

UCE-1.8/30-D48 36

UCE-2.5/20-D48 32

UCE-3.3/15-D48 24

UCE-3.3/30-D48 35

UCE-5/10-D48 1000 15.

UCE-5/20-D48 10,000 23 min.

UCE-12/4.2-D48

1000

5.5

UCE-12/8.3-D48 12

UCE-12/10-D48 13

ISOLATION CHARACTERISTICS

Model Family

Input to Output

Min.

Input to

baseplate

Min.

Baseplate to output

Min.

Isolation

Resistance

MΩ

Isolation

Capacitance

pF Isolation Safety Rating

UCE-1.5/20-D48

2250 1500 1500

100

1000 Basic Insulation

UCE-1.8/30-D48 10

UCE-2.5/20-D48

100

UCE-3.3/15-D48

UCE-3.3/30-D48

UCE-5/10-D48

UCE-5/20-D48

UCE-12/4.2-D48

UCE-12/8.3-D48

UCE-12/10-D48

FUNCTIONAL SPECIFICATIONS

UCE Series

Isolated, High-Density, Eighth-Brick

Low Proﬁ le DC-DC Converters

MDC_UCE.C02 Page 4 of 17

www.murata-ps.com/support

Input Voltage:

Continuous:

48 Volt input models 75 Volts

Transient (100 mSec. Max.)

48 Volt input models 100 Volts

On/Off Control +15 Volts

Input Reverse Polarity Protection None, install external fuse.

Output Overvoltage Protection Magnetic feedback.

See speciﬁ cations.

Output Current Current-limited. Devices can

withstand sustained short circuit

without damage.

Storage Temperature –40 to +125°C.

Lead Temperature See soldering guidelines.

Absolute maximums are stress ratings. Exposure of devices to greater than any of these

conditions may adversely affect long-term reliability. Proper operation under conditions

other than those listed in the Performance/Functional Speciﬁ cations Table is not implied

or recommended.

ABSOLUTE MAXIMUM RATINGS

DYNAMIC CHARACTERISTICS

Model Family

Dynamic Load

Response

(50-75-50%

load step) to 1%

of ﬁ nal value,

μSec

(See note 1)

Start-up Time

Switching

Frequency

KHz

VIN to VOUT

regulated

(Max.)

Remote On/

Off to VOUT

regulated

(Max.)

mSec

UCE-1.5/20-D48 100 50 50 480

UCE-1.8/30-D48 150 10 10 400

UCE-2.5/20-D48 100 50 50 350

UCE-3.3/15-D48 200 50 50 480

UCE-3.3/30-D48 50 15 10 380

UCE-5/10-D48 100 50 50 400

UCE-5/20-D48 100 max. 10 10 330

UCE-12/4.2-D48 30 60 60

200

UCE-12/8.3-D48 50 50 50

UCE-12/10-D48 50 60 60

FUNCTIONAL SPECIFICATIONS, CONTINUED

MISCELLANEOUS CHARACTERISTICS

Model Family

Calculated

MTBF4

Operating

Temperature Range

with derating

(°C)

Operating

PCB

Temperature

(no derating)

Storage

Temperature

Range

(°C)

Thermal

Protection/

Shutdown

(ºC)

Short

Circuit

Current

(A)

Overvoltage

Protection12

(V) Via

magnetic

feedback

(V)

Short Circuit

Protection

Method

Short Circuit

Duration16

Relative

Humidity

(non-condensing)

UCE-1.5/20-D48 TBC

−40 to +85

−40 to +110

(model

dependent)

−55 to

+125

120 5

1.95

Current

limiting,

hiccup

autorestart.

Remove

overload for

recovery.

Continuous,

output

shorted

ground.

No dam-

age.

to +85°C/85%

UCE-1.8/30-D48 2.8 V. max

UCE-2.5/20-D48 1.8 M HRS 3

UCE-3.3/15-D48 2.4 M HRS 4.25

UCE-3.3/30-D48

UCE-5/10-D48 2.6 M HRS 110 0.5 7 max.

UCE-5/20-D48 2.7 M HRS

UCE-12/4.2-D48 TBC

125 5 14.5

UCE-12/8.3-D48 2.4 M HRS

UCE-12/10-D48

UCE Series

Isolated, High-Density, Eighth-Brick

Low Proﬁ le DC-DC Converters

MDC_UCE.C02 Page 5 of 17

www.murata-ps.com/support

PHYSICAL CHARACTERISTICS

Outline dimensions See mechanical specs (below)

Pin material Copper alloy

Pin diameter 0.04/0.062" (1.016/1.524mm)

Pin ﬁ nish Nickel underplate with gold overplate

Weight

UCE-1.5/20-D48 0.67 ounces (19 grams)

UCE-1.8/30-D48,

0.71 ounces (20 grams)

UCE-2.5/20-D48

UCE-5/10-D48

UCE-5/20-D48

UCE-12/4.2-D48

UCE-3.3/15-D48 1 ounce (28 grams)

UCE-3.3/30-D48, UCE-12/8.3-D48, UCE-12/10-D48 0.81 ounces (23 grams)

Electromagnetic interference (external ﬁ lter required) Meets EN55022/CISPR22 (requires external ﬁ lter)

Safety Certiﬁ ed to UL/cUL 60950-1, CSA-C22.2 No. 60950-1, IEC/EN 60950-1, 2nd Edition

FUNCTIONAL SPECIFICATIONS, CONTINUED

Murata Power Solutions recommends the speciﬁ cations below when installing these converters. These speciﬁ cations vary depending on the solder type. Exceed-

ing these speciﬁ cations may cause damage to the product. Your production environment may differ; therefore please thoroughly review these guidelines with

your process engineers.

