ULE Models
Performance/Functional Specifications
Typical @ TA = +25°C under nominal line voltage and full-load conditions, unless noted. ➀
3
Input
Input Voltage Range:
D12 Models 10-18 Volts (12V nominal)
D24 Models 18-36 Volts (24V nominal)
D48 Models 36-75 Volts (48V nominal)
Start-Up Threshold:
D12 Models 9-10 Volts (9.6V typical)
D24 Models 18-20 Volts (19V typical)
D48 Models 31-36 Volts (35V typical)
Undervoltage Shutdown:
D12 Models 8.5-9.5 Volts (9V typical)
D24 Models 16.5-18.5 Volts (17.5V typical)
D48 Models 32.5-34.5 Volts (33.5V typical)
Input Current:
Normal Operating Conditions See Ordering Guide
Standby Mode (Off, Under Voltage) 1-8mA (model dependent)
Output Short-Circuit Condition 40-250mA (model dependent)
Low Line Voltage (VIN = VMIN):
ULE-1.8/20-D48 1.08 Amps
ULE-2.5/20-D48 1.50 Amps
ULE-3.3/20-D48 2.05 Amps
ULE-5/12-D24 3.31 Amps
ULE-5/12-D48 1.82 Amps
Input Reflected Ripple Current ➁ 15-25mAp-p (model dependent)
Input Filter Type LC type
Overvoltage Protection None
Reverse-Polarity Protection ➇ 5A max., 10sec max. via external fuse
No-load Input Current 16-90mA (model dependent)
Remote On/Off Control: ➄
Positive Logic ("P" suffix models) OFF = ground pin or +0.8 V max.
ON = open pin or +VIN max.
Negative Logic ("N" suffix models) ON = ground pin or +0.8 V max.
OFF = open pin or +VIN max.
Remote Control On/Off Current 1mA pulldown
Sense Input Range +10% of VOUT
Output
Total Output Power (VOUT x IOUT must not exceed maximum power): ➆
ULE-1.8/20-D48 36.36 Watts
ULE-2.5/12-D48 50.50 Watts
ULE-3.3/20-D48 66.83 Watts
ULE-5/12-D24 60.60 Watts
ULE-5/12-D48 60.75 Watts
Voltage Output Accuracy (50% load):
Initial ±1.25% (except ±1.5% 1.8V)
Temperature Coefficient 0.02% of VOUT per °C
Minimum Loading ➀ No minimum load
Ripple/Noise (20MHz bandwidth) See Ordering Guide
Line/Load Regulation See Ordering Guide
Efficiency See Ordering Guide
VOUT Trim Range –15% to +10%
Isolation Voltage, input/ouput:
D12 and D24 models 1500 Vdc min.
D48 models 2250 Vdc min.
Isolation Safety Rating Basic
Isolation Resistance 100MΩ
Isolation Capacitance 470-1750pF (model dependent)
Current Limit Inception (98% of VOUT):
ULE-5/12-D24 16A (cold start), 15A (warmed up)
ULE-5/12-D48 18A (cold start), 16A (warmed up)
20 Amp models 26A (cold start), 24A (warmed up)
Short Circuit Detection See Note 6
Short Circuit Protection Method Hiccup with autorecovery, See Tech Notes
Short Circuit Current 2-5 Amps (model dependent)
Short Circuit Duration Continuous, output shorted to ground
Overvoltage Protection: Method: magnetic feedback
ULE-1.8/20-D48 3Vdc
ULE-2.5/20-D48 3Vdc
ULE-3.3/20-D48 3.96Vdc
ULE-5/12-D24 6Vdc
ULE-5/12-D48 6.4Vdc
Capacitive Load 10,000µF typical
(ESR = 0.02Ω maximum) 15,000µF maximum
Dynamic Characteristics
Dynamic Load Response:
(50-75-50% load step to ±2% of VOUT) 200-250µSec, model dependent.
Start-Up Time:
On/Off or VIN on to VOUT 90mSec for VOUT = nominal
Switching Frequency:
ULE-1.8/20-D48 340kHz ±10%
ULE-2.5/20-D48 400kHz ±10%
ULE-3.3/20-D48 365kHz ±10%
ULE-5/12-D24 485kHz ±10%
ULE-5/12-D48 450kHz ±10%
Environmental
Calculated MTBF ➃ TBD Hours
Operating Temperature Range (Ambient)
No derating, natural convection
(50-100 lfm self-cooling) +60 to +75°C, model dependent, see
derating curves
With derating See derating curves
Storage Temperature Range –40 to +125°C
Thermal Protection/Shutdown 120°C
Altitude 0 to 10,000 feet
Relative Humidity 10% to 90%, non-condensing
Physical
Outline Dimensions See Mechanical Specifications
Pin Material (Through-hole model) Round copper with tin-lead plate
over nickel underplate
Weight TBD ounces
Flammability Rating UL94V-0
Electromagnetic Interference FCC Part 15, EN55022, (conducted or
radiated) Class B
Safety UL/cUL 60950 CSA-C22.2 No.234
IEC/EN 60950
➀ All models are tested and specified with external 22µF tantalum input capacitor and 10µF/
1µF tantalum/ceramic output capacitors. These capacitors are necessary to accommodate our
test equipment and may not be required to achieve specified performance in your applications.
All models are stable and regulate within spec under no-load conditions. Standard airflow is
300 lfm for extended operation.
➁ Input Ripple Current is tested and specified over a 5-20MHz bandwidth. Input filtering is
CIN = 33µF, CBUS = 220µF, LBUS = 12µH.
➂ Current limit inception is given at either cold start-up or after warm-up.
➃ Mean Time Before Failure is calculated using the Telcordia (Belcore) SR-332 Method 1, Case 3,
ground fixed conditions, TCASE = +25°C, full load, natural air convection.
➄ The On/Off Control may be driven with open-collector logic or by applying appropriate
external voltages referenced to Common. The On/Off Control Input should use either an open
collector/open drain transistor or logic gate which does not exceed +VIN.
➅ Short circuit shutdown begins when the output voltage degrades approximately 2% from the
selected setting.
➆ Note that Maximum Power Derating curves indicate an average current at nominal input
voltage. At higher temperatures and/or lower airflow, the DC/DC converter will tolerate shorter
full current outputs if the total RMS current over time does not exceed the Derating curve.
➇ The user must install an external fuse in series with the input to protect against reverse polarity.
See Input Fusing.
2 4 - 6 0 W , S I N G L E O U T P U T D C / D C C O N V E R T E R S