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Adjusting the Output Voltage

R

= 10 k

x

SET

W

0.8 V

V

- 0.8 V

O

= 2.49 kW

(1)

PTV05010W

SLTS242 – FEBRUARY 2005

APPLICATION INFORMATION (continued)

Table 1. Input/Output Capacitors (continued)

Capacitor Characteristics

Quantity

Max ESR

Max Ripple

Capacitor Vendor,

Vendor

Working

Optional

Value

at 100

Current at

Physical Size

Input

Type/Series (Style)

Part Number

Voltage

Output

(µF)

kHz

85

°C (Irms)

(mm)

Bus

(V)

Bus

(

Ω)

(mA)

Murata, Ceramic X5R

6.3

100

0.002

—

3225

≤ 3

GRM32ER60J107M

(SMD)

6.3

47

≤ 5

GRM32ER60J476M

16

22

≤ 5

GRM32ER61C226K

16

10

≤ 5

GRM32DR61C106K

TDK, Ceramic X5R

6.3

100

0.002

—

3225

≤ 3

C3225X5R0J107MT

(SMD)

6.3

47

≤ 5

C3225X5R0J476MT

16

22

≤ 5

C3225X5R1C226MT

16

10

≤ 5

C3225X5R1C106MT

resistor, the output voltage is set to its lowest value. Table 2 gives the preferred value of the external resistor for

a number of standard voltages, along with the actual output voltage that this resistance value provides. Figure 6

shows the placement of the required resistor.

(Required)

(Standard Value)

(Actual)

3.3 V

698

Ω

3.309 V

2.5 V

2.21 k

Ω

2.502 V

2 V

4.12 k

Ω

2.010 V

1.8 V

5.49 k

Ω

1.803 V

1.5 V

8.87 k

Ω

1.504 V

1.2 V

17.4 k

Ω

1.202 V

1 V

36.5 k

Ω

1.005 V

0.8 V

Open

0.800 V

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. Equation 1 may be used for calculating the adjust resistor value.

8