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For full details go to
www.murata-ps.com/rohs
ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 1 of 26
s
FEATURES
RoHS compliant
New 1/8-brick package, 1/4-brick pinout
in through-hole or SMT version
0.89 x 2.22 x 0.36 in. (22.6 x 56.4 x 9.1mm)
Output current: 1.25-20 Amps
Output voltages: 1.5V to 48V
Input voltage: 12V, 24V and 48V nominal
Interleaved, synchronous-rectifi er
topology delivers:
Outstanding effi ciency (to 94%)
Low noise
Stable no-load operation
No output reverse conduction
Excellent thermal performance
On/off control, trim and sense pins
Fully isolated (2250Vdc BASIC)
Fully I/O protected; Thermal shutdown
Certifi ed to UL/IEC/EN 60950-1 and CAN/CSA
C22.2 No.60950-1, 2nd edition
Lead-free construction/attach
Measuring just 0.89 × 2.22 × 0.36 inches (22.6
× 56.4 × 9.1mm), these open-frame, low-profi le
E-bricks fi t the industry-standard quarter-brick
footprint. Now you can “cut-and-paste” the layout
from your last Q-brick design to save time and save
44% board space (1.86 square inches versus 3.3)
in the process.
From a 9-18V, 18-36V or 36-75V input, ULEs
deliver 1.5 to 48 Volt outputs with current up to
20 Amps. They employ an interleaved, synchro-
nous-rectifi er topology that exploits 100% of their
duty cycle. They simultaneously achieve high
effi ciency, low noise, tight line/load regulation, and
quick step response.
An open-frame design, high effi ciency, low-on-
resistance FETs, and planar magnetics embedded
in heavy-copper pc boards all contribute to
impressive thermal derating. The ULEs feature set
includes high isolation (2250Vdc, 48V models),
input pi fi lters, input undervoltage shutdown,
output overvoltage protection, current limiting,
short-circuit protection, and thermal shutdown. The
standard footprint carries VOUT trim, on/off control,
and sense pins (sense pins are not available on
12V or higher models).
All ULE E-Bricks are certifi ed to the BASIC-
insulation requirements of UL/EN/IEC60950-1,
2nd edition, and all “D48” models (36-75V input
ranges) carry the CE mark. Safety certifi cations,
EMC compliance testing and qualifi cation testing
are available.
PRODUCT OVERVIEW
The ULE Series "Eighth-Brick" DC/DC Converters are high-current isolated
power converters designed for use in high-density system boards.
Typical unit
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PART NUMBER STRUCTURE
ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 2 of 26
PERFORMANCE SPECIFICATIONS SUMMARY AND ORDERING GUIDE
Model Family
Output Input Effi ciency
Package
(Case, Pinout)
VOUT
(V)
IOUT
(A)
Power
(W)
R/N (mVp-p) Regulation (Max.) VIN Nom.
(V)
Range
(V)
IIN no
load
(mA)
IIN full
load
(A) Min. Typ.Typ. Max. Line Load
ULE-1.5/20-D24P-C 1.5 20 30 25 60 ±0.15% ±0.15% 24 18-36 40 1.42 86.0% 88.0% C56, C52, P32
ULE-1.5/20-D48N-C 1.5 20 30 25 60 ±0.15% ±0.15% 48 36-75 40 0.74 84.0% 84.5% C56, C52, P32
ULE-1.8/20-D24P-C 1.8 20 36 40 80 ±0.25% ±0.25% 24 18-36 40 1.74 84.5% 86.0% C56, C52, P32
ULE-1.8/20-D48N-C 1.8 20 36 40 80 ±0.25% ±0.25% 48 36-75 40 0.87 84.5% 86.5% C56, C52, P32
ULE-2.5/20-D24P-C 2.5 20 50 30 50 ±0.05% ±0.05% 24 18-36 95 2.35 87.0% 88.5% C56, C52, P32
ULE-2.5/20-D48N-C 2.5 20 50 50 75 ±0.05% ±0.1% 48 36-75 55 1.17 88.0% 89.0% C56, C52, P32
ULE-3.3/20-D12P-C 3.3 20 66 60 100 ±0.05% ±0.05% 12 9-18 100 6.15 88.9% 89.4% C56, C52, P32
ULE-3.3/20-D24P-C 3.3 20 66 50 80 ±0.05% ±0.05% 24 18-36 60 3.09 88.0% 89.0% C56, C52, P32
ULE-3.3/20-D48N-C 3.3 20 66 50 100 ±0.1% ±0.25% 48 36-75 60 1.54 87.0% 89.0% C56, C52, P32
ULE-5/10-D12P-C 5 10 50 60 125 ±0.05% ±0.05% 12 9-18 160 4.63 87.0% 90.0% C56, C52, P32
ULE-5/12-D24P-C 512 60 50 100 ±0.1% ±0.25% 24 19-36 160 2.78 88.0% 90.0% C56, C52, P32
ULE-5/12-D48N-C 5 12 60 50 100 ±0.1% ±0.25% 48 36-75 90 1.38 88.5% 90.5% C56, C52, P32
ULE-12/4.2-D24P-C 12 4.2 50.4 50 150 ±0.05% ±0.075% 24 18-36 55 2.31 89.5% 91.0% C56, C52, P32
ULE-12/4.2-D48N-C 12 4.2 50.4 50 150 ±0.05% ±0.075% 48 36-75 55 1.14 91.0% 92.0% C56, C52, P32
ULE-24/3-D48N-C 24 3 72 400 700 ±0.3% ±1.25% 48 36-75 45 1.63 90.8% 92.0% C56, C52, P32
ULE-48/1.25-D48N-C 48 1.25 60 640 750 ±0.175% ±3.2% 48 36-75 75 1.35 91.0% 92.5% C56, P32
Please refer to the full model number structure for additional ordering part numbers and
options.
All specifi cations are at nominal line voltage and full load, +25ºC unless otherwise noted.
See detailed specifi cations.
If VIN = 19−20V, IOUT = 8A Max.
Min. load = 10%.
If VIN = 9−10V, IOUT = 18A Max.
Maximum Rated Output
Current in Amps
Eighth-Brick Package
Output Confi guration:
U = Unipolar/Single Output
Nominal Output Voltage
U LE -/D48-1.5 20 N M
Input Voltage Range:
D12 = 12V nominal
D24 = 24V nominal
D48 = 48V nominal
Surface (Gullwing) Mount Package 20
C
RoHS-6 hazardous substance compliant
Does not claim EU RoHS exemption 7b, lead in solder
-
Lx
Remote On/Off Control Polarity:
P = Positive polarity (standard for D12 and
D24 models, optional special order for D48 models)
N = Negative polarity (standard for D48 models,
optional special order for D12 and D24 models)
See notes on page 5.
(Through-hole packages only)
Blank = standard length 0.180˝ (4.6mm)
L1 = Pin length 0.110±0.010˝ (2.79±0.25mm)*
L2 = Pin length 0.145±0.010˝ (3.68±0.25mm)*
Pin Length Option
Note:
Some model number combinations
may not be available. Please contact
Murata Power Solutions.
*Special quantity order is required;
no sample quantities available.
www.murata-ps.com/support
ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 3 of 26
See notes on page 5.
INPUT CHARACTERISTICS
Model Family
Start-up
threshold
Min.
(V)
Under
Voltage
Shut-
down
(V)
Refl ected
(back)
Ripple
Current
(mA)
Load Current Inter-
nal
Input
Filter
Type
Reverse
Polarity
Protec-
tion
Remote On/Off Control Start-up Time
Full
Load
Condi-
tions
Inrush
Transient
Conditions
(A2sec)
Output
Short
Circuit
No Load
(mA)
Low
Line
(A)
Standby
Mode
(mA)
Cur-
rent
(mA)
Positive
Logic
“P” model
suffi x
Negative
Logic
“N” model
suffi x
VIN to VOUT
regulated
(Max.)
mSec
Remote On/Off
to VOUT regu-
lated (Max.)
mSec
ULE-1.5/20-D24 17.0 16.0
15−45,
model
dependent
See
Ordering
Guide
0.5−1
40−250
model
depen-
dent
40−160
model
depen-
dent
1.96
1−8
model
depen-
dent
L-C
None,
install
external
fuse
1.0
OFF=Ground pin
to +0.8V max.