Wave Solder Operations for through-hole mounted products (THMT)

For Sn/Ag/Cu based solders:

Maximum Preheat Temperature 115ºC.

Maximum Pot Temperature 270ºC.

Maximum Solder Dwell Time 7 seconds

For Sn/Pb based solders:

Maximum Preheat Temperature 105ºC.

Maximum Pot Temperature 250ºC.

Maximum Solder Dwell Time 6 seconds

SOLDERING GUIDELINES

(1) All models are tested and speciﬁ ed with external 1||10 μF ceramic/tantalum output capaci-

tors and no external input capacitor. All capacitors are low ESR types. These capacitors are

necessary to accommodate our test equipment and may not be required to achieve speciﬁ ed

performance in your applications. All models are stable and regulate within spec under no-load

conditions.

General conditions for Speciﬁ cations are +25 deg.C, VIN = nominal, VOUT = nominal, full load.

Adequate airﬂ ow must be supplied for extended testing under power.

(2) Input Ripple Current is tested and speciﬁ ed over a 5 Hz to 20 MHz bandwidth. Input ﬁ ltering

is CIN = 33 μF, 100V tantalum, CBUS = 220 μF, 100V electrolytic, LBUS = 12 μH.

(3) Note that Maximum Power Derating curves indicate an average current at nominal input

voltage. At higher temperatures and/or lower airﬂ ow, the DC-DC converter will tolerate brief

full current outputs if the total RMS current over time does not exceed the Derating curve. All

Derating curves are presented at sea level altitude. Be aware of reduced power dissipation

with increasing density altitude.

(4) Mean Time Before Failure is calculated using the Telcordia (Belcore) SR-332 Method 1, Case

3, ground ﬁ xed conditions, Tpcboard=+25 deg.C, full output load, natural air convection.

(5) The On/Off Control is normally controlled by a switch. But it may also be driven with exter-

nal logic or by applying appropriate external voltages which are referenced to Input Common.

The On/Off Control Input should use either an open collector or open drain transistor.

(6) Short circuit shutdown begins when the output voltage degrades approximately 2% from

the selected setting.

(7) The outputs are not intended to sink appreciable reverse current. This may damage the

outputs.

(8) Output noise may be further reduced by adding an external ﬁ lter. See I/O Filtering and Noise

Reduction.

(9) All models are fully operational and meet published speciﬁ cations, including “cold start” at

–40ºC.

(10) Regulation speciﬁ cations describe the deviation as the line input voltage or output load

current is varied from a nominal midpoint value to either extreme.

(11) Alternate pin length and/or other output voltages are available under special quantity order.

(12) Output overvoltage is non-latching. When the overvoltage fault is removed, the converter

will immediately recover.

(13) Do not exceed maximum power speciﬁ cations when adjusting the output trim.

(14) At zero output current, the output may contain low frequency components which exceed

the ripple speciﬁ cation. The output may be operated indeﬁ nitely with no load.

(15) If reverse polarity is accidentally applied to the input, a body diode will become forward bi-

ased and will conduct considerable current. To ensure reverse input protection with full output

load, always connect an external input fuse in series with the +VIN input.

PERFORMANCE SPECIFICATION NOTES

TYPICAL PERFORMANCE DATA

UCE Series

Isolated, High-Density, Eighth-Brick

Low Proﬁ le DC-DC Converters

MDC_UCE.C02 Page 6 of 17

www.murata-ps.com/support

3 5 7 9 11 13 15 17 19 21 23 25 27 29

Load Current (A)

Efﬁciency (%)

Vin = 75V

Vin = 48V

Vin = 36V

30 35 40 45 50 55 60 65 70 75 80

Ambient Temperature (ºC)

Output Current (A)

1.0 m/s (200 LFM)

2.0 m/s (400 LFM)

1.5 m/s (300 LFM)

0.5 m/s (100 LFM)

30 40 50 60 70 80

Ambient Temperature (ºC)

Output Current (A)

1.0 m/s (200 LFM)

1.5 m/s (300 LFM)

0.5 m/s (100 LFM)

Natural Convection

34567891011121314151617181920

Load Current (A)

Efﬁciency (%)

Vin = 75V

Vin = 48V

Vin = 36V

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

Output Current (A)

Ambient Temperature (ºC)

1.0 m/s (200 LFM)

2.0 m/s (400 LFM)

1.5 m/s (300 LFM)

0.5 m/s (100 LFM)

3 6 9 12 15 18

Vin = 75V

Vin = 48V

Vin = 36V

Load Current (A)

Efﬁciency (%)

UCE-1.5/20-D48 Maximum Current Temperature Derating

(Vin = 48V, no baseplate, longitudinal airﬂ ow at sea level)

UCE-1.8/30-D48 Maximum Current Temperature Derating

(Vin = 48V, no baseplate, longitudinal airﬂ ow at sea level)

UCE-2.5/20-D48 Maximum Current Temperature Derating

(Vin = 48V, with baseplate, longitudinal airﬂ ow at sea level)

