Datasheet
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ULS 60-Watt Series
Sixteenth-brick DOSA-Compatible,
Isolated DC/DC Converters
MDC_ULS Series.C02 Page 13 of 24
Performance Specification Notes
➀ All specifications are typical unless noted. Ambient temperature =
+25°Celsius, Vin is nominal, output current is maximum rated nominal.
External output capacitance is 1 µF multilayer ceramic paralleled with
10µF electrolytic. All caps are low ESR. These capacitors are necessary for
our test equipment and may not be needed in your application.
Testing must be kept short enough that the converter does not appreciably
heat up during testing. For extended testing, use plenty of airflow. See
Derating Curves for temperature performance. All models are stable and
regulate within spec without external cacacitance.
➁ Input Ripple Current is tested and specified over a 5-20 MHz bandwidth
and uses a special set of external filters only for the Ripple Current speci-
fications. Input filtering is Cin = 33 µF, Cbus = 220 µF, Lbus = 12µH. Use
capacitor rated voltages which are twice the maximum expected voltage.
Capacitors must accept high speed AC switching currents.
➂ Note that Maximum Current Derating Curves indicate an average current
at nominal input voltage. At higher temperatures and/or lower airflow, the
converter will tolerate brief full current outputs if the average 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.
➃ Mean Time Before Failure (MTBF) is calculated using the Telcordia
(Belcore) SR-332 Method 1, Case 3, Issue 1, ground fixed conditions. Oper-
ating temperature = +30°C, full output load, natural air convection.
➄ The output may be shorted to ground indefinitely with no damage. The
Output Short Circuit Current shown in the specifications is an average con-
sisting of very short bursts of full rated current to test whether the output
circuit can be repowered.
➅ The On/Off Control is normally driven from a switch or relay. An open
collector/open drain transistor may be used in saturation and cut-off
(pinch-off) modes. External logic may also be used if voltage levels are
fully compliant to the specifications.
➆ Regulation specifications describe the deviation as the input line voltage
or output load current is varied from a nominal midpoint value to either
extreme (50% load).
➇ Do not exceed maximum power ratings, Sense limits or output overvoltage
when adjusting output trim values.
➈ At zero output current, Vout may contain components which slightly
exceed the ripple and noise specifications.
➉ Output overload protection is non-latching. When the output overload
is removed, the output will automatically recover.
All models are fully operational and meet published specifications,
including “cold start” at –40°C.
The converter will shut off if the input falls below the undervoltage thresh-
old. It will not restart until the input exceeds the Input Start Up Voltage.
Short circuit shutdown begins when the output voltage degrades approxi-
mately 2% from the selected setting.
Output noise may be further reduced by installing an external filter. See
the Application Notes. Use only as much output filtering as needed and no
more. Larger caps (especially low-ESR ceramic types) may slow transient
response or degrade dynamic performance. Thoroughly test your applica-
tion with all components installed.
To avoid damage or unplanned shutdown, do not sink appreciable reverse
output current.
If reverse polarity is accidentally applied to the input, always connect an
external fast blow input fuse in series with the +Vin input.
Although extremely unlikely, failure of the internal components of this
product may expose external application circuits to dangerous voltages,
currents, temperatures or power levels. Please thoroughly verify all appli-
cations before committing them to service. Be sure to include appropri-
ately rated FUSES (see specifications and Application Notes) to reduce the
risk of failure.
If Sense is not wired to an external load, connect sense pins to their
respective Vout pins. Do not leave sense unconnected.
All models use fixed switching frequencies.
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