ON=open or
3.5V to +13.5V
max.
OFF=open or
+3.5V to
+13.5V max.
ON=Ground pin
to +0.8V max.
6-90, model
dependent
6-90, model
dependent
ULE-1.5/20-D48 34.0 33.0 0.98
ULE-1.8/20-D24 17.0 16.0 2.33
ULE-1.8/20-D48 33.0 31.0 1.16
ULE-2.5/20-D24 17.0 16.0 3.23
ULE-2.5/20-D48 33.0 32.0 1.55
ULE-3.3/20-D12 8.5 8.0 7.42
ULE-3.3/20-D24 17.0 16.0 4.10
ULE-3.3/20-D48 34.5 33.5 2.05
ULE-5/10-D12 8.5 8.0 6.14
ULE-5/12-D24 19.0 17.5 3.30
ULE-5/12-D48 34.5 33.5 1.82
ULE-12/4.2-D24 17.0 16.0 3.04
ULE-12/4.2-D48 35.0 34.0 1.51
ULE-24/3-D48 35.0 33.0 2.17 150 150
ULE-48/1.25-D48 35.0 33.5 1.46 6-90 6-90
OUTPUT CHARACTERISTICS
Model Family
VOUT
(V)
VOUT
Accuracy
50% Load
% of VNOM
Capacitive Loading
Max.
Low ESR <0.02Ω Max.
resistive load
(μF)
Adjustment
Range
Temperature
Coeffi cient
Minimum
Loading
Remote Sense
Compensation
Ripple/Noise
(20 MHz
bandwidth)
Line/Load
Regulation Effi ciency
Current Limit
Inception
98% of VOUT
after warmup
(A)
ULE-1.5/20-D24 1.5
±1 to ±2
of VNOM,
model
dependent
10,000
−20 to +10%
of VNOM, model
dependent
±0.02% of
VOUT range/°C
No Minimum
Load18
+10%
See Ordering Guide
24
ULE-1.5/20-D48 1.5 24
ULE-1.8/20-D24 1.8 24
ULE-1.8/20-D48 1.8 25
ULE-2.5/20-D24 2.5 24
ULE-2.5/20-D48 2.5 24
ULE-3.3/20-D12 3.3 24
ULE-3.3/20-D24 3.3 24
ULE-3.3/20-D48 3.3 26
ULE-5/10-D12 5 13
ULE-5/12-D24 5 15
ULE-5/12-D48 5 16
ULE-12/4.2-D24 12 2000 none 6
ULE-12/4.2-D48 12 6.25
ULE-24/3-D48 24 680 300 mA 10% 4.25
ULE-48/1.25-D48 48 470 No Minimum none 2.5
FUNCTIONAL SPECIFICATIONS
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ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 4 of 26
ISOLATION CHARACTERISTICS
Model Family
Input to
Output
Min.
(V)
Isolation
Resistance
(MΩ)
Isolation
Capacitance
(pF)
Isolation
Safety Rating
ULE-1.5/20-D24
2000-
2250 min.,
model
dependent
100
1750
Basic
Insulation
ULE-1.5/20-D48
ULE-1.8/20-D24
ULE-1.8/20-D48
ULE-2.5/20-D24
ULE-2.5/20-D48
ULE-3.3/20-D12
ULE-3.3/20-D24
ULE-3.3/20-D48
ULE-5/10-D12 470
ULE-5/12-D24
ULE-5/12-D48
1750ULE-12/4.2-D24
ULE-12/4.2-D48
ULE-24/3-D48 2000
ULE-48/1.25-D48 1500
DYNAMIC CHARACTERISTICS
Model Family
Dynamic Load Response
(50-75-50% load step)
Switching
Frequency
KHz
ULE-1.5/20-D24 100µSec to ±1.5% of fi nal value 280±15
ULE-1.5/20-D48 100µSec to ±1.5% of fi nal value 280±15
ULE-1.8/20-D24 100µSec to ±1.5% of fi nal value 340±15
ULE-1.8/20-D48 100µSec to ±1.5% of fi nal value 340±15
ULE-2.5/20-D24 150µSec to ±1% of fi nal value 385±15
ULE-2.5/20-D48 80µSec to ±1.5% of fi nal value 385±45
ULE-3.3/20-D12 150µSec to ±1.25% of fi nal value 310±15
ULE-3.3/20-D24 150µSec to ±1.5% of fi nal value 385±15
ULE-3.3/20-D48 150µSec to ±1% of fi nal value 365±15
ULE-5/10-D12 75µSec to ±2% of fi nal value 325±15
ULE-5/12-D24 75µSec to ±2% of fi nal value 450±15
ULE-5/12-D48 100µSec to ±1% of fi nal value 450±15
ULE-12/4.2-D24 150µSec to ±1.25% of fi nal value 400±15
ULE-12/4.2-D48 150µSec to ±1.25% of fi nal value 380±15
ULE-24/3-D48 200µSec to ±2% of fi nal value 240±30
ULE-48/1.25-D48 200µSec to ±1% of fi nal value 250±15
*No derating is required up to 85°C.
See notes on page 5.
MISCELLANEOUS CHARACTERISTICS
Model Family
Calculated
MTBF
Operating Temperature Range
Operating PCB
Temperature
(no derating)
Storage
Temperature
Range
Thermal
Protection/
Shutdown
Short
Circuit
Current
Overvoltage
Protection
via magnetic
feedback
(V)
Short Circuit
Protection
Method
Short Circuit
Duration
Relative
Humidity
See
derating curves
ULE-1.5/20-D24
TBC −40 to +85ºC with derating −40 to
+105ºC
−55 to
+125ºC
+105 to
+125ºC,
model
dependent
3A 2.3
Current
limiting,
hiccup
autorestart.
Remove
overload for
recovery
Continuous,
output
shorted to
ground.
No damage.
To
+85ºC/85%
non-
condensing
ULE-1.5/20-D48 3A 2.0
ULE-1.8/20-D24 3A 2.3
ULE-1.8/20-D48 3A 2.3
ULE-2.5/20-D24 3A 3.5
ULE-2.5/20-D48 3A 3.0
ULE-3.3/20-D12 300mA 3.96
ULE-3.3/20-D24 3A 3.96
ULE-3.3/20-D48 3A 3.96
ULE-5/10-D12 5A 6.0
ULE-5/12-D24 5A 6.0
ULE-5/12-D48 2A 6.4
ULE-12/4.2-D24 3A 15.0
ULE-12/4.2-D48 3A 14.0
ULE-24/3-D48* 0.65A 28.0
ULE-48/1.25-D48 500mA 55.0
16
12
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Input Voltage:
Continuous:
12 Volt input models 18 Volts
24 Volt input models 36 Volts
48 Volt input models 75 Volts
Transient (100 mSec. Max.)
12 Volt input models 25 Volts
24 Volt input models 50 Volts
48 Volt input models 100 Volts
On/Off Control (pin 2) See specifi cations
Input Reverse Polarity Protection 5 Amps, 10 sec. max.
Output Overvoltage Protection Magnetic feedback. See note (7).
Output Current * Current-limited. Devices can with stand
sustained short circuit without damage.
Storage Temperature –55 to +125°C.
Lead Temperature Refer to solder profi le.
These 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.
Absolute Maximum Ratings
* The outputs are not intended to sink reverse current.
ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 5 of 26
1. All models are tested and specifi ed with external 1||10 µF ceramic/tantalum output
capacitors and a 22 µF 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 tantalum, CBUS=220 µF 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=+25ºC, full output load, natural air convection.
5. The On/Off Control is normally controlled by a switch. But it may also be driven with
external 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..
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. Electronic overvoltage shutdown is not included on 48V input models to comply
with certain telecom reliability requirements. These requirements attempt continued
operation despite input overvoltage. The converter is rated only to the maximum
input voltage.
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 biased 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. Use approximately twice the full input current rating with nominal
input voltage.
16. Output current limit is non-latching. When the overcurrent fault is removed, the
converter will immediately recover.
17. The Sense inputs are not included on lower current output models.
18. ULE-12/4.2-D24 minimum load is 0.42 Amps (10%) for rated specifi cations.
19. ULE-5/12-D24 IOUT=8A max. if VIN=19-20V.
20. ULE-12/4.2-D48 has no surface mount option.
21. Full load conditions, see ordering guide.
FUNCTIONAL SPECIFICATION NOTES
PHYSICAL CHARACTERISTICS AND SAFETY
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 1 ounce (28 grams)
Electromagnetic interference (external fi lter required) Designed to meet EN55022/CISPR22 with external fi lter
Safety Certifi ed to UL/cUL 60950-1, CSA-C22.2 No. 60950-1, IEC/EN 60950-1, 2nd edition
www.murata-ps.com/support
TYPICAL PERFORMANCE CURVES
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LFM
LFM
LFM
20 25 30 40 50 60 70 80
35 45 55 65 75 85
ULE-2.5/20-D24N Maximum Current Temperature Derating
VIN = 24V, transverse air flow at sea level
Output Current (Amps)
Ambient Temperature (°C)
20
19.5
19
18.5
18
17.5
17
16.5
Natural convection
100 lfm
200 lfm
300 lfm
400 lfm
ULE-2.5/20-D24N
Efficiency vs. Line Voltage and Load Current @ +25°C
2 4 6 8 10 12 14 16 18 20
Load Current (Amps)
Efficiency (%)
V
IN
= 19V
V
IN
= 24V
V
IN
= 36V
92
90
88
86
84
82
80
78
76
74
–40 0 25 35 45 55 65 75 85
30 40 50 60 70 80
ULE-1.5/20-D48 Maximum Current Temperature Derating
(VIN = 48V, air flow direction is transverse)
Output Current (Amps)
Ambient Temperature (°C)
25
20
15
10
5
0
100 lfm
400 lfm
200 lfm
300 lfm
ULE-1.5/20-D48N
Efficiency vs. Line Voltage and Load Current @ +25°C
2 4 6 8 10 12 14 16 18 20
Load Current (Amps)
Efficiency (%)
V
IN
= 36V
V
IN
= 48V
V
IN
= 75V
90
88
86
84
82
80
78
76
74
72
70
ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 6 of 26
www.murata-ps.com/support
TYPICAL PERFORMANCE CURVES
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.ATURAL#ONVECTION
LFM
ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 7 of 26
www.murata-ps.com/support
TYPICAL PERFORMANCE CURVES
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/UTPUT#URRENT!MPS
!MBIENT4EMPERATUREo#
LFM
LFM
.ATURALCONVECTION
LFM
94
92
90
88
86
84
82
80
78
ULE-5/10-D12
Efficiency vs. Line Voltage and Load Current @ +25°C
1.2 2.4 3.6 4.8 6 7.2 8.4 9.6 10.8 12
Load Current (Amps)
Efficiency (%)
V
IN
= 9V
V
IN
= 12V
V
IN
= 18V
ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 8 of 26
www.murata-ps.com/support
TYPICAL PERFORMANCE CURVES
5,%$
%FFICIENCYVS,INE6OLTAGEAND,OAD#URRENT #
,OAD#URRENT!MPS
%FFICIENCY
6
).
6
6
).
6
6
).
6
–40 0 30 40 50 60 70 80 90 35 45 55 65 75 85
ULE-5/12-D48 Maximum Current Temperature Derating
(VIN = 48V, air flow direction from input to output)
Output Current (Amps)
Ambient Temperature ( oC)
12.5
12
11.5
11
10.5
10
9.5
9
8.5
8
100 lfm
200 lfm
300 lfm
ULE-12/4.2-D24
Efficiency Vs. Line Voltage and Load Current @25ºC
Efficiency (%)
Load Current (Amps)
94
92
90
88
86
84
82
80
78
76
V
IN
= 18V
V
IN
= 24V
V
IN
= 26V
0.20 0.60 1.00 1.40 1.80 2.20 2.60 3.00 3.40 3.80 4.20 20 25 30 40 50 60 70 80
35 45 55 65 75 85
ULE-12/4.2-D24N Maximum Current Temperature Derating
(VIN=24V, transverse airflow at sea level)
Output Current (Amps)
Ambient Temperature (°C)
4.2
4.1
4.0
3.9
3.8
3.7
3.6
3.5
3.4
3.3
3.2
Natural convection
100 lfm
200 lfm
300 lfm
400 lfm
90
5,%$
%FFICIENCYVS,INE6OLTAGEAND,OAD#URRENT #
,OAD#URRENT!MPS
%FFICIENCY
6
).
6
6
).
6
6
).
6
20 25 30 40 50 60 70 80
35 45 55 65 75 85
ULE-12/4.2-D48N Maximum Current Temperature Derating
(VIN=48V, transverse airflow at sea level)
Output Current (Amps)
Ambient Temperature (°C)
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
Natural convection
100 lfm
200 lfm
300 lfm
400 lfm
90
ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 9 of 26
www.murata-ps.com/support
TYPICAL PERFORMANCE CURVES
5,%$0OWER$ISSIPATIONVS,OAD#URRENT #
,OAD#URRENT!MPS
0OWER$ISSIPATION7ATTS
6
).
6
6
).
6
6
).
6
5,%$0OWER$ISSIPATIONVS,OAD#URRENT #
,OAD#URRENT!MPS
0OWER$ISSIPATION7ATTS
6
).
6
6
).
6
6
).
6
5,%$0OWER$ISSIPATIONVS,OAD#URRENT #
,OAD#URRENT!MPS
0OWER$ISSIPATION7ATTS
6
).
6
6
).
6
6
).
6
5,%$0OWER$ISSIPATIONVS,OAD#URRENT #
,OAD#URRENT!MPS
0OWER$ISSIPATION7ATTS
6
).
6
6
).
6
6
).
6
70
72
74
76
78
80
82
84
86
88
90
92
0.10 0.22 0.33 0.45 0.56 0.68 0.79 0.91 1.02 1.14 1.2
5
ULE-48/1.25-D48
Efficiency vs. Line Voltage and Load Current @ +25°C
Load Current (Amps)
Efficiency (%)
VIN = 60V
VIN = 48V
VIN = 36V
VIN = 75V
ULE-24/3-D48
Efficiency vs. Line Voltage and Load Current @ +25°C
Load Current (Amps)
Efficiency (%)
84
85
86
87
88
89
90
91
92
93
0.3 0.65 1 1.3 1.65 2 2.3 2.65 3
VIN = 60V
VIN = 48V
VIN = 36V
VIN = 75V
ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 10 of 26
www.murata-ps.com/support
TYPICAL PERFORMANCE CURVES
5,%$0OWER$ISSIPATIONVS,OAD#URRENT #
,OAD#URRENT!MPS
0OWER$ISSIPATION7ATTS
6
).
6
6
).
6
6
).
6
5,%$0OWER$ISSIPATIONVS,OAD#URRENT #
,OAD#URRENT!MPS
0OWER$ISSIPATION7ATTS
6
).
6
6
).
6
6
).