UCE-1.5/20-D48 Efﬁ ciency vs Line Voltage & Load Current @ 25ºC

UCE-1.8/30-D48 Efﬁ ciency vs Line Voltage & Load Current @ 25ºC

UCE-2.5/20-D48 Efﬁ ciency vs Line Voltage & Load Current @ 25ºC

TYPICAL PERFORMANCE DATA

UCE Series

Isolated, High-Density, Eighth-Brick

Low Proﬁ le DC-DC Converters

MDC_UCE.C02 Page 7 of 17

www.murata-ps.com/support

030 35 40 45 50 55 60 65 70 75 80 85

Output Current (A)

Ambient Temperature (ºC)

1.0 m/s (200 LFM)

2.0 m/s (400 LFM)

1.5 m/s (300 LFM)

0.5 m/s (100 LFM)

3456789101112131415

Load Current (A)

Efﬁciency (%)

Vin = 75V

Vin = 48V

Vin = 36V

3 4 5 6 7 8 9 101112131415161718192021222324252627282930 0

Loss (Watts)

Load Current (A)

Efﬁciency (%)

Vin = 75V

Vin = 48V

Power Dissipation

Vin = 48V

Vin = 36V

30 40 50 60 70 80

Ambient Temperature (ºC)

Output Current (A)

1.0 m/s (200 LFM)

2.0 m/s (400 LFM)

1.5 m/s (300 LFM)

0.5 m/s (100 LFM)

Natural Convection

30 40 50 60 70 80

Ambient Temperature (ºC)

Output Current (A)

1.0 m/s (200 LFM)

2.0 m/s (400 LFM)

1.5 m/s (300 LFM)

0.5 m/s (100 LFM)

Natural Convection

UCE-3.3/15-D48 Maximum Current Temperature Derating

(Vin = 48V, no baseplate, longitudinal airﬂ ow at sea level)

UCE-3.3/30-D48 Maximum Current Temperature Derating

(Vin=48V, no baseplate, transverse airﬂ ow at sea level)

UCE-3.3/15-D48 Efﬁ ciency Vs. Line Voltage & Load Current @ +25ºC

UCE-3.3/30-D48 Efﬁ ciency vs Line Voltage & Load Current @ 25ºC

UCE-3.3/30-D48 Maximum Current Temperature Derating

(Vin=48V, no baseplate, longitudinal airﬂ ow at sea level)

TYPICAL PERFORMANCE DATA

UCE Series

Isolated, High-Density, Eighth-Brick

Low Proﬁ le DC-DC Converters

MDC_UCE.C02 Page 8 of 17

www.murata-ps.com/support

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

Natural Convection

Ambient Temperature (ºC)

Output Current (A)

1.0 m/s (200 LFM)

2.0 m/s (400 LFM)

1.5 m/s (300 LFM)

0.5 m/s (100 LFM)

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

Natural Convection

Ambient Temperature (ºC)

Output Current (A)

1.0 m/s (200 LFM)

2.0 m/s (400 LFM)

1.5 m/s (300 LFM)

0.5 m/s (100 LFM)

100

12345678910

0.5

1.5

2.5

3.5

Power Dissipation (Watts)

Load Current (A)

Efﬁciency (%)

Vin = 75V

Vin = 48V

Vin = 36V

Power Dissipation (Vin = 48V)

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

Load Current (A)

Efﬁciency (%)

Vin = 75V

Vin = 48V

Vin = 36V

Power Dissipation (Vin = 48V)

Power Dissipation (Watts)

0.6 1.2 1.8 2.4 3.0 3.6 4.2

Load Current (A)

Efﬁciency (%)

Vin = 75V

Vin = 48V

Vin = 36V

UCE-5/10-D48 Maximum Current Temperature Derating at Sea Level

(Vin = 48V, transverse airﬂ ow, no baseplate)

UCE-5/20-D48 Maximum Current Temperature Derating at Sea Level

(Vin = 48V, transverse airﬂ ow, no baseplate)

UCE-5/10-D48 Efﬁ ciency Vs. Line Voltage & Load Current @ +25ºC

UCE-5/20-D48 Efﬁ ciency Efﬁ ciency and Power Dissipation @ Ta = +25ºC

UCE-12/4.2-D48 Efﬁ ciency Vs. Line Voltage & Load Current @ +25ºCThermal image with hot spot at full load current with 25 °C ambient; air is ﬂ owing at

100 LFM. Air is ﬂ owing across the converter from V– to V+ at 48V input. Identiﬁ able

and recommended maximum value to be veriﬁ ed in application.

T5 & Q7, max temp = 120 °C / IPC9592 guidelines.

