www.murata-ps.com

Note: Resistor values are in k

Ω. Adjustment accuracy is subject to resistor

through low value resistors. Nevertheless, if the sense function is not used for

ULE 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.

ULE series converters will compensate for drops between the output voltage

at the DC/DC and the sense voltage at the DC/DC provided that:

Output overvoltage protection is monitored at the output voltage pin, not

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

ULE’s specified 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

≤ rated output power

UP

–

10.2

(kΩ) =

–

10.2

16.31

DOWN

3.3 Volt Output

UP

–

10.2

(kΩ) =

–

10.2

25.01

DOWN

5 Volt Output

UP

–

10.2

UP

–

10.2

(kΩ) =

–

10.2

60.45

DOWN

(kΩ) =

–

10.2

124.2

DOWN

12 Volt Output

24 Volt Output

Trim Equations

Trim Up

Trim Down

Figure 9. Remote Sense Circuit Configuration

LOAD

+OUTPUT

–INPUT

Sense Current

Contact and PCB resistance

losses due to IR drops

Contact and PCB resistance

losses due to IR drops

Sense Return

+INPUT

ON/OFF

CONTROL

TRIM

+SENSE

–OUTPUT

–SENSE

ULE Series

Isolated, High Density

, Eighth-Brick

1.25–30 Amp, DC/DC Converters

MDC_ULE Series.C11 Page 11 of 23

Soldering Guidelines

Murata Power Solutions recommends the specifications below when installing these

converters. These specifications vary depending on the solder type. Exceeding these

specifications may cause damage to the product. Be cautious when there is high

atmospheric humidity. We strongly recommend a mild pre-bake (100 ºC. for 30

minutes). Your production environment may differ therefore please thoroughly review

these guidelines with your process engineers.

Reflow Solder Operations for surface-mount products (SMT)

For Sn/Ag/Cu based solders:

Preheat Temperature

Less than 1 ºC. per second

Time over Liquidus

45 to 75 seconds

Maximum Peak Temperature

260 ºC.

Cooling Rate

Less than 3 ºC. per second

For Sn/Pb based solders:

Preheat Temperature

Less than 1 ºC. per second

Time over Liquidus

60 to 75 seconds

Maximum Peak Temperature

235 ºC.

Cooling Rate

Less than 3 ºC. per second

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