6
5,%$0OWER$ISSIPATIONVS,OAD#URRENT #
,OAD#URRENT!MPS
0OWER$ISSIPATION7ATTS
6
).
6
6
).
6
6
).
6
5,%$0OWER$ISSIPATIONVS,OAD#URRENT #
,OAD#URRENT!MPS
0OWER$ISSIPATION7ATTS
6
).
6
6
).
6
6
).
6
ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 11 of 26
www.murata-ps.com/support
TYPICAL PERFORMANCE CURVES
5,%$0OWER$ISSIPATIONVS,OAD#URRENT #
,OAD#URRENT!MPS
0OWER$ISSIPATION7ATTS
6
).
6
6
).
6
6
).
6
1
2
3
4
5
6
7
0.1 0.2 0.3 0.4 0.6 0.7 0.8 0.9 1.0 1.1 1.
3
ULE-48/1.25-D48 Power Dissipation vs. Load Current @ +25°C
Load Current (Amps)
Power Dissipation (Watts)
V
IN
= 75V
V
IN
= 60V
V
IN
= 48V
V
IN
= 36V
ULE-24/3-D48 Power Dissipation vs. Load Current @ +25°C
Load Current (Amps)
Power Dissipation (Watts)
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
6.5
0.3 0.65 1 1.3 1.65 2 2.3 2.65 3
V
IN
= 75V
V
IN
= 60V
V
IN
= 48V
V
IN
= 36V
0 20 40 60 80 100 120
1.25
1.0
0.75
0.5
0.25
0
Output Current (Amps)
Ambient Temperature (°C)
Natural convection
100 lfm
ULE-48/1.25-D48 Maximum Current Temperature Derating at sea level
ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 12 of 26
www.murata-ps.com/support
MECHANICAL SPECIFICATIONS
–V
IN
+V
IN
OPTO
ISOLATION
PWM
CONTROLLER
REFERENCE &
ERROR AMP
UV, OV AND
OVER-TEMPERATURE
COMPARATORS
ON/OFF
CONTROL
+SENSE
−SENSE
+V
OUT
−V
OUT
GATE
DRIVE
FEEDBACK
TRIM
ULE-3.3/20-D48N
Typical topology is shown.
–V
IN
+V
IN
PWM
CONTROLLER
REFERENCE &
ERROR AMP
UV, OV AND
OVER-TEMPERATURE
COMPARATORS
ON/OFF
CONTROL
+V
OUT
−V
OUT
FEEDBACK
ULE-12/4.2-D48N
Typical topology is shown.
The ULE series consist of a number of unique high performance designs
sharing similar mechanical outlines and pinouts. The internal architecture
uses several different topologies including push-pull, fl yback and others.
The block diagrams below are typical examples and are not intended to be
exact representations. Some models do not include Sense and Trim pins. Please
be aware that Murata Power Solutions may change these designs as needed.
ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 13 of 26
www.murata-ps.com/support
MECHANICAL SPECIFICATIONS
–V
IN
+V
IN
OPTO
ISOLATION
PWM
CONTROLLER
REFERENCE &
ERROR AMP
UV, OV AND
OVER-TEMPERATURE
COMPARATORS
ON/OFF
CONTROL
+V
OUT
−V
OUT
FEEDBACK
TRIM
ULE-24/2-D48N
Typical topology is shown.
ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 14 of 26
www.murata-ps.com/support
Pin shoulder, 0.072 ±0.002 dia. (1.83 ±0.05)
0.040 (1.02) dia. pin
Pin depth, see table
Keep-out area
Seating plane
User’s host
PC Board
ULE Converter
Drawing not to scaleDimensions are in inches (mm)
ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 15 of 26
MECHANICAL SPECIFICATIONS
Through-hole Pin Changes for 2008
In 2008, for through-hole models only, Murata Power Solutions will gradually
phase over to a different extruded 0.040” (1.02 mm) diameter pin design and
elimination of the spacer standoffs on most models. This will have no effect on
installation, interchangeability, electrical or mechanical specifi cations. Any
machined 0.062” (1.57 mm) diameter pin will transition to a straight wire 0.062”
pin. The new 0.040” pins will insert properly to existing host PC boards and
include an integral pin shoulder to form the mounting plane (Figure 1). There is
no model number change, only a slightly changed appearance. Use the drawings
and table below to identify the new pin design. And, surface mount ULEs are not
affected.
All new production models are RoHS-6 compliant and always use the –C
model number suffi x. Older non-RoHS models are also being changed over to
the new extruded pins; however non-RoHS models are not listed in this table.
Extruded 0.040-inch Pin Confi gurations
RoHS Models (-C) 0.040" Pin depth*
ULE-1.5/20-D24P-C 0.25 (6.4)
ULE-1.5/20-D48-C 0.25 (6.4)
ULE-1.8/20-D24-C 0.25 (6.4)
ULE-1.8/20-D48-C 0.25 (6.4)
ULE-2.5/20-D24-C 0.19 (4.8)
ULE-2.5/20-D48-C 0.19 (4.8)
ULE-3.3/20-D12-C 0.19 (4.8)
ULE-3.3/20-D24-C 0.25 (6.4)
ULE-3.3/20-D48N-C 0.25 (6.4)
ULE-3.3/20-D48P-C 0.19 (4.8)
ULE-5/10-D12-C 0.19 (4.8)
ULE-5/12-D24-C 0.19 (4.8)
ULE-5/12-D48-C 0.25 (6.4)
ULE-12/4.2-D24-C 0.25 (6.4)
ULE-12/4.2-D48-C 0.25 (6.4)
ULE-24/3-D48N-C 0.25 (6.4)
ULE-48/1.25-D48-C 0.25 (6.4)
*The “0.040-inch pin depth” is the distance between the mounting plane of the ULE
converter (at the pin shoulder) and the inserted tip of the pin. Therefore it is the length of
pin which the host receiving PC board must accept. The ULE mounting plane interfaces
to the top mounting surface (seating plane) of the user’s PC board. The ULE mounting
plane is established either by an integral pin shoulder (new) or a plastic standoff (older)
but not both. Users should avoid placing components immediately below the converter.
The pin fi nish for all models remains as gold plate over nickel underplate.
The pin material is a copper alloy. The pin fi nish is suitable for both leaded
and lead-free solders.
Figure 1. Extruded 0.040-inch Pin
The “integral” pin shoulder is formed as part of the extruded pin fabrica-
tion and replaces the plastic standoff spacer. The shoulder diameter is 0.072
+/−0.002" and forms the mounting plane of the converter. The user should
provide suffi cient clearance for a 0.040" pin hole but well below the 0.072"
shoulder diameter. This mounting plane avoids mechanical stress placed on
the converter components. Do not place the components below the converter.
Dimensions in inches (mm)
ULE Connections
The ULE series consists of several different PC board layouts sharing a
common outline specifi
cation and overall size. This simplifi es interchange-
ability in case the user needs different input or output specifi cations.
Certain models do not include Sense or Trim connections. All models
include Remote On/Off control pins. Please refer to the following table:
Model Number Vout
(Volts)
Iout
(Amps,
max.)
Number
of Pins
On/Off
pin?
Trim
pin?
Sense
pins?