TYPICAL PERFORMANCE DATA

UCE Series

Isolated, High-Density, Eighth-Brick

Low Proﬁ le DC-DC Converters

MDC_UCE.C02 Page 9 of 17

www.murata-ps.com/support

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

Ambient Temperature (ºC)

Output Current (A)

1.0 m/s (200 LFM)

2.0 m/s (400 LFM)

1.5 m/s (300 LFM)

0.5 m/s (100 LFM)

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

Ambient Temperature (ºC)

Output Current (A)

1.0 m/s (200 LFM)

2.0 m/s (400 LFM)

1.5 m/s (300 LFM)

0.5 m/s (100 LFM)

345678

Load Current (A)

Efﬁciency (%)

Vin = 75V

Vin = 48V

Vin = 36V

UCE-12/8.3-D48 Maximum Current Temperature Derating

(Vin = 48V, no baseplate, longitudinal airﬂ ow at sea level)

UCE-12/10-D48 Maximum Current Temperature Derating at sea level

(Vin = 48V, no baseplate, airﬂ ow direction from Vin to Vout)

UCE-12/8.3-D48 Efﬁ ciency vs Line Voltage & Load Current @ 25ºC

UCE-12/8.3-D48 Maximum Current Temperature Derating at sea level

(Vin = 48V, with baseplate, airﬂ ow is from -Vin to +Vin)

UCE-12/10-D48 Efﬁ ciency and Power Dissipation @ Ta = +25ºC

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

Natural Convection

Ambient Temperature (ºC)

Output Current (A)

1.0 m/s (200 LFM)

2.0 m/s (400 LFM)

1.5 m/s (300 LFM)

0.5 m/s (100 LFM)

100

345678910

Load Current (A)

Efﬁciency (%)

Vin = 75V

Vin = 48V

Vin = 36V

Power Dissipation (Vin = 48V)

Power Dissipation (Watts)

3.25

3.5

3.75

4.25

30 40 50 60 70 80

Ambient Temperature (ºC)

Output Current (A)

0.5 m/s (100 LFM)

1.0 to 2.0 m/s (200 to 400 LFM)

UCE-12/4.2-D48 Maximum Current Temperature Derating

(Vin = 48V, no baseplate, longitudinal airﬂ ow at sea level)

UCE Series

Isolated, High-Density, Eighth-Brick

Low Proﬁ le DC-DC Converters

MDC_UCE.C02 Page 10 of 17

www.murata-ps.com/support

MECHANICAL SPECIFICATIONS

DOSA-Compliant

INPUT/OUTPUT CONNECTIONS

Pin Function P32

1 +Vin

2 On/Off Control

3 –Vin

4 –Vout

5 –Sense

6 Trim

7 +Sense

8 +Vout

Third Angle Projection

Dimensions are in inches (mm 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 ± 2˚

Bottom view

Standard pin length is shown. Please refer to the Part Number Structure

for special order pin lengths.

2.30 (58.4)

2.00 (50.8)

0.37 max

(9.4)

0.18

(4.6)

0.300

(7.62)

0.300

(7.62)

0.15

(3.81)

0.900

(22.9)

0.015 minimum clearance

between standoffs and

highest component

PINS 1-3, 5-7:

0.040±0.001 (1.016±0.025) dia.

PINS 4, 8:

0.062±0.001 (1.575±0.025) dia.

Pin 8

Open Frame

Without Baseplate

PIN Shoulder 1-3, 5-7:

ĳ0.078±0.003 (1.98±0.076)

PIN Shoulder 4,8:

ĳ0.100±0.003 (2.54±0.076)

UCE Series

Isolated, High-Density, Eighth-Brick

Low Proﬁ le DC-DC Converters

MDC_UCE.C02 Page 11 of 17

www.murata-ps.com/support

MECHANICAL SPECIFICATIONS

Bottom view

0.300

(7.62)

0.300

(7.62)

0.15

(3.81)

0.900

(22.9)

Screw length must not

go through baseplate.

PINS 1-3, 5-7:

0.040±0.001 (1.016±0.025) dia.

PINS 4, 8:

0.062±0.001 (1.575±0.025) dia.

Pin 8

0.015 minimum clearance

between standoffs and

highest component

With Baseplate

0.50

(12.7)

0.600

(15.24)

0.900

(22.9)

2.00 (50.8)

2.30 (58.4)

0.18

(4.6)

M3 threaded insert 2

places, See notes 1&2

1. M3 screw used to bolt unit's baseplate to other surfaces (such as heatsink)

must not exceed 0.118'' (3mm) depth below the surface of baseplate

2. Applied torque per screw should not exceed 5.3 In-lb (0.6 Nm)

PIN Shoulder 1-3, 5-7:

ĳ0.078±0.003 (1.98±0.076)

PIN Shoulder 4,8:

ĳ0.100±0.003 (2.54±0.076)

Third Angle Projection

Dimensions are in inches (mm 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 ± 2˚

Standard pin length is shown. Please refer to the Part Number Struc-

ture for special order pin lengths.

DOSA-Compliant

INPUT/OUTPUT CONNECTIONS

Pin Function P32

1 +Vin

2 On/Off Control

3 –Vin

4 –Vout

5 –Sense

6 Trim

7 +Sense

8 +Vout

UCE Series

Isolated, High-Density, Eighth-Brick

Low Proﬁ le DC-DC Converters

MDC_UCE.C02 Page 12 of 17

www.murata-ps.com/support

Input Fusing

Certain applications and/or safety agencies may require fuses at the inputs of

power conversion components. Fuses should also be used when there is the

possibility of sustained input voltage reversal which is not current-limited. For

greatest safety, we recommend a fast blow fuse installed in the ungrounded

input supply line with a value which is approximately twice the maximum line

current, calculated at the lowest input voltage.

The installer must observe all relevant safety standards and regulations. For

safety agency approvals, install the converter in compliance with the end-user

safety standard.

Input Reverse-Polarity Protection

If the input voltage polarity is reversed, an internal body diode will become

forward biased and likely draw excessive current from the power source. If this

source is not current-limited or the circuit appropriately fused, it could cause

permanent damage to the converter. Please be sure to install a properly

rated external input fuse.

