+

R2

R1

1

x

= V

V

ADJ

OUT

¸

¹

·

¨

©

§

¸

©

§

¨

¨

¹

·

LP38851

www.ti.com

SNVS492C – JUNE 2007 – REVISED APRIL 2013

SETTING THE OUTPUT VOLTAGE

(Refer to TYPICAL APPLICATION CIRCUIT)

The output voltage is set using the external resistive divider R1 and R2. The output voltage is given by the

formula:

(5)

The resistors used for R1 and R2 should be high quality, tight tolerance, and with matching temperature

It is recommended that the values selected for R1 and R2 are such that the parallel value is less than 10 k

Ω.

( (R1 x R2) / (R1 + R2) )

≤ 10 kΩ

(6)

Table 1 lists some suggested, best fit, standard ±1% resistor values for R1 and R2, and a standard ±10%

similar results.

Table 1.

R1

R2

0.8V

1.07 k

Ω

1.78 k

Ω

220 pF

676 kHz

0.9V

1.50 k

Ω

1.87 k

Ω

180 pF

589 kHz

1.00V

1.00 k

Ω

1.00 k

Ω

270 pF

589 kHz

1.1V

1.65 k

Ω

1.37 k

Ω

150 pF

643 kHz

1.2V

1.40 k

Ω

1.00 k

Ω

180 pF

631 kHz

1.3V

1.15 k

Ω

715

Ω

220 pF

629 kHz

1.4V

1.07 k

Ω

590

Ω

220 pF

676 kHz

1.5V

2.00 k

Ω

1.00 k

Ω

120pF

663 kHz

1.6V

1.65 k

Ω

750

Ω

150 pF

643 kHz

1.7V

2.55 k

Ω

1.07 k

Ω

100 pF

624 kHz

1.8V

2.94 k

Ω

1.13 k

Ω

82 pF

660 kHz

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