rev.

page

date

DESCRIPTION: dc-dc converter

4 of 5

11/2009

20050

phone

phone 503.612.2300 fax

www.v-infinity.com

fax 503.612.2383

PART NUMBER: PK25

APPLICATION NOTES

1. OUTPUT TRIMMING

The output voltages are preset to nominal values as indicated by the models table at the factory. If desired, the output voltage may

optionally be trimmed to a different value (+/- 10%) with external resistors and/or potentiometer as shown below.

To trim the output voltage with fixed resistors, the output voltage can be calculated as follows.

Trim-Up

Trim-Down

FIGURE 2: TRIM-UP VOLTAGE SETUP

FIGURE 3: TRIM-DOWN VOLTAGE SETUP

the unit and are defined in Table 1. For example to trim up

the unit and are defined in Table 1. For example to trim down

as follows:

as follows:

R load

10KW

Trimpot

+Vin

-Vin

-Vo

Trim

+Vo

FIGURE 1. TRIMMING WITH

EXTERNAL POTENTIOMETER

2.5

2.5

2.5

2.5

2.5

2.5

2.5

1.25

Vr (V)

2.43

2.43

2.43

2.49

2.49

2.43

2.43

2.49

R2 (K

Ω)

Model

*PK25-D5-S3.3

PK25-DXX-D15

PK25-DXX-D12

PK25-DXX-D5

PK25-DXX-S15

PK25-DXX-S12

PK25-DXX-S5

PK25-DXX-S3.3

0.787

26.7

21

7.5

12.7

9.31

2.43

4.12

R1 (K

Ω)

Table 1

R load

R trim-up

+Vin

-Vin

+Vo

Trim

-Vo

R load

R trim-down

+Vin

-Vin

+Vo

Trim

-Vo

=

=

47.94 KΩ

2.43 · (25.2 - 2.5) - 2.5 · 21

2.5 · 21 · 2.43

=

=

326.68 KΩ

2.5 - 2.1 (22.8 - 2.5) · 2.43

(22.8 - 2.5) · 21 · 2.43

=

=

For more information, please visit the product page.