Input Under-Voltage Shutdown and Start-Up Threshold

Under normal start-up conditions, converters will not begin to regulate properly

until the rising input voltage exceeds and remains at the Start-Up Threshold

Voltage (see Speciﬁ cations). Once operating, converters will not turn off until

the input voltage drops below the Under-Voltage Shutdown Limit. Subsequent

restart will not occur until the input voltage rises again above the Start-Up

Threshold. This built-in hysteresis prevents any unstable on/off operation at a

single input voltage.

Users should be aware however of input sources near the Under-Voltage

Shutdown whose voltage decays as input current is consumed (such as

capacitor inputs), the converter shuts off and then restarts as the external

capacitor recharges. Such situations could oscillate. To prevent this, make

sure the operating input voltage is well above the UV Shutdown voltage AT ALL

TIMES.

Start-Up Delay

Assuming that the output current is set at the rated maximum, the Vin to Vout

Start-Up Time (see Speciﬁ cations) is the time interval between the point when

the rising input voltage crosses the Start-Up Threshold and the fully loaded

regulated output voltage enters and remains within its speciﬁ ed regulation

band. Actual measured times will vary with input source impedance, external

input capacitance, input voltage slew rate and ﬁ nal value of the input voltage

as it appears at the converter.

These converters include a soft start circuit to moderate the duty cycle of the

PWM controller at power up, thereby limiting the input inrush current.

The On/Off Remote Control interval from inception to Vout regulated

assumes that the converter already has its input voltage stabilized above the

Start-Up Threshold before the On command. The interval is measured from the

On command until the output enters and remains within its speciﬁ ed regulation

band. The speciﬁ cation assumes that the output is fully loaded at maximum

rated current.

TECHNICAL NOTES Input Source Impedance

These converters will operate to speciﬁ cations without external components,

assuming that the source voltage has very low impedance and reasonable

input voltage regulation. Since real-world voltage sources have ﬁ nite imped-

ance, performance is improved by adding external ﬁ lter components. Some-

times only a small ceramic capacitor is sufﬁ cient. Since it is difﬁ cult to totally

characterize all applications, some experimentation may be needed. Note that

external input capacitors must accept high speed switching currents.

Because of the switching nature of DC-DC converters, the input of these

converters must be driven from a source with both low AC impedance and

adequate DC input regulation. Performance will degrade with increasing input

inductance. Excessive input inductance may inhibit operation. The DC input

regulation speciﬁ es that the input voltage, once operating, must never degrade

below the Shut-Down Threshold under all load conditions. Be sure to use

adequate trace sizes and mount components close to the converter.

I/O Filtering, Input Ripple Current and Output Noise

All models in this converter series are tested and speciﬁ ed for input reﬂ ected

ripple current and output noise using designated external input/output compo-

nents, circuits and layout as shown in the ﬁ gures below. External input capaci-

tors (Cin in the ﬁ gure) serve primarily as energy storage elements, minimizing

line voltage variations caused by transient IR drops in the input conductors.

Users should select input capacitors for bulk capacitance (at appropriate

frequencies), low ESR and high RMS ripple current ratings. In the ﬁ gure below,

the Cbus and Lbus components simulate a typical DC voltage bus. Your speciﬁ c

system conﬁ guration may require additional considerations. Please note that

the values of Cin, Lbus and Cbus will vary according to the speciﬁ c converter

model.

In critical applications, output ripple and noise (also referred to as periodic

and random deviations or PARD) may be reduced by adding ﬁ lter elements

such as multiple external capacitors. Be sure to calculate component tempera-

ture rise from reﬂ ected AC current dissipated inside capacitor ESR.

Figure 2. Measuring Input Ripple Current

BUS

= 33μF, ESR < 700mΩ @ 100kHz

BUS

= 220μF, ESR < 100mΩ @ 100kHz

BUS

= 12μH

+VIN

−VIN

CURRENT

PROBE

OSCILLOSCOPE

–

UCE Series

Isolated, High-Density, Eighth-Brick

Low Proﬁ le DC-DC Converters

MDC_UCE.C02 Page 13 of 17

www.murata-ps.com/support

Floating Outputs

Since these are isolated DC-DC converters, their outputs are “ﬂ oating” with

respect to their input. The essential feature of such isolation is ideal ZERO

CURRENT FLOW between input and output. Real-world converters however do

exhibit tiny leakage currents between input and output (see Speciﬁ cations).

These leakages consist of both an AC stray capacitance coupling component

and a DC leakage resistance. When using the isolation feature, do not allow

the isolation voltage to exceed speciﬁ cations. Otherwise the converter may

be damaged. Designers will normally use the negative output (-Output) as

the ground return of the load circuit. You can however use the positive output

(+Output) as the ground return to effectively reverse the output polarity.

Minimum Output Loading Requirements

All models regulate within speciﬁ cation and are stable under no load to full

load conditions. Operation under no load might however slightly increase

output ripple and noise.

Thermal Shutdown

To protect against thermal overstress, these converters include thermal

shutdown circuitry. If environmental conditions cause the temperature of the

DC-DC’s to rise above the Operating Temperature Range up to the shutdown

temperature, an on-board electronic temperature sensor will power down

the unit. When the temperature decreases below the turn-on threshold, the

converter will automatically restart. There is a small amount of hysteresis to

prevent rapid on/off cycling. The temperature sensor is typically located adja-

cent to the switching controller, approximately in the center of the unit. See the

Performance and Functional Speciﬁ cations.

