UCE-3.3/30-D48P-C Murata Power Solutions Inc, UCE-3.3/30-D48P-C Datasheet - Page 9

• Manufacturer Part Number: UCE-3.3/30-D48P-C
• Description: DC/DC Converters & Regulators 48Vin 3.3Vout 30A 99W Pos polarity
• Manufacturer: Murata Power Solutions Inc

Specifications of UCE-3.3/30-D48P-C

• Output Power: 99 W
• Input Voltage Range: 36 V to 75 V
• Input Voltage (nominal): 48 V
• Number Of Outputs: 1
• Output Voltage (channel 1): 3.3 V
• Output Current (channel 1): 30 A
• Isolation Voltage: 2.25 KV
• Package / Case Size: 2.3 in x 0.9 in x 0.4 in
• Output Voltage: 3.3 V
• Product: Isolated
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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 shut-
down circuitry. If environmental conditions cause the temperature of the DC/
DC’s to rise above the Operating Temperature Range up to the shutdown tem-
perature, 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 adjacent to the
switching controller, approximately in the center of the unit. See the Perfor-
mance and Functional Specifi cations.
shut down suddenly without warning. Be sure to thoroughly test your applica-
tion to avoid unplanned thermal shutdown.
Temperature Derating Curves
The graphs in the next section 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.
CAUTION: If you operate too close to the thermal limits, the converter may
+OUTPUT
−OUTPUT
+SENSE
−SENSE
Figure 3. Measuring Output Ripple and Noise (PARD)
C1 = 0.1μF CERAMIC
C2 = 10μF TANTALUM
LOAD 2-3 INCHES (51-76mm) FROM MODULE
6
5
9
8
C1
COPPER STRIP
COPPER STRIP
C2
SCOPE
www.murata-ps.com
R
LOAD
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.
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.
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.
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.
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.
Note that the temperatures are of the ambient airfl ow, not the converter
Murata Power Solutions makes Characterization measurements in a closed
CAUTION: If you exceed these Derating guidelines, the converter may have
If the fault condition persists and the output voltage climbs to excessive
Current limiting inception is defi ned as the point at which full power falls
Isolated, High-Density, Eighth-Brick
Low Profi le DC/DC Converters
21 Feb 2011
email: [e-mail]
UCE Series
MDC_UCE.A30 Page 9 of 17