UEI15_10 Datasheet, PDF (11/14 Pages) Murata Power Solutions Inc. – Isolated Wide Input Range 15-Watt DC/DC Converters

UEI15 Series
Isolated Wide Input Range 15-Watt DC/DC Converters
disabled when the On/Off is grounded or brought to within a low voltage (see
Specifications) with respect to –VIN.
Negative-polarity devices are on (enabled) when the On/Off is grounded or
brought to within a low voltage (see Specifications) with respect to –VIN. The
device is off (disabled) when the On/Off is left open or is pulled high to +15VDC
max. with respect to –VIN.
ON/OFF CONTROL
+ Vcc
CONTROL
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 finite time in milliseconds (see
Specifications) 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.
-INPUT
There are three CAUTIONs for the On/Off Control:
Figure 7 – Driving the On/Off Control Pin (suggested circuit)
CAUTION: To retain full output circuit isolation, control the On/Off from the in-
put side ONLY. If you must control it from circuits in the output, use some form
of optoisolation to the On/Off Control. This latter condition is unlikely because
the device controlling the On/Off would have to remain powered on and not be
powered from the converter.
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, a switch 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.
On/Off Enable Control Ground Bounce Protection
To improve reliability, if you use a small signal transistor or other external
circuit to select the Remote On/Off control, make sure to return the LO side
directly to the –Vin power input on the DC/DC converter. To avoid ground
bounce errors, do not connect the On/Off return to a distant ground plane or
current-carrying bus. If necessary, run a separate small return wire directly to
the –Vin terminal. There is very little current (typically 1-5 mA) on the On/Off
control however, large current changes on a return ground plane or ground bus
can accidentally trigger the converter on or off. If possible, mount the On/Off
transistor or other control circuit adjacent to the converter.
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. 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
On/Off
Control
Transistor
Preferred location
of On/Off control
adjacent to -Vin
terminal
DC/DC Converter
+ Vin
On/Off Enable
-Vin return
Do not connect
control transistor
through remote
power bus
Ground plane or power return bus
Install separate
return wire for
On/Off control
with remote
transistor
Figure 8 – On/Off Enable Control Ground Bounce Protection
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20 Apr 2010 MDC_UEI15W.B37 Page 11 of 14