CAUTION: If you operate too close to the thermal limits, the converter may

shut down suddenly without warning. Be sure to thoroughly test your applica-

tion to avoid unplanned thermal shutdown.

Temperature Derating Curves

The graphs in this data sheet illustrate typical operation under a variety of

conditions. The Derating curves show the maximum continuous ambient air

temperature and decreasing maximum output current which is acceptable

under increasing forced airﬂ ow measured in Linear Feet per Minute (“LFM”).

Note that these are AVERAGE measurements. The converter will accept brief

increases in current or reduced airﬂ ow as long as the average is not exceeded.

Note that the temperatures are of the ambient airﬂ ow, not the converter

itself which is obviously running at higher temperature than the outside air.

Also note that very low ﬂ ow rates (below about 25 LFM) are similar to “natural

convection,” that is, not using fan-forced airﬂ ow.

Murata Power Solutions makes Characterization measurements in a closed

cycle wind tunnel with calibrated airﬂ ow. We use both thermocouples and an

infrared camera system to observe thermal performance. As a practical matter,

it is quite difﬁ cult to insert an anemometer to precisely measure airﬂ ow in

most applications. Sometimes it is possible to estimate the effective airﬂ ow if

you thoroughly understand the enclosure geometry, entry/exit oriﬁ ce areas and

the fan ﬂ owrate speciﬁ cations.

CAUTION: If you exceed these Derating guidelines, the converter may have

an unplanned Over Temperature shut down. Also, these graphs are all collected

near Sea Level altitude. Be sure to reduce the derating for higher altitude.

Output Overvoltage Protection (OVP)

This converter monitors its output voltage for an over-voltage condition. If

the output exceeds OVP limits, the sensing circuit will power down the unit,

and the output voltage will decrease. After a time-out period, the PWM will

automatically attempt to restart, causing the output voltage to ramp up to its

rated value. It is not necessary to power down and reset the converter for the

automatic OVP-recovery restart.

If the fault condition persists and the output voltage climbs to excessive

levels, the OVP circuitry will initiate another shutdown cycle. This on/off cycling

is referred to as “hiccup” mode.

Output Fusing

The converter is extensively protected against current, voltage and temperature

extremes. However your application circuit may need additional protection. In

the extremely unlikely event of output circuit failure, excessive voltage could be

applied to your circuit. Consider using appropriate external protection.

Output Current Limiting

As soon as the output current increases to approximately 125% to 150% of

its maximum rated value, the DC-DC converter will enter a current-limiting

mode. The output voltage will decrease proportionally with increases in output

current, thereby maintaining a somewhat constant power output. This is also

commonly referred to as power limiting.

Current limiting inception is deﬁ ned as the point at which full power falls

below the rated tolerance. See the Performance/Functional Speciﬁ cations.

Note particularly that the output current may brieﬂ y rise above its rated value

in normal operation as long as the average output power is not exceeded. This

enhances reliability and continued operation of your application. If the output

current is too high, the converter will enter the short circuit condition.

Output Short Circuit Condition

When a converter is in current-limit mode, the output voltage will drop as the

output current demand increases. If the output voltage drops too low (approxi-

mately 98% of nominal output voltage for most models), the magnetically

coupled voltage used to develop the PWM bias voltage will also drop, thereby

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

restart, causing the output voltage to begin rising to its appropriate value.

Figure 3. Measuring Output Ripple and Noise (PARD)

C1 = 1μF

C2 = 10μF

LOAD 2-3 INCHES (51-76mm) FROM MODULE

C2 R

LOAD

SCOPE

+VOUT

+SENSE

−SENSE

−VOUT

UCE Series

Isolated, High-Density, Eighth-Brick

Low Proﬁ le DC-DC Converters

MDC_UCE.C02 Page 14 of 17

www.murata-ps.com/support

If the short-circuit condition persists, another shutdown cycle will initiate.

This rapid on/off cycling is called “hiccup mode.” The hiccup cycling reduces

the average output current, thereby preventing excessive internal temperatures

and/or component damage.

The “hiccup” system differs from older latching short circuit systems

because you do not have to power down the converter to make it restart. The

system will automatically restore operation as soon as the short circuit condi-

tion is removed.

Remote Sense Input

Use the Sense inputs with caution. Sense is normally connected at the load.

Sense inputs compensate for output voltage inaccuracy delivered at the load.

This is done by correcting IR voltage drops along the output wiring and the

current carrying capacity of PC board etch. This output drop (the difference

between Sense and Vout when measured at the converter) should not exceed

0.5V. Consider using heavier wire if this drop is excessive. Sense inputs also

improve the stability of the converter and load system by optimizing the control

loop phase margin.

Note: The Sense input and power Vout lines are internally connected through

low value resistors to their respective polarities so that the converter can

operate without external connection to the Sense. Nevertheless, if the Sense

function is not used for remote regulation, the user should connect +Sense to

+Vout and –Sense to –Vout at the converter pins.

