TDK iQA Series manual Dual independent Trim

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 (-).

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

Rdown1 Rdown2

RTN

Circuit to decrease output voltage

Vin	(+)
On/	Off
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.

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:

Rdown = 301 − 4.01 ⋅(%Vo) ⋅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(+)	Rup1
	Rup2

Trim2

Trim1

RTN

Circuit to increase output voltage

©2002-2005 TDK Innoveta Inc.	℡ (877) 498-0099	16/19
iQAFullDatasheet080505 2.doc 8/3/2006