ULE-1.5/20-D24P-C 1.5 20 8 yes yes yes
ULE-1.5/20-D48N-C 1.5 20 8 yes yes yes
ULE-1.8/20-D24P-C 1.8 20 8 yes yes yes
ULE-1.8/20-D48N-C 1.8 20 8 yes yes yes
ULE-2.5/20-D24P-C 2.5 20 8 yes yes yes
ULE-2.5/20-D48N-C 2.5 20 8 yes yes yes
ULE-3.3/20-D12P-C 3.3 20 8 yes yes yes
ULE-3.3/20-D24P-C 3.3 20 8 yes yes yes
ULE-3.3/20-D48N-C 3.3 20 8 yes yes yes
ULE-5/10-D12P-C 5 10 8 yes yes yes
ULE-5/12-D24P-C 5 12 8 yes yes yes
ULE-5/12-D48N-C 5 12 8 yes yes yes
ULE-12/4.2-D24P-C 12 4.2 6 yes yes no
ULE-12/4.2-D48N-C 12 4.2 6 yes yes no
ULE-24/3-D48N-C 24 3 5 yes no no
ULE-48/1.25-D48N-C 48 1.25 5 yes no no
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ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 16 of 26
MECHANICAL SPECIFICATIONS, THROUGH-HOLE (PINNED) MODELS
DOSA-Compatible
Input/Output Connections
Pin Function P32
1 −Vin*
2 On/Off Control**
3 +Vin*
4 −Vout
5 −Sense†
6 Output Trim
7 +Sense†
8 +Vout
* These converters are pin-for-pin/plug-
compatible to competitive units. Other
units may use different pin numbering or
alternate outline views. When laying out
your PC board, follow the pin FUNCTION.
DOSA designates Pin 1 as +Input and Pin
3 as -Input.
** The Remote On/Off can be provided
with either positive (P suffi x) or negative
(N suffi x) polarity.
† Sense Pins omitted if function is not used
THIRD ANGLE PROJECTION
4.78
0.188
See
Table
0.071±.002 SHOULDER
AT PINS 1-3, 5-7
1.80±0.05
PLATED THRU HOLES
TYP±.010.061
58.4
2.30
50.80
2.000 3.81
0.150
22.9
0.90 11.4
0.45
7.62
0.300
0.300
7.62
3.81
0.150
0.150
3.81
0.083±0.010
PLATED THRU HOLES
2x (Pins 4 & 8)
MOUNTING PLANE
SIDE VIEW
0.040±0.002
PINS 1-3, 5-7
1.02±0.05
0.062±0.002
PINS 4 & 8
1.57±0.05
DIMENSIONS ARE IN INCHES [mm]
TOLERANCES:
2 PLACE 0.02 ANGLES: 1
3 PLACE 0.010
COMPONENTS SHOWN ARE FOR REFERENCE ONLY
MATERIAL:
SMT PINS: COPPER ALLOY
FINISH: (ALL PINS)
GOLD (5u"MIN) OVER NICKEL (50u" MIN)
BOTTOM VIEW
PIN 3
PIN 2
PIN 1
PIN 6
PIN 8
PIN 4
PIN 5†
PIN 7†
2.22
56.4
0.89
22.6 0.300
7.62
0.300
7.62
2.000
50.80 0.150
3.81
0.150
3.81
0.300
7.62
0.300
7.62
ISOMETRIC VIEW
RECOMMENDED FOOTPRINT
(VIEW THROUGH CONVERTER)
3
2
1
8
6
4
5†
7†
C
L
C
L
END VIEW
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ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 17 of 26
MECHANICAL SPECIFICATIONS, SURFACE-MOUNT (GULLWING) MODELS
THIRD ANGLE PROJECTION
Table
See 0.025
0.63
0.150
7.62
59.44
2.340
4.64
0.183 4.64
0.183
58.4
2.30
22.9
0.90
7.62
0.300
0.300 0.300
7.62
3.30
0.130 3.81
0.150
3.81
7.62
0.300
0.020
0.51
0.300
7.62
7.62
0.300
0.300
7.62
3.81
0.150
3.81
0.150
0.300
7.62
PINS COPLANAR WITHIN 0.004"
SIDE VIEW
RECOMMENDED FOOTPRINT
(VIEW THROUGH CONVERTER)
C
L
8
7**
6
5**
4
3
2
1
BOTTOM VIEW
PIN 1
PIN 2
PIN 3 PIN 6
PIN 7**
PIN 8
PIN 5**
PIN 4
0.89
22.6
0.125 TYP
2.30
58.4
DIMENSIONS ARE IN INCHES [mm]
TOLERANCES:
2 PLACE 0.02 ANGLES: 1
3 PLACE 0.010
COMPONENTS SHOWN ARE FOR REFERENCE ONLY
MATERIAL:
SMT PINS: COPPER ALLOY
FINISH: (ALL PINS)
PURE TIN (100u"MIN) OVER NICKEL (75u" MIN)
ISOMETRIC VIEW
C
L
END VIEW
Input/Output Connections
Pin Function P32
1 −Vin
2 On/Off Control*
3 +Vin
4 −Vout
5 −Sense**
6 Output Trim
7 +Sense**
8 +Vout
* The Remote On/Off can be provided
with either positive (P suffi x) or negative
(N suffi x) polarity.
** Sense Pins omitted if function is not used
Please refer to the “ULE Connections” table.
www.murata-ps.com/support
ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 18 of 26
Table
See
Table
See
0.122 REF OR 0.150 REF*
NOMINAL
DEPENDING ON MODEL
TYPE 'M' GULL WING SMT PACKAGE
0.130 REF
DIMENSIONS ARE IN INCHES [mm]
TOLERANCES:
2 PLACE 0.02 ANGLES: 1
3 PLACE 0.010
COMPONENTS SHOWN ARE FOR REFERENCE ONLY
THRU-HOLE STANDARD PACKAGE
MECHANICAL SPECIFICATIONS, Continued
ULE THRU-HOLE SERIES MAXIMUM HEIGHTS
Model Family Height (Max) Model Family Height (Max)
ULE-1.5/20-D24 0.404 [10.26] *ULE-5/12-D24 0.405 [10.29]
ULE-1.5/20-D48 0.381 [9.68] ULE-5/12-D48 0.377 [9.58]
ULE-1.8/20-D24 0.404 [10.26] ULE-12/4.2-D24 0.377 [9.58]
ULE-1.8/20-D48 0.381 [9.68] ULE-12/4.2-D48 0.377 [9.58]
ULE-2.5/20-D24* 0.409 [10.39] ULE-24/3-D48 0.425 [10.80]
ULE-2.5/20-D48* 0.409 [10.39] ULE-48/1.25-D48 0.448 [11.38]
ULE-3.3/20-D12* 0.409 [10.39] ULE-68/1.5-D48 0.377 [9.58]
ULE-3.3/20-D24 0.381 [9.68]
ULE-3.3/20-D48* 0.409 [10.39]
ULE 'M' TYPE SMT (GULL WING) SERIES MAXIMUM HEIGHTS
Model Family Height (Max) Model Family Height (Max)
ULE-1.5/20-D24 M 0.404 [10.26] ULE-5/10-D12 M 0.400 [10.16]
ULE-1.5/20-D48 M 0.404 [10.26] ULE-5/12-D24 M 0.400 [10.16]
ULE-1.8/20-D24 M 0.404 [10.26] ULE-5/12-D48 M 0.400 [10.16]
ULE-1.8/20-D48 M 0.404 [10.26] ULE-12/4.2-D24 M 0.400 [10.16]
ULE-2.5/20-D24 M 0.404 [10.26] ULE-48/1.25-D48 M 0.446 [11.33]
ULE-3.3/20-D12 M 0.404 [10.26]
ULE-3.3/20-D24 M 0.404 [10.26]
ULE-3.3/20-D48 M 0.404 [10.26]
www.murata-ps.com/support
TECHNICAL NOTES
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 sustained, non-current-limited, input-voltage polarity
reversals exist. For Murata Power Solutions ULE 24-60 Watt DC/DC Converters,
you should use fast-blow type fuses, installed in the ungrounded input supply
line, with values no greater than the following.
Model Fuse Values
12 Volt Input 10 Amps
24 Volt input 5 Amps
48 Volt Input 4 Amps
All relevant national and international safety standards and regulations must
be observed by the installer. For system safety agency approvals, the convert-
ers must be installed in compliance with the requirements of the end-use
safety standard.
