UEI15_11 Datasheet, PDF (15/16 Pages) Murata Manufacturing Co., Ltd. – 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.
Through-hole Soldering Guidelines
Murata Power Solutions recommends the TH soldering specifications below when install-
ing these converters. These specifications vary depending on the solder type. Exceeding
these specifications 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:
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
SMT Reflow Soldering Guidelines
The surface-mount reflow solder profile shown below is suitable for SAC305 type lead-
free solders. This graph should be used only as a guideline. Many other factors influence
the success of SMT reflow soldering. Since your production environment may differ,
please thoroughly review these guidelines with your process engineers.
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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14 Mar 2011 MDC_UEI15W.B42 Page 15 of 16