Datasheet

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 confi guration. 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-
tors 2 to “N” will be improved by V
OUT
/1.25V compared
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
V
IN
–V
IN
R2*
7V
LM329B
V
OUT
–V
OUT
137A TA03
R1
1k
1%
R3
1.5k
1%
+
1μF
SOLID
TANTALUM
*R2 = – 908Ω
| V
OUT
|
9.08 • 10
–3
LT337A
ADJ
V
IN
(–) V
OUT
(+)
137A TA05
R
S
I
+
C1
1μF
SOLID TANTALUM
I = 65μA +
(0.8Ω < R
S
< 250Ω)
1.25V
R
S
LT337A
ADJ
V
IN
–V
IN
R3
5k
*SOLID TANTALUM
**R1 OR R5 MAY BE TRIMMED SLIGHTLY TO IMPROVE TRACKING
D2
1N4002
V
OUT
–V
OUT
137A TA04
R4
5k
1%
R2
5k
1%
R5**
100Ω
1%
LT317A
ADJ
V
IN
+V
IN
V
OUT
+V
OUT
+
2.2μF*
+
10μF
+
10μF
R1**
100Ω
1%
D1
1N4002
+
2.2μF*
REG #1
ADJ
V
IN
–V
IN
R2
V
OUT
–V
OUT1
137A TA02
R1
120Ω
1N4002
C1
1μF
SOLID
TANTALUM
+
C3
10μF
+
2μF
REG #2
LT137A
LT137A
ADJ
V
IN
V
OUT
–V
OUT2
137A TA02
1N4002
1μF
SOLID
TANTALUM
+
2μF
+
REG #N
LT137A
ADJ
V
IN
V
OUT
–V
OUT3
137A TA02
1μF
SOLID
TANTALUM
+
2μF
+