The remote Sense lines carry very little current. They are also capacitively

coupled to the output lines and therefore are in the feedback control loop to

regulate and stabilize the output. As such, they are not low impedance inputs

and must be treated with care in PC board layouts. Sense lines on the PCB

should run adjacent to DC signals, preferably Ground. In cables and discrete

wiring, use twisted pair, shielded tubing or similar techniques.

Any long, distributed wiring and/or signiﬁ cant inductance introduced into the

Sense control loop can adversely affect overall system stability. If in doubt, test

your applications by observing the converter’s output transient response during

step loads. There should not be any appreciable ringing or oscillation. You

may also adjust the output trim slightly to compensate for voltage loss in any

external ﬁ lter elements. Do not exceed maximum power ratings.

Please observe Sense inputs tolerance to avoid improper operation:

[Vout(+) −Vout(-)] − [Sense(+) −Sense(-)] ≤ 10% of Vout

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

Sense pin. Therefore excessive voltage differences between Vout and Sense

together with trim adjustment of the output can cause the overvoltage protec-

tion circuit to activate and shut down the output.

Power derating of the converter is based on the combination of maximum

output current and the highest output voltage. Therefore the designer must

ensure:

(Vout at pins) x (Iout) ≤ (Max. rated output power)

Trimming the Output Voltage

The Trim input to the converter allows the user to adjust the output voltage

over the rated trim range (please refer to the Speciﬁ cations). In the trim equa-

tions and circuit diagrams that follow, trim adjustments use either a trimpot or

a single ﬁ xed resistor connected between the Trim input and either the +Sense

or –Sense terminals. (On some converters, an external user-supplied precision

DC voltage may also be used for trimming). Trimming resistors should have a

low temperature coefﬁ cient (±100 ppm/deg.C or less) and be mounted close

to the converter. Keep leads short. If the trim function is not used, leave the

trim unconnected. With no trim, the converter will exhibit its speciﬁ ed output

voltage accuracy.

There are two CAUTIONs to observe for the Trim input:

CAUTION: To avoid unplanned power down cycles, do not exceed EITHER

the maximum output voltage OR the maximum output power when setting the

trim. Be particularly careful with a trimpot. If the output voltage is excessive,

the OVP circuit may inadvertantly shut down the converter. If the maximum

power is exceeded, the converter may enter current limiting. If the power is

exceeded for an extended period, the converter may overheat and encounter

overtemperature shut down.

CAUTION: Be careful of external electrical noise. The Trim input is a senstive

input to the converter’s feedback control loop. Excessive electrical noise may

cause instability or oscillation. Keep external connections short to the Trim

input. Use shielding if needed.

Figure 4. Remote Sense Circuit Conﬁ guration

LOAD

Contact and PCB resistance

losses due to IR drops

Contact and PCB resistance

losses due to IR drops

+VOUT

+SENSE

TRIM

−

SENSE

-VOUT

+VIN

ON/OFF

CONTROL

−VIN

Sense Current

IOUT

Sense Return

IOUT Return

UCE Series

Isolated, High-Density, Eighth-Brick

Low Proﬁ le DC-DC Converters

MDC_UCE.C02 Page 15 of 17

www.murata-ps.com/support

Trimming by Using an External Voltage Source

1. The easiest way to trim the output using an external voltage source is to

drive the Trim pin directly from a variable source. The following equation can

be used to calculate the voltage at the Trim pin.

Vo is the output voltage you want; Vonominal is the nominal output voltage;

Vtrim is the voltage that should appear at the trim pin.

2. If the purpose of trimming is to compensate voltage drop of power path

from converter to the Load, you may separately connect the sense pin directly

to the load. It’s much easier than real time adjusting trim voltage.

3. CAUTION: To avoid unplanned power down cycles, do not exceed EITHER

the maximum output voltage OR the maximum output power when setting

the trim. If the output voltage is excessive, the OVP circuit may shut down the

converter. If the maximum power is exceeded, the converter may enter current

limiting. If the power is exceeded for an extended period, the converter may

overheat and encounter overtemperature shut down. Be careful of external

electrical noise. The Trim input is a sensitive input to the converter’s feedback

control loop. Excessive electrical noise may cause instability or oscillation.

Vonominal

Vtrim = 2 x 1.225 x − 1.225

Where,

Δ = | (VNOM − VOUT) / VNOM |

VNOM is the nominal, untrimmed output voltage.

VOUT is the desired new output voltage.

Do not exceed the speciﬁed trim range or maximum power ratings when adjusting trim.

Use 1% precision resistors mounted close to the converter on short leads.

Trim Down

Connect trim resistor between

trim pin and −Sense

5.11

RTrimDn (k Ω) = − 10.22

Trim Up

Connect trim resistor between

trim pin and +Sense

1.225 × Δ

5.11 × VNOM × (1+Δ)

RTrimUp (k Ω) = − 10.22

− 5.11

Trim Equations

Figure 5. Trimming with an external source

LOAD

+VOUT

+VIN

–VIN

ON/OFF

CONTROL

TRIM

+SENSE

–VOUT

External

source

–SENSE

–

UCE Series

Isolated, High-Density, Eighth-Brick

Low Proﬁ le DC-DC Converters

MDC_UCE.C02 Page 16 of 17

www.murata-ps.com/support

Remote On/Off Control

On the input side, a remote On/Off Control can be speciﬁ ed with either positive

or negative logic logic.

