UHE Datasheet, PDF (15/16 Pages) Murata Manufacturing Co., Ltd. – Isolated, High Effi ciency, 1.6" × 2" 2-10 Amp, 12-30 Watt DC/DC Converters

Trim Equations
Trim Up
Trim Down
UHE-1.2/10000-D12, -D24, -D48
0.4432(VO – 0.397)
R1 (k7) =
– 1.413
VO – 1.2
0.397
R2 (k7) =
– 1.413
1.2 – VO
Trim Down
Trim Up
UHE-1.5/10000-D12, -D24, -D48
0.459(VO – 0.7096)
R1 (k7) =
– 3.169
1.5 – VO
0.3232
R2 (k7) =
– 3.169
VO – 1.5
UHE-1.8/10000-D12, -D24, -D48
R1 (k7) = ^{1.027(VO – 0.9352)} – 7.596
1.8 – VO
0.9647
R2 (k7) =
– 7.596
VO – 1.8
UHE-2.5/10000-D12, -D24, -D48
2.226(VO – 0.9625)
R1 (k7) =
– 7.503
2.5 – VO
2.142
R2 (k7) =
– 7.503
VO – 2.5
UHE-3.3/7500-Q12, -Q24, -D48
R1 (k7) = ^{3.21(VO – 1.759)} – 22.42
3.3 – VO
5.65
R2 (k7) =
– 22.42
VO – 3.3
UHE-5/5000-Q12, -Q48, UHE-5/6000-D48, -Q48
2.15(VO – 2.592)
R1 (k7) =
– 15.52
5 – VO
5.58
R2 (k7) =
– 15.52
VO – 5
UHE-12/2500-D12, -D24, -D48, -Q12, -Q48
10(VO – 2.5)
R1 (k7) =
– 34.8
12 – VO
29.5
R2 (k7) =
– 34.8
VO – 12
UHE-15/2000-D12, -D24, -D48
13.3(VO – 2.5)
R1 (k7) =
– 38.3
15 – VO
37.875
R2 (k7) =
– 38.3
VO – 15
UHE-15/2000-Q12, -Q48
13.3(VO – 2.5)
R1 (k7) =
– 34.8
15 – VO
37.875
R2 (k7) =
– 34.8
VO – 15
UHE-3.3/7500-D48T (Quantity order only)
R1 (kȍ) = (2.54/y – 4.08)/2
where y = (3.3 – VO)/3.3
R2 (kȍ) = 1.55/2y
where y = (VO – 3.3)/3.3
UHE-5/6000-Q48T, -D48T (Quantity order only)
R1 (kȍ) = 1.25/y – 2.69
where y = (5 – VO)/5
R2 (kȍ) = 1.25/y
where y = (VO – 5)/5
www.murata-ps.com/support
UHE Series
Isolated, High Efficiency, 1.6" × 2"
2-10 Amp, 12-30 Watt DC/DC Converters
Trim adjustments greater than the specified ±5% 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 adjustment of the
output voltage, can cause the overvoltage protection circuitry to activate (see
Performance Specifications 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 specified rating or cause output voltages
to climb into the output overvoltage region. Therefore:
(VOUT at pins) x (IOUT) < = rated output power
Note: Resistor values are in kΩ. Adjustment accuracy is subject to resistor
tolerances and factory-adjusted output accuracy. VO = desired output voltage.
Remote Sense (Optional on 1.2-5VOUT models)
Note: The Sense and VOUT lines are internally connected through 10: resis-
tors. 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.
UHE series converters have a sense feature to provide point of use regulation,
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 regu-
late 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.
UHE 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 (–)] d 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 Specifications
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 UHE’s specified rating or cause output voltages to climb into the output
overvoltage region. Therefore, the designer must ensure:
(VOUT at pins) × (IOUT) d rated output power
2 _–INPUT
4 _ON/OFF
CONTROL
1
+INPUT
+OUTPUT
Contact and PCB resistance
losses due to IR drops
6
5
+SENSE
TRIM 9
8
–SENSE
7
–OUTPUT
IOUT
Sense Current
Sense Return
LOAD
IOUT Return
Contact and PCB resistance
losses due to IR drops
Figure 9. Remote Sense Circuit Configuration
MDC_UHE_12-30W Series.C01 Page 15 of 16