Datasheet

UWE-100-120W Series
Wide Input, Isolated Eighth-Brick DC-DC Converters
MDC_UWE-100-120W.C02 Page 32 of 34
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Remote Sense Note
The Sense and VOUT lines are internally connected through low value resis-
tors. Nevertheless, if the sense function is not used for remote regulation the
user should connect the +Sense to +V
OUT and –Sense to –VOUT at the DC-DC
converter pins.
UWE series converters have a sense feature to provide point of use regula-
tion, 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 regulate 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.
UWE series converters will compensate for drops between the output volt-
age at the DC-DC and the sense voltage at the DC-DC provided that:
[V
OUT(+) –VOUT(–)] –[Sense(+) –Sense (–)]  5% VOUT
Output overvoltage protection is monitored at the output voltage pin, not
the Sense pin. Therefore, excessive voltage differences between V
OUT and
Sense in conjunction with trim adjustment of the output voltage can cause the
overvoltage protection circuitry to activate (see Performance Specifi cations
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
UWE’s specifi ed rating or cause output voltages to climb into the output over-
voltage region. Also, the use of Trim Up and Sense combined may not exceed
+10% of V
OUT. Therefore, the designer must ensure:
(V
OUT at pins) x (IOUT)  rated output power
Soldering Guidelines
Murata Power Solutions recommends the specifi cations below when installing these
converters. These specifi cations vary depending on the solder type. Exceeding these
specifi cations may cause damage to the product. Your production environment may dif-
fer; therefore please thoroughly review these guidelines with your process engineers.
Wave Solder Operations for through-hole mounted products (THMT)
For Sn/Ag/Cu based solders:
Maximum Preheat Temperature 115° C.
Maximum Pot Temperature 270° C.
Maximum Solder Dwell Time 7 seconds
For Sn/Pb based solders:
Maximum Preheat Temperature 105° C.
Maximum Pot Temperature 250° C.
Maximum Solder Dwell Time 6 seconds
LOAD
+VOUT
+VIN
Sense Current
Contact and PCB resistance
losses due to IR drops
Contact and PCB resistance
losses due to IR drops
Sense Return
–VIN
ON/OFF
CONTROL
TRIM
+SENSE
–VOUT
–SENSE
I
OUT Return
I
OUT
Figure 9. Remote Sense Circuit Confi guration