Datasheet

www.murata-ps.com/support
ULT Series
Thirty-Second-Brick Isolated DC/DC Converters
with 2:1 Wide Input Range
MDC_ULT Series.F05 Page 10 of 26
Performance Specifi cation Notes
➀ All specifi cations are typical unless noted. Ambient temperature =
+25°Celsius, V
IN is nominal, output current is maximum rated nominal.
External output capacitance consists of 400µF capacitors across output
pins; one 33µF low ESR, and three 1µF external input capacitors. All caps
are low ESR.
Testing must be kept short enough that the converter does not appreciably
heat up during testing. For extended testing, use plenty of airfl ow. See
derating curves for temperature performance. All models are stable and
regulate within spec without external cacacitance.
➁ Input Ripple Current is tested and specifi ed over a 5-20 MHz bandwidth
and uses a special set of external fi lters only for the Ripple Current speci-
fi cations. Input fi ltering is C
IN = 33 µF, CBUS = 220 µF, LBUS = 12µH. 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 airfl ow, 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 (Bel-
core) SR-332 Method 1, Case 3, Issue 1, ground fi xed conditions. Operat-
ing temperature = +25°C, full output load, natural air convection.
➄ The output may be shorted to ground indefi nitely with no damage. The
Output Short Circuit Current shown in the specifi cations 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 pin allows the converter to be turned on or off by an external
device such as a switch, a transistor, a logic gate, or an optical isolator.
If the “logic pin” is left fl oating the measured voltage will be outside the
limit's in the data sheet. Those numbers defi ne the levels needed for the
“control function” to take place and do not represent the voltage that may
be present on the logic pin.
➆ Regulation specifi cations 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 Output overload protection is non-latching. When the output overload
is removed, the output will automatically recover.
➉ All models are fully operational and meet published specifi cations,
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.
Output noise may be further reduced by installing an external fi lter. See
the Application Notes. Use only as much output fi ltering 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.
If reverse polarity is accidentally applied to the input, always connect an
external fast blow input fuse in series with the +V
IN 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 ap-
plications before committing them to service. Be sure to include appropri-
ately rated FUSES (see specifi cations and Application Notes) to reduce the
risk of failure.
Special care should be exercised so that Input Voltage Transient does not
exceed specifi ed Max 100V/100ms. At normal input a large transient spike
can be generated as a result of distribution inductance and high inrush
current charging input cap on converter. This can be eliminated with 33µF
electrolytic capacitor mounted close to Converter input. The series resis-
tance (500mΩ < ESR < 700mΩ) is essential in this solution.
11
12
13
14
15