Frequency (Hz)

0

10

20

30

40

50

60

70

80

10

100

1k

10k

100k

1m

D001

CADJ = 10 µF

CADJ = 0 µF

O

V

R2

R1

1

1.25

-

æ

ö

=

-

ç

÷

-

è

ø

LM237, LM337

SLVS047L – NOVEMBER 1981 – REVISED JANUARY 2015

www.ti.com

Typical Application (continued)

9.2.2 Detailed Design Procedure

VO is determined by the values of R1 and R2. Choosing R1 = 120 Ω means that about 10.42 mA of current will

flow through R1. The ~10 mA of current satisfies the minimum operating current and renders IREF negligible.

Since the current is coming from ground, the same amount of current will flow through R2. Therefore, the size of

R2 will be the dominant factor in adjusting VO. The relationship between R1, R2, and VO is as follows:

where VO is the output in volts.

(1)

9.2.3 Application Curves

Figure 4. Ripple Rejection Over Frequency

10 Power Supply Recommendations

For best performance, the difference in voltage between the output and input must be between -2.5 V and -37 V.

A 1-µF solid tantalum capacitor is required on the input pin if the regulator is more than 10 cm from the power

supply filter capacitor. A 1-µF solid tantalum or 10-µF aluminum electrolytic capacitor is required on the output

pin for stability.

10

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