TDK Dualeta iQA Series Datasheet page 16

Advance Data Sheet: Dualeta™ iQA Series – Dual Quarter Brick
Remote On/Off
The power modules have an internal remote
On/Off circuit. The user must supply an
open-collector or compatible switch between
the Vin (-) pin and the On/Off pin. The
maximum voltage generated by the power
module at the on/off terminal is 15V. The
maximum allowable leakage current of the
switch is 50uA. The switch must be
capable of maintaining a low signal Von/off
< 1.2V while sinking 1mA.
The standard on/off logic is positive logic.
The power module will turn on if the On/Off
is left open and will be off if the On/Off is
connected to Vin (-). If the positive logic
circuit is not being used, the On/Off should
be left open.
An optional negative logic is available. The
power module will turn on if the On/Off
terminal is connected to Vin (-), and it will be
off if the On/Off is left open. If the negative
logic feature is not being used, On/Off
should be shorted to Vin (-).
On/Off Circuit for positive or negative
logic
Output Voltage Adjustment
The output voltages of the power module
may be adjusted by using an external
resistor connected between the Trim
terminal and either the Vo (+) or RTN
terminal. If the output voltage adjustment
feature is not used, the Trim pin(s) should
be left open. Care should be taken to avoid
injecting noise into the power module's trim
pin. A small 0.01uF capacitor between the
power module's trim pin and RTN pin may
help avoid this.
©2002-2005 TDK Innoveta Inc.
iQAFullDatasheet080505 2.doc 8/3/2006
Vin (+)
On/ Off
Vin(-)
℡
(877) 498-0099
Two trim configurations are offered on the
iQA-series. The standard Dual Independent
Trim offers wide range independent
adjustment of either output, using two trim
pins. The optional Single Tracking Trim
adjusts both outputs together by 10%
according to industry standard resistor
tables. Only a single trim pin is provided.
Dual independent Trim
Vo1(+)
Vo2(+)
Trim2
Trim1
RTN
Circuit to decrease output voltage
With a resistor between the trim and RTN
terminals, the output voltage is adjusted
down. To adjust the output voltage down a
percentage of Vout (%Vo) from Vo,nom, the
trim resistor should be chosen according to
the following equation:
− ⋅
301 4.01 %Vo ( )
Rdown = ⋅ 1000
%Vo
The current limit set point does not increase
as the module is trimmed down, so the
available output power is reduced.
Vo1(+)
Vo2(+)
Trim2
Trim1
RTN
Circuit to increase output voltage
Rdown1 Rdown2
Rup1
Rup2
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