Input Undervoltage Shutdown and Start-Up Threshold
Under normal start-up conditions, devices will not begin to regulate until
the ramping-up input voltage exceeds the Start-Up Threshold Voltage. Once
operating, devices will not turn off until the input voltage drops below the
Undervoltage Shutdown limit. Subsequent re-start will not occur until the input
is brought back up to the Start-Up Threshold. This built in hysteresis prevents
any unstable on/off situations from occurring at a single input voltage.
Start-Up Time
The VIN to VOUT Start-Up Time is the interval of time between the point at which
the ramping input voltage crosses the Start-Up Threshold and the fully loaded
output voltage enters and remains within its specifi ed accuracy band. Actual
measured times will vary with input source impedance, external input/output
capacitance, and load. The ULE Series implements a soft start circuit that limits
the duty cycle of its PWM controller at power up, thereby limiting the input
inrush current.
The On/Off Control to VOUT start-up time assumes the converter has its
nominal input voltage applied but is turned off via the On/Off Control pin. The
specifi cation defi nes the interval between the point at which the converter is
turned on and the fully loaded output voltage enters and remains within its
specifi ed accuracy band. Similar to the VIN to VOUT start-up, the On/Off Control
to VOUT start-up time is also governed by the internal soft start circuitry and
external load capacitance.
The difference in start up time from VIN to VOUT and from On/Off Control to
VOUT is therefore insignifi cant.
Input Source Impedance
ULE converters must be driven from a low ac-impedance input source. The
DC/DC’s performance and stability can be compromised by the use of highly
inductive source impedances. The input circuit shown in Figure 2 is a practical
solution that can be used to minimize the effects of inductance in the input
traces. For optimum performance, components should be mounted close to
the DC/DC converter. If the application has a high source impedance, low VIN
models can benefi t of increased external input capacitance.
I/O Filtering, Input Ripple Current, and Output Noise
All models in the ULE 24-60 Watt DC/DC Converters are tested/specifi ed for
input refl
ected ripple current and output noise using the specifi ed external input/
output components/circuits and layout as shown in the following two fi gures.
External input capacitors (CIN in Figure 2) serve primarily as energy-storage
elements, minimizing line voltage variations caused by transient IR drops in
conductors from backplane to the DC/DC. Input caps should be selected for bulk
capacitance (at appropriate frequencies), low ESR, and high rms-ripple-current
ratings. The switching nature of DC/DC converters requires that dc voltage
sources have low ac impedance as highly inductive source impedance can affect
system stability. In Figure 2, CBUS and LBUS simulate a typical dc voltage bus. Your
specifi c system confi guration may necessitate additional considerations.
CINVIN CBUS
LBUS
CIN = 33µF, ESR < 700mΩ @ 100kHz
CBUS = 220µF, ESR < 100mΩ @ 100kHz
LBUS = 12µH
+VIN
–VIN
CURRENT
PROBE
TO
OSCILLOSCOPE
+
–
Figure 2. Measuring Input Ripple Current
ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 19 of 26
www.murata-ps.com/support
In critical applications, output ripple/noise (also referred to as periodic and
random deviations or PARD) may be reduced below specifi ed limits using fi lter-
ing techniques, the simplest of which is the installation of additional external
output capacitors. These output caps function as true fi lter elements and
should be selected for bulk capacitance, low ESR and appropriate frequency
response. All external capacitors should have appropriate voltage ratings and
be located as close to the converter as possible. Temperature variations for all
relevant parameters should also be taken carefully into consideration. The most
effective combination of external I/O capacitors will be a function of line volt-
age and source impedance, as well as particular load and layout conditions.
In Figure 3, the two copper strips simulate real-world pcb impedances
between the power supply and its load. In order to minimize measurement
errors, scope measurements should be made using BNC connectors, or the
probe ground should be less than ½ inch and soldered directly to the fi xture.
rise above the designed operating temperature, 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. See Performance/
Functional Specifi cations.
Output Overvoltage Protection
ULE output voltages are monitored for an overvoltage condition via magnetic
feedback. The signal is coupled to the primary side and if the output voltage
rises to a level which could be damaging to the load, the sensing circuitry will
power down the PWM controller causing the output voltages to decrease. Fol-
lowing a time-out period the PWM will restart, causing the output voltages to
ramp to their appropriate values. If the fault condition persists, 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.
Contact Murata Power Solutions for an optional output overvoltage monitor
circuit using a comparator which is optically coupled to the primary side thus
allowing tighter and more precise control.
Current Limiting
As soon as the output current increases to 10% to 50% above its rated value,
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 somewhat constant power dissipation. This is commonly
referred to as power limiting. Current limit inception is defi ned as the point at
which the full-power output voltage falls below the specifi ed tolerance. See
Performance/Functional Specifi cations. If the load current, being drawn from
the converter, is signifi cant enough, the unit will go into a short circuit condition
as specifi ed under "Performance."
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, 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 ULE is capable of enduring an
indefi nite short circuit output condition.
Features and Options
On/Off Control
The input-side, remote On/Off Control function can be ordered to operate with
either polarity:
Standard models are equipped with Positive-polarity (“P" part-number
suffi x) and these devices are enabled when the On/Off Control is left open or
is pulled high, as per Figure 4. Positive-polarity devices are disabled when the
On/Off Control is pulled low.
Figure 3. Measuring Output Ripple/Noise (PARD)
Floating Outputs
Since these are isolated DC/DC converters, their outputs are "fl oating" with
respect to their input. Designers will normally use the –Output (pin 4) as the
ground/return of the load circuit. You can, however, use the +Output (pin 8) as
ground/return to effectively reverse the output polarity.
Minimum Output Loading Requirements
ULE converters employ a synchronous-rectifi er design topology and all models
regulate within spec and are stable under no-load to full load conditions.
Operation under no-load conditions however might slightly increase the output
ripple and noise.
Thermal Shutdown
These ULE converters are equipped with thermal-shutdown circuitry. If envi-
ronmental conditions cause the internal temperature of the DC/DC converter to
C1
C1 = 0.47μF CERAMIC
C2 = NA
LOAD 2-3 INCHES (51-76mm) FROM MODULE
C2 R
LOAD
SCOPE
+VOUT
–VOUT
+SENSE
–SENSE
ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 20 of 26
www.murata-ps.com/support
Figure 4. Driving the Positive Polarity On/Off Control Pin
Optional Negative-polarity devices (“N” suffi x) are off when the On/Off Control
is open (or pulled high), and on when the On/Off Control is pulled low with
respect to –VIN as shown in Figure 5.
Figure 6. Trim Connections Using A Trimpot
Figure 5. Driving the Negative Polarity On/Off Control Pin
Dynamic control of the remote on/off function is facilitated with a mechanical
relay or an open-collector/open-drain drive circuit (optically isolated if appropri-
ate). The drive circuit should be able to sink appropriate current (see Performance
Specs) when activated and withstand appropriate voltage when deactivated.
Applying an external voltage to the On/Off Control when no input power is
applied to the converter can cause permanent damage to the converter.
Trimming Output Voltage
ULE converters have a trim capability that allows users to adjust the output
voltages as listed in the specifi cations. Adjustments to the output voltages can
be accomplished via a trim pot (Figure 6) or a single fi xed resistor as shown
in Figures 7 and 8. A single fi xed resistor can increase or decrease the output
voltage depending on its connection. The resistor should be located close to
the converter and have a TCR less than 100ppm/°C to minimize sensitivity
to changes in temperature. If the trim function is not used, leave the trim pin
fl oating.
Figure 7. Trim Connections To Increase Output Voltages Using a Fixed Resistor
ON/OFF CONTROL
CONTROL
+ Vcc
-VIN
Figure 8. Trim Connections To Decrease Output Voltages
A single resistor connected from the Trim to the +Output, or +Sense where
applicable, will increase the output voltage in this confi guration. A resistor con-
nected from the Trim to the –Output, or –Sense where applicable, will decrease
the output voltage in this confi guration.