Positive: Models equipped with positive logic are enabled when the On/Off

pin is left open or is pulled high to +Vin with respect to –Vin. An internal bias

current causes the open pin to rise to approximately +15V. Some models will

also turn on at lower intermediate voltages (see Speciﬁ cations). Positive-logic

devices are disabled when the On/Off is grounded or brought to within a low

voltage (see Speciﬁ cations) with respect to –Vin.

Negative: Models with negative logic are on (enabled) when the On/Off is

grounded or brought to within a low voltage (see Speciﬁ cations) with respect to

–Vin. The device is off (disabled) when the On/Off is left open or is pulled high

to approximately +15V with respect to –Vin.

Dynamic control of the On/Off function should be able to sink the speci-

ﬁ ed signal current when brought low and withstand appropriate voltage

when brought high. Be aware too that there is a ﬁ nite time in milliseconds

(see Speciﬁ cations) between the time of On/Off Control activation and stable,

regulated output. This time will vary slightly with output load type and current

and input conditions.

There are two CAUTIONs for the On/Off Control:

CAUTION: While it is possible to control the On/Off with external logic if

you carefully observe the voltage levels, the preferred circuit is either an open

drain/open collector transistor, a switch or a relay (which can thereupon be

controlled by logic) returned to negative Vin.

CAUTION: Do not apply voltages to the On/Off pin when there is no input

power voltage. Otherwise the converter may be permanently damaged.

Output Capacitive Load

These converters do not require external capacitance added to achieve rated

speciﬁ cations. Users should only consider adding capacitance to reduce switch-

ing noise and/or to handle spike current step loads. Install only enough capaci-

tance to achieve noise objectives. Excess external capacitance may cause

regulation problems, slower transient response and possible instability. Proper

wiring of the Sense inputs will improve these factors under capacitive load.

The maximum rated output capacitance and ESR speciﬁ cation is given for a

capacitor installed immediately adjacent to the converter. Any extended output

wiring or smaller wire gauge or less ground plane may tolerate somewhat higher

capacitance. Also, capacitors with higher ESR may use a larger capacitance.

Figure 6. Trim Connections Using A Trimpot

Figure 9. Trim Connections To Decrease Output VoltagesFigure 7. Trim Connections To Increase Output Voltages

LOAD

+VOUT

+VIN

–VIN

ON/OFF

CONTROL

TRIM

+SENSE

–VOUT

–SENSE

LOAD

RTRIM DOWN

+VOUT

+VIN

–VIN

ON/OFF

CONTROL TRIM

+SENSE

–VOUT

–SENSE

LOAD

RTRIM UP

+VOUT

+VIN

–VIN

ON/OFF

CONTROL

TRIM

+SENSE

–VOUT

–SENSE

Trim Circuits

Figure 8. Driving the On/Off Control Pin (suggested circuit)

ON/OFF

CONTROL

-VIN

+VCC

Connect sense to its respective VOUT pin if sense is not used with a remote load.

UCE Series

Isolated, High-Density, Eighth-Brick

Low Proﬁ le DC-DC Converters

MDC_UCE.C02 Page 17 of 17

www.murata-ps.com/support

Murata Power Solutions, Inc. makes no representation that the use of its products in the circuits described herein, or the use of other

technical information contained herein, will not infringe upon existing or future patent rights. The descriptions contained herein do not imply

the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Speciﬁ cations are subject to change without

Murata Power Solutions, Inc.

11 Cabot Boulevard, Mansﬁ eld, MA 02048-1151 U.S.A.

ISO 9001 and 14001 REGISTERED

This product is subject to the following operating requirements

and the Life and Safety Critical Application Sales Policy:

Refer to: http://www.murata-ps.com/requirements/

Figure 10. Vertical Wind Tunnel

IR Video

Camera

IR Transparent

optical window Variable

speed fan

Heating

element

Ambient

temperature

sensor

Airﬂow

collimator

Precision

low-rate

anemometer

3” below UUT

Unit under

test (UUT)

Vertical Wind Tunnel

Murata Power Solutions employs a computer controlled

custom-designed closed loop vertical wind tunnel, infrared

video camera system, and test instrumentation for accurate

airﬂ ow and heat dissipation analysis of power products.

The system includes a precision low ﬂ ow-rate anemometer,

variable speed fan, power supply input and load controls,

temperature gauges, and adjustable heating element.

The IR camera monitors the thermal performance of the

Unit Under Test (UUT) under static steady-state conditions. A

special optical port is used which is transparent to infrared

wavelengths.

Both through-hole and surface mount converters are

soldered down to a 10"x 10" host carrier board for realistic

heat absorption and spreading. Both longitudinal and trans-

verse airﬂ ow studies are possible by rotation of this carrier

board since there are often signiﬁ cant differences in the heat

dissipation in the two airﬂ ow directions. The combination of

adjustable airﬂ ow, adjustable ambient heat, and adjustable

Input/Output currents and voltages mean that a very wide

range of measurement conditions can be studied.

The collimator reduces the amount of turbulence adjacent

to the UUT by minimizing airﬂ ow turbulence. Such turbu-

lence inﬂ uences the effective heat transfer characteristics

and gives false readings. Excess turbulence removes more

heat from some surfaces and less heat from others, possibly

causing uneven overheating.

Both sides of the UUT are studied since there are different

thermal gradients on each side. The adjustable heating element

and fan, built-in temperature gauges, and no-contact IR camera mean

that power supplies are tested in real-world conditions.