April 05 REVISION 02

SHEET 7 OF 16

Technical Reference Note

Ultra Low Profile

AVC 20W Series

11. Output Voltage adjustment

l When Adjust-pin (12pin) is left open, DC-DC converter applies nominal output voltage.

l Resistors connected between Adjust-pin(12pin) to Vout-pin (9~11pin) will decrease the output voltage

between 90% ~ 100% of the nominal output voltage.(Vout-Down control)

l Resistors connected between Adjust-pin(12pin) to GND-pin (5~8pin) will increase the output voltage

between 100% ~ 110% of the nominal output voltage.(Vout-Up control)

l The following equations give the required external-resistor value to adjust the output voltage to Voadj.

When you change the output voltage, it is necessary to evaluate the characteristics of DC-DC converter

at your board conditions.

l When Vout-Up is used, the input voltage must higher than the output voltage the following rate:

l

AVC (Vin=3.3V)

Vin > Vout+0.5V

AVC (Vin=5V)

Vin > Vout+1.0V

Trim down the output voltage,

Trim up the output voltage,

<Internal parameter of DC-DC converter>

Nominal Output

Voltage

[V]

1.0

1.2

1.5

1.8

2.0

2.5

3.3

Rx

[K

Ω]

4.7

3.6

4.7

4.7

5.6

6.8

8.2

Ry

[K

Ω]

29.73

14.64

16.16

8.40

7.00

6.80

4.60

Rz

[K

Ω]

1.0

1.0

2.2

5.6

10.0

15.0

18.0

Vs

[V]

0.864

0.963

1.162

1.154

1.111

1.250

1.186

Rz

-

Vs)

-

Ry(Voadj

-

Vs

*

Rx

Vs)

-

Ry(Voadj

*

Rx

R1

=

Open

R2

=

Rz

-

Vs

*

Rx

-

Vs)

-

Ry(Voadj

Vs

*

Ry

*

Rx

R2

=

Open

R1

=

9,10,11

12

R1

R2

Ry

Rx

Rz

GND

Vout

Adjust

Load

DC /DC

Vs