Trim adjustments greater than the specifi ed range 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 adjust-
ment 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 converter's specifi ed rating or
cause output voltages to climb into the output overvoltage region. Therefore:
(VOUT at pins) x (IOUT) <= rated output power
+ VIN +VCC
–VIN
O N /O F F
C O N TR O L
1M
5-20
TURNS
LOAD
+VOUT
–VIN
+VIN
ON/OFF
CONTROL TRIM
+SENSE
–VOUT
–SENSE
LOAD
R1
+VOUT
–VIN
+VIN
ON/OFF
CONTROL TRIM
+SENSE
–VOUT
–SENSE
LOAD
R2
+VOUT
–VIN
+VIN
ON/OFF
CONTROL TRIM
+SENSE
–VOUT
–SENSE
ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 21 of 26
www.murata-ps.com/support
Note: Resistor values are in k. Adjustment accuracy is subject to resistor
tolerances and factory-adjusted output accuracy. VO = desired output voltage.
Remote Sense 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 should connect the +Sense to +VOUT and –Sense to
–VOUT at the DC/DC converter pins.
ULE series converters have 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 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 applications, twisted pair or other techniques should be implemented.
ULE series converters will compensate for drops between the output voltage
at the DC/DC and the sense voltage at the DC/DC provided that:
[VOUT(+) –VOUT(–)] –[Sense(+) –Sense (–)] 5% 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
ULE’s specifi ed rating or cause output voltages to climb into the output over-
voltage region. Also, the use of Trim Up and Sense combined may not exceed
+10% of VOUT. Therefore, the designer must ensure:
(VOUT at pins) x (IOUT) rated output power
Trim Equations
Trim Up Trim Down
UP VO– 3.3
RT (k ) = –10.2
13.3(VO– 1.226)
3.3 – VO
RT (k ) = –10.2
16.31
DOWN
3.3 Volt Output
UP VO– 5
RT (k ) = –10.2
20.4(VO– 1.226)
5– VO
RT (k ) = –10.2
25.01
DOWN
5 Volt Output
UP VO– 12
RT (k ) = –10.2
49.6(VO– 1.226)
UP VO– 15
RT (k ) = –10.2
62.9(VO– 1.226)
12 – VO
RT (k ) = –10.2
60.45
DOWN
15 – VO
RT (k ) = –10.2
76.56
DOWN
12 Volt Output
15 Volt Output
Figure 9. Remote Sense Circuit Confi guration
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
CONTROL TRIM
+SENSE
–VOUT
–SENSE
IOUT Return
IOUT
ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 22 of 26
Soldering Guidelines
Murata Power Solutions recommends the specifi cations below when installing these
converters. These specifi cations vary depending on the solder type. Exceeding these
specifi cations may cause damage to the product. Be cautious when there is high
atmospheric humidity. Your production environment may differ therefore please
thoroughly review these guidelines with your process engineers.
Reflow Solder Operations for surface-mount products (SMT)
For Sn/Ag/Cu based solders:
Preheat Temperature Less than 1 ºC. per second
Time over Liquidus 45 to 75 seconds
Maximum Peak Temperature 260 ºC.
Cooling Rate Less than 3 ºC. per second
For Sn/Pb based solders:
Preheat Temperature Less than 1 ºC. per second
Time over Liquidus 60 to 75 seconds
Maximum Peak Temperature 235 ºC.
Cooling Rate Less than 3 ºC. per second
Wave Solder Operations for through-hole mounted products (THMT)
For Sn/Ag/Cu based solders:
Maximum Preheat Temperature 115° C.
Maximum Pot Temperature 270° C.
Maximum Solder Dwell Time 7 seconds
For Sn/Pb based solders:
Maximum Preheat Temperature 105° C.
Maximum Pot Temperature 250° C.
Maximum Solder Dwell Time 6 seconds
www.murata-ps.com/support
Surface-Mount Package ("M" suffi x)
Murata Power Solutions’ ULE series SMT DC/DC converters are the only higher-
power DC/DCs that can be automatically “pick-and-placed” using standard
vacuum-pickup equipment and subsequently refl owed using high-temperature,
lead-free solder.
Virtually all SMT DC/DCs today are unprotected "open-frame" devices as-
sembled by their vendors with high-temperature solder (usually Sn96.5/Ag3.5
with a melting point +221°C) so that you may attach them to your board using
low-temperature solder (usually Sn63/Pb37 with a melting point of +183°C).
Conceptually straightforward, this "stepped" solder approach has its limita-
tions . . . and is clearly out of step with an industry trending toward the broad
use of lead-free solders. Users need to experiment and develop refl ow profi les
that ensure the components on their DC/DC never exceed 215-216°C. If those
components get too hot, "double-refl ow" could compromise the reliability of
their solder joints. Virtually all these devices demand you "cool down" the Sn63
profi le you are likely using today.
Murata Power Solutions is not exempted from the Laws of Physics. And we
do not have magic solders no one else has. We do have a simple and practical,
straightforward approach that works. We assemble our SMT DC/DCs on a
thermally-stable plastic lead-frame (nylon 46, UL94V-0 fl ammability rated) using
a high temperature lead-free solder. The lead-frame ensures coplanarity (to
within 0.004 in.) of the unit's tin-plated (150 microinches) copper leads and
also supports a removable heat shield.
The disposable heat shield, with a cutaway exposing the package leads,
provides thermal insulation to internal components during refl ow and doubles as
the vacuum pick-up location. The insulation properties of the heat shield are so
effective that temperature differentials as high as 50°C develop inside-to-outside
the shield. Oven temperature profi les with peaks of 250-260°C and dwell times
exceeding 2 minutes above 221°C are easily achieved. Murata Power Solutions’
new-generation SMT units are shipped in stackable, JEDEC-style plastic trays
(Figure 13).
Automated Assembly Production Notes
Murata Power Solutions’ new high-effi ciency DC/DC converters are designed
for modern surface-mount technology (SMT) automated assembly using
screened solder paste, "pick and place" component positioning and forced
hot air refl ow oven soldering. If you are new to SMT techniques and have a
volume application, these features save time, cost and improve manufacturing
effi ciency. Murata Power Solutions’ DC/DC assembly operations themselves
make extensive use of such techniques.
Even if you have previous SMT experience, you should read the sections be-
low on solder refl ow profi les and heat shields. This information is not intended
to replace the documentation for your SMT system. We assume that you are
already experienced with all the components of your SMT system.
This section will discuss several SMT issues, including:
I/O Mechanical Confi guration
Part Handling and Supply
Printed Circuit Board (pcb) Mounting
Soldering using Refl ow Technology
Temperature Profi ling
Heat Shields and Removal
Mechanical Confi guration of Input/Output Connections
These new converters are supplied either using traditional through-hole pins
or SMT leads. (Note that some models are offered only with lead mounting).
The pin options insert into plated-through holes in the host pcb. Be aware that
some heat dissipation is carried off by either the pins or leads. The Derating
Curves assume that some additional pad area is available on your host pcb to
absorb the heat.
The lead option uses either short tabs in "gullwing" style or standoff leads
under the converter. The gullwing leads typically are copper alloy with 150
microinches of tin plating. Solder paste (typically 0.008" to 0.009" thick) is ap-
plied to the host pcb using a solder mask pressure screening technique and the
board is heated and cooled long enough for the solder to refl ow and adhere to
both the host pads and the converter’s mounting leads.
After such mounting, the entire mechanical mounting load is carried by the
solder. Obviously the converters must be accurately positioned all during the
solder refl ow period. Where solder surface tension is suffi cient to force tiny
components into position, these larger converters may not move and must be
accurately positioned by your SMT system.
