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APPLICATION INFORMATION

ADJUSTING THE OUTPUT VOLTAGE

V

I

C

330 F

(Optional)

O

m

C

560 F

(Required)

I

m

GND

V

O

V Sense

O

R

SET

1%

0.1W

PTH12010x

1

10

4

5

6

2

3

9

7

GND

8

NOTES

PTH12010W, PTH12010L

SLTS205G – JUNE 2003 – REVISED FEBRUARY 2007

The VO Adjust control (pin 4) sets the output voltage of the PTH12010 product. The adjustment range is from 1.2

V to 5.5 V for the W-suffix modules, and 0.8 V to 1.8 V for L-suffix modules. The adjustment method requires the

addition of a single external resistor, RSET, that must be connected directly between the VO Adjust and GND

pins.Table 1 gives the standard value of the external resistor for a number of standard voltages, along with the

actual output voltage that this resistance value provides. For other output voltages, the value of the required

resistor can either be calculated using Equation 1, or simply selected from the range of values given in Table 3.

Figure 11 shows the placement of the required resistor.

Table 1. Standard Values of RSET for Standard Output Voltages

PTH12010W

PTH12010L

VO (Required)

RSET

VO (Actual)

RSET

VO(Actual)

5 V

280

Ω

5.009 V

N/A

N/A

3.3 V

2.0 k

Ω

3.294 V

N/A

N/A

2.5 V

4.32 k

Ω

2.503 V

N/A

N/A

2 V

8.06 k

Ω

2.010 V

N/A

N/A

1.8 V

11.5 k

Ω

1.081 V

130

Ω

1.800 V

1.5 V

24.3 k

Ω

1.506 V

3.57 k

Ω

1.499 V

1.2 V

Open

1.200 V

12.1 k

Ω

1.201 V

1.1 V

N/A

N/A

18.7 k

Ω

1.101 V

1.0 V

N/A

N/A

32.4 k

Ω

0.999 V

0.9 V

N/A

N/A

71.5 k

Ω

0.901 V

0.8 V

N/A

N/A

Open

0.800 V

Figure 11. Vo Adjust Resistor Placement

1. A 0.05 W rated resistor may be used. The tolerance should be 1%, with temperature stability of 100

ppm/

°C (or better). Place the resistor as close to the regulator as possible. Connect the resistor directly

between pins 4 and 7 using dedicated PCB traces.

2. Never connect capacitors from VO Adjust to either GND or VO. Any capacitance added to the VO Adjust

pin affects the stability of the regulator.

8

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