Datasheet

PAH-28 Vout, 350-Watt Series
Isolated, 350-Watt, Half-Brick DC-DC Converters
MDC_PAH-28Vout-350W.B05 Page 19 of 21
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Trim Equations
Where Vref = +1.225 Volts and ∆ is the desired output voltage change. Note
that "∆" is given as a small fraction, not a percentage.
A single resistor connected between Trim and +Sense will increase the output
voltage. A resistor connected between Trim and –Sense will decrease the output.
Remote On/Off Control
On the input side, a remote On/Off Control can be ordered with either logic type.
Positive models are enabled when the On/Off pin is left open or is pulled
high to +15V with respect to –Vin. Some models will also turn on at lower
intermediate voltages (see Specifi cations). Positive-logic devices are disabled
when the On/Off is grounded or brought to within a low voltage (see Specifi ca-
tions) with respect to –Vin.
Negative-logic devices are on (enabled) when the On/Off is grounded or
brought to within a low voltage (see Specifi cations) with respect to –Vin. The
device is off (disabled) when the On/Off is pulled high to +15V with respect
to –Vin.
Figure 7. Trim adjustments to Decrease Output Voltage using a Fixed Resistor
Figure 8. Driving the Positive Logic On/Off Control Pin
Figure 9. Driving the Negative Logic On/Off Control Pin
Dynamic control of the On/Off function should be able to sink appropriate
signal current when brought low and withstand appropriate voltage when
brought high. Be aware too that there is a fi nite time in milliseconds (see
Specifi cations) between the time of On/Off Control activation and stable,
regulated output. This time will vary slightly with output load type and current
and input conditions.
There are two CAUTIONs for the On/Off Control:
CAUTION: While it is possible to control the On/Off with external logic if you
carefully observe the voltage levels, the preferred circuit is either an open
drain/open collector transistor or a relay (which can thereupon be controlled by
logic).
CAUTION: Do not apply voltages to the On/Off pin when there is no input
power voltage. Otherwise the converter may be permanently damaged.
+VOUT
+SENSE
TRIM
–SENSE
–VOUT
+VIN
ON/OFF
CONTROL
–VIN
LOAD
R TRIM DOWN
ON/OFF
CONTROL
–VIN
+VIN +VCC
V
nominal
R
adj_up
(
in kΩ
)
= - - 2
V
nominal
x (1+∆) 1
∆
1.225 x ∆
where ∆ =
V
nominal
-V
out
R
adj_down
(
in kΩ
)
= - 2
1
∆
where ∆ =
V
out
-V
nominal
V
nominal
ON/OFF CONTROL
CONTROL
+ Vcc
– VIN
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
differ; 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: For Sn/Pb based solders:
Maximum Preheat Temperature 115° C. Maximum Preheat Temperature 105° C.
Maximum Pot Temperature 270° C. Maximum Pot Temperature 250° C.
Maximum Solder Dwell Time 7 seconds Maximum Solder Dwell Time 6 seconds