Part Handling and Supply
SMT eighth- and quarter-brick DC/DC converters (plus installed heat shields if
used) are supplied in JEDEC-standard 5.35" by 12.4" waffl
e trays which are
compatible with the feeders on industry-standard pick-and-place machines.
Since the converters are larger and heavier than many other components,
make sure your system can reliably remove the units from their trays, move
them to the host pcb and accurately position them. The plastic heat shield
(Figure 10) doubles as a vacuum pickup area.
Figure 10. ULE SMT DC/DC with Disposable Heat Shield
Solder Balls
ULE converters are thoroughly inspected according to military standard
J-STD-001B for the presence of solder balls. The specifi cation allows small
solder balls as long as they are rigidly attached and do not compromise the
spacing and clearance requirements needed to maintain electrical isolation.
ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 23 of 26
www.murata-ps.com/support
0.150 TYP.
(3.81)
2.340 (59.44)
0.020 (0.51)
1.975 (50.17)
SMT UNIT
PCB
SMT LEAD
Copper Pad
0.183
(4.65)
0.020 REF.
(0.51)
0.130 TYP.
(3.30)
DIMENSIONS ARE IN INCHES (MM)
0.300 TYP.
(7.62)
Orientation: When loaded into JEDEC trays, the converters
are oriented in the same direction. See the diagram below. For
the ULE series, a notch is placed on the top of the case (on the
removal tabs) to indicate the pin 1 position. You should visually
inspect the tray to be sure of this orientation.
Most pick-and-place automatic assembly systems use a
camera which must be trained to recognize the orientation of
the converter before it is assembled onto the host PC board.
This “training” locates and identifi es prominent, dimensionally
stable landmarks such as the board corners or fi ducial marks.
On the bottom of the converter, the ULE series include optical fi ducial marks
viewable by your SMT imaging system. Observing from the bottom, your SMT
imaging camera should fi nd these marks to identify the converter and verify pin
1. On most pick-and-place systems, during head transit, the imaging system will
automatically fi ne tune the end mounting position of the converter using image
comparisons from these fi ducials or other reference marks you have chosen.
The fi ducial marks are placed fairly close together because many imaging
systems have a one inch or less observing area since most SMT parts are con-
siderably smaller than these converters. You may prefer to train your imaging
system to use a corner of the converter or an I/O lead.
The fi ducial marks will remain identical within any date code lot of converters.
In the remote possibility that the fi ducials may have changed position with a PC
board revision, you should not mix different date lots on any one production as-
sembly session. In addition, to avoid non-recognition or misplacement of the con-
verter, retrain your imaging system at the beginning of each series of assembly
sessions. There may be tiny variations in the absolute position from unit to unit.
If you use a camera above the pcb after placement on the solder paste, do
not rely on the inkjet marking on the heat shield to verify proper orientation.
Use the pin 1 notch instead.
Coplanarity: Murata Power Solutions manufactures these converters with
very fl at mounting leads (see coplanarity specs) however your host pcb must
also be fl at for a successful mounting. Be aware of possible warping of the pcb
under heat gradients and/or humidity conditions. The solder paste will tolerate
a small amount of mismatch and will tend to “wet” the entire pad area by
capillary action if the temperatures are correct.
Vacuum Pickup: Select the vacuum collet on your SMT placement system
for the weight and size of the DC/DC converter. Note that units with heatsinks
are slightly heavier. Tests at Murata Power Solutions have shown that excellent
acceleration and transit head speed are available for these converters if the
collet size is proper and the vacuum is suffi cient. When positioning the vacuum
collet, use the geometric center of the heat shield as the pickup area since the
center of gravity is very close.
Soldering
Refl ow technology works well for small parts. However, larger components
such as these DC/DC’s with higher thermal mass may require additional refl ow
time (but not enough to disturb smaller parts also being refl owed concurrently
with the DC/DC). When this is combined with higher temperature lead-free sol-
ders (or solders with reduced heavy metals), there is increased risk of reheat-
ing components inside the DC/DC enough so that they either change positions
(and possibly stop functioning) or the components are damaged by the heat.
Figure 11. Recommended Solder Profi le
(When the Heat-shield temperature exceeds +250°C,
the air within is 50°C cooler)
Post Refl ow Procedures
After successful solder refl ow, be sure to completely clean and dry your assem-
bled boards using a recommended wash solution and dryer. Failure to remove all
fl ux may cause long term deterioration of on-board conductors and components.
And, traces of contaminants which are not removed may reduce isolation volt-
ages or risk a safety hazard. Be aware that low remaining concentrations of fl ux
or other assembly compounds can be very diffi cult to detect by eye.
Pick and Place pcb Mounting
The main issues here are pad area, orientation, positioning accuracy, vacuum
pickup and coplanarity. Murata Power Solutions recommends that pcb pads to
interface with the DC/DC converter should be sized as shown in the diagram
below. The pads footprint accommodates the positioning accuracy of your SMT
equipment and manufactured tolerances of the DC/DC mounting leads.
Z1 Z2 Z3 Z4 Z5 Z6 Z7
100
Seconds
Degrees Celsius
250
200
150
100
50
200 300 400 500 600
Heat Shield
Test Board
Air Under Shield
Figure 12. Recommended SMT Mounting Pad Dimensions
ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 24 of 26
www.murata-ps.com/support
5.35 (135.89)
12.40
(314.96)
2.875
(73.03)
2.875
(73.03)
2.875
(73.03)
1.032
(26.21)
1.50
(38.1)
1.50
(38.1)
PIN 1
DIMPLE
DIMENSIONS ARE IN INCHES (MM)
For these reasons, Murata Power Solutions developed disposable heat
shields using high temperature plastic. The DC/DC is installed and refl owed
with the shield in place. After successful refl ow and cooling, and before wash-
ing, the heat shield should be removed.
Temperature Profi ling
We wish to ramp the temperature up and down to successfully refl ow the
solder without heat damage. Each refl ow oven, humidity conditions, solder
paste type, oven feed rate, and the number of heat zones all require a different
profi le. Therefore you may have to experiment.
Since these converters are constructed using high temperature solders,
there will be no heat problems on your host pcb using traditional solder with
63% lead and 37% tin with a melting point of +183°C. Device lead tempera-
ture must remain below 230°C for less than 75 seconds, assuming that the
heat shield is in place. Murata Power Solutions uses a 216°C melt lead-free
tin/silver/copper alloy to assemble these converters.
There are several lead-free solders suitable for your host pcb depending on
your SMT system and whatever local certifi cation and environmental regula-
tions you must observe. Contact Murata Power Solutions if you need specifi c
advice.
Heat Shield
Careful thermocouple testing has shown that the interior of the DC/DC under
the heat shield is tens of degrees cooler than the outside ambient temperature
for typical refl ow profi les. This protects internal components and limits the
amount of refl ow where it is not desired. The heat shield also includes marking
for product identifi cation and a date/lot code.
On ULE models, the heat shield is attached to the converter using molded
plastic pins on the heat shield interior which insert into recessed dimples in
the pinframe. An extra molded pin on the heat shield at the pin 1 location (and
corresponding notch on the pcb) can only be installed one way properly on the
pinframe. If the shield accidentally comes loose, it may be reinstalled by align-
ing the pins and dimples.
To remove the shield from the converter, after successful mounting and cool-
ing, squeeze the heat shield ears inward toward the converter body and pull the
shield upwards. Discard or recycle the shield. If you are using a fl ux wash cycle,
remove the heat shield before washing to avoid coming loose inside the washer.
Figure 13. Shipping Tray
ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 25 of 26
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
notice. © 2012 Murata Power Solutions, Inc.
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 14. 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 host carrier board for realistic heat
absorption and spreading. Both longitudinal and transverse
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.
ULE Series
Isolated, High Density, Eighth-Brick
1.25–20 Amp, DC/DC Converters
MDC_ULE Series.E05 Page 26 of 26
