Adjusting the Output Voltage of the PTH12040W Wide-Output Adjust Power Module

Rset + 10 kW

0.8 V

V

O *

0.8 V

* 1.696 kW

(1)

PTH12040W

12

15

9

1

3

5

10 13

16

11

14

+Sense

-Sense

-Sense

GND

GND

17

+Sense

GND

R

1%

0.05W

SET

V

O

V

O

C

330 F

O

m

C

330 F

O

m

V Adj

O

PTH12040W

0.8 V to 5.5 V. The adjustment method requires the addition of a single external resistor, RSET, that must be

resistor for a number of standard voltages, along with the actual output voltage that this resistance value

provides. Figure 8 shows the placement of the required resistor.

For other output voltages, the value of the required resistor can either be calculated, or simply selected from the

range of values given in Table 3. The following formula can be used to calculate the adjust resistor value.

Voltages

PTH12040W

5.0

0.210

5.002

3.3

1.50

3.303

2.5

3.01

2.50

2.0

4.99

1.997

1.8

6.34

1.796

1.5

9.76

1.498

1.2

18.2

1.202

1.0

38.3

1.0

0.8

Open

0.8

(1)

A 0.05-W rated resistor may be used. The tolerance should be 1%, and the temperature stability, 100 ppm/°C (or

better). Place the resistor as close to the regulator as possible. Connect the resistor directly between pin 17 and the

nearest GND pin (pin 16) using dedicated PCB traces.

(2)

affects the stability of the regulator.

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