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date 03/28/2016

│ page 13 of 14

CUI Inc

│ SERIES: PRD15 │ DESCRIPTION: DC-DC CONVERTER

Output Voltage Trimming

Theoutputvoltagecanbeadjustedbyusingthetrimpinandtheuseofeitheranexternaltrimpotoftheuseofasingle

fixedresistor(SeeFigures3~5below).Trimmingresistorsshouldhavealowtemperaturecoefficient(±100ppm/°Cor

less) and be mounted close to the converter. Forinputvoltage<20Vdc,PRD15-Q48-S5canonlybetrimmeddown. If

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

LOAD

75-22

TURNS

+VOUT

TRIM

−VOUT

−VIN

ON/OFF

CONTROL

+VIN

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 3 Trim Adjustments Using

A Trimpot

Figure 5 Trim Adjustments To Increase

Output Voltage Using A Fixed Resistor

- B

- B

A

Figure 6. Driving The On/Off Control Pin

(Suggested Circuit)

Note: R

R

V

V

ON/OFF CONTROL

CONTROL

+ Vcc

-VIN

Vout

A

B

C

3.3

12775

2050

5110

5

12775

2050

5110

12

25000

5110

10000

15

25000

5110

10000

Remote On/Off Control

TheDC-DCconvertercanbeorderedwitheitherpositiveornegativelogic.Seepage2forenable/disabledetailsforboth

positive and negative logic options. Dynamic control of the On/Off function should be able to sink appropriate signal

currentwhenbroughtlowandwithstandappropriatevoltagewhenbroughthigh.Beawarethatthereisafinitetimein

millisecondsbetweenthethetimeofOn/Offcontrolactivationandstable,regulatedoutput.Thistimewillvaryslightly

with output load type and current and input conditions.

Cautions when using the On/Off control:

1. Toretainfulloutputcircuitisolation,controltheOn/Offfromtheinputsideonly.

2. 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.

3. Do not apply voltages to the On/Off pin when there is no input power voltage, otherwise the converter may be

permanently damaged.

For more information, please visit the product page.