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-
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
10μF
C3
10μF
2μF
ADJ
–V
IN
V
IN
LT137A
137A TA02
High Stability Regulator
7V
LM329B
R3
1.5k
1%
ADJ
–V
IN
V
IN
LT137A V
OUT
*R2 =
–V
OUT
R2*
+
R1
1k
1%
1μF
SOLID
TANTALUM
|
V
OUT
|
9.08 • 10
–3
137A TA03
– 908Ω