9

137afb

LT137A/LM137

LT337A/LM337

TYPICAL APPLICATIONS

A high stability regulator is illustrated in the application

circuit shown to the right. The output stability, load regula-

tion, line regulation, thermal regulation, temperature drift,

long term drift, and noise can be improved by a factor of

6.6 over the standard regulator configuration. This assumes

a zener whose drift and noise is considerably better than

the regulator itself. The LM329B has 20ppm/°C maximum

drift and about 10 times lower noise than the regulator.

In the application shown below, regulators #2 to “N” will

track regulator #1 to within ±24mV initially, and to ±60mV

over all load, line, and temperature conditions. If any

regulator output is shorted to ground, all other outputs will

drop to approximately ≈ –2V. Load regulation of regula-

to a standard regulator, so regulator #1 should be the one

which has the lowest load current.

Multiple Tracking Regulators

High Stability Regulator

Dual Tracking Supply ±1.25V to ±20V

Current Regulator

LT137A

ADJ

R2*

7V

LM329B

137A TA03

R1

1k

1%

R3

1.5k

1%

+

1μF

SOLID

TANTALUM

*R2 =

– 908Ω

LT337A

ADJ

(–)

(+)

137A TA05

I

+

C1

1μF

SOLID TANTALUM

I = 65μA +

1.25V

LT337A

ADJ

R3

5k

*SOLID TANTALUM

**R1 OR R5 MAY BE TRIMMED SLIGHTLY TO IMPROVE TRACKING

D2

1N4002

137A TA04

R4

5k

1%

R2

5k

1%

R5**

100Ω

1%

LT317A

ADJ

+

2.2μF*

+

10μF

+

10μF

R1**

100Ω

1%

D1

1N4002

+

2.2μF*

REG #1

ADJ

R2

137A TA02

R1

120Ω

1N4002

C1

1μF

SOLID

TANTALUM

+

C3

10μF

+

2μF

REG #2

LT137A

LT137A

ADJ

137A TA02

1N4002

1μF

SOLID

TANTALUM

+

2μF

+

REG #N

LT137A

ADJ

137A TA02

1μF

SOLID

TANTALUM

+

2μF

+