cui.com

date 05/20/2016

│ page 12 of 13

CUI Inc

│ SERIES: PRD25 │ DESCRIPTION: DC-DC CONVERTER

Output Voltage Trimming

Theoutputvoltagecanbeadjustedbyusingthetrimpinandasinglefixedresistor(seeFigures4&5).Trimming

resistorsshouldhavealowtemperaturecoefficient(±100ppm/°Corless)andbemountedclosetotheconverter.Ifthe

trim function is not needed, leave the trim pin open.

APPLICATION NOTES

+VOUT

TRIM

ON/OFF

CONTROL

−VIN

LOAD

−VOUT

+VIN

Figure 4 Trim Adjustments To Decrease

Output Voltage Using A Fixed Resistor

LOAD

+VOUT

TRIM

ON/OFF

CONTROL

−VIN

−VOUT

+VIN

Figure 5 Trim Adjustments To Increase

Output Voltage Using A Fixed Resistor

Figure 6. Driving The On/Off Control Pin

(Suggested Circuit)

Note: R

R

V

V

ON/OFF

CONTROL

-VIN

+VCC

Vout

A

B

C

3.3

12775

2050

5110

5

12775

2050

5110

12

25000

5110

10000

Remote On/Off Control

TheDC-DCconvertercanbeorderedwitheitherpositiveornegativelogic.Seepage2forenable/disabledetailsforboth

positiveandnegativelogicoptions.DynamiccontroloftheOn/Offfunctionshouldbeabletosinkappropriatesignal

currentwhenbroughtlowandwithstandappropriatevoltagewhenbroughthigh.Beawarethatthereisafinitetimein

millisecondsbetweenthethetimeofOn/Offcontrolactivationandstable,regulatedoutput.Thistimewillvaryslightly

with output load type and current and input conditions.

CautionswhenusingtheOn/Offcontrol:

1. Toretainfulloutputcircuitisolation,controltheOn/Offfromtheinputsideonly.

2.WhileitispossibletocontroltheOn/Offwithexternallogicifyoucarefullyobservethevoltagelevels,the

preferred circuit is either an open drain/open collector transistor, a switch, or a relay.

3.DonotapplyvoltagestotheOn/Offpinwhenthereisnoinputpowervoltage,otherwisetheconvertermaybe

permanently damaged.

For more information, please visit the product page.