NEGATIVE ADJUSTABLE

VOLTAGE REGULATOR

Semelab Limited

Semelab Limited

Semelab Limited

Semelab Limited

Coventry Road, Lutterworth, Leicestershire, LE17 4JB

Telephone +44 (0) 1455 556565

Fax +44 (0) 1455 552612

Document Number 8380

Issue 1

Page 6 of 7

APPLICATIONS INFORMATION

High Stability Regulator

The output stability, load regulation, 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 has 20PPM/°C maximum drift and about 10

times lower noise than the regulator.

Multiple Tracking Regulators

In the application shown below, regulator #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 -2V. Load regulation of regulators #2

to “N” will be improved by VOUT / 1.25V compared to a

standard, so regulator #1 should be the one which has

the lowest load current.

Dual Tracking Supply

Current Regulator

* Solid Tantalum

** R1 & R5 maybe trimmed slightly to improve tracking

R3

1.5k

1%

ADJ

IP137

R1

1k

1%

1µF

SOLID

TANTALUM

7V

R2

*

(

)

V

OUT

– 908 Ω

R2 =

*

C3

10µF

R2

ADJ

IP137

V

IN

V

OUT

1N4002

R1

120 Ω

ADJ

IP137

V

IN

V

OUT

1N4002

2µF

C1

1µF

SOLID

TANTALUM

REG #1

2µF

REG #2

1µF

SOLID

TANTALUM

OUT2

–V

ADJ

IP137

V

IN

V

OUT

1N4002

2µF

REG #N

OUT N

–V

1µF

SOLID

TANTALUM

ADJ

IP137

V

IN

V

OUT

D2

1N4002

–V

OUT

IN

–V

R5**

100 Ω

1%

R3

5k

10µF

V

IN

V

OUT

ADJ

IP137

R1**

100 Ω

1%

10µF

2.2

µF

2.2

µF

D1

1N4002

IN

+V

+V

OUT

R2

5k

1%

R4

5k

1%

*

*

ADJ

V

IN

V

OUT

(–)

I

(+)

C1

1µF

SOLID

TANATALUM

IP137

0.8 Ω ≤

≤ 250Ω

R

S

I = 65µA +

1.25 V

R

S

IP137

IP137

IP137

IP137

IP137

IP137

IP137