Bel Fuse Inc.

206 Van Vorst Street, Jersey City, NJ 07302

• Tel 201-432-0463 • Fax 201-432-9542 • www.belfuse.com

NON-ISOLATED DC/DC CONVERTERS

3.3V Input

0.9V-2.5V/3A Output

Output Trim Equations

Equations for calculating the trim resistor (in kΩ) given the desired adjusted voltage (Vadj) and the nominal

output voltage of the converter (Vnom) are shown below. The Trim Down resistor should be connected between

the Trim pin and Vout. The Trim Up resistor should be connected between the Trim pin and Ground. Only one of

the resistors should be used for any given application.

B

V

V

A

R

adj

nom

trimdown

−

−

=

D

V

V

C

R

nom

adj

trimup

−

−

=

Vnom

A

B

C

D

Notes

0.9 – 2.5

N/A

N/A

3.712

1.54

Vo=0.9V when Rtrim is open

2.5

7.9117

16.14

3.712

11.5

Vo=2.505V when Rtrim is open

1.8

4.6538

20.84

3.712

16.2

Vo=1.803V when Rtrim is open

1.5

3.2633

16.14

3.712

11.5

Vo=1.503V when Rtrim is open

1.2

1.8699

11.45

3.712

6.81

Vo=1.203V when Rtrim is open

0.9

N/A

N/A

3.712

33.2

Vo=0.903V when Rtrim is open

Module

Vout

Trim

GND

Rtrimdown

Module

Vout

Trim

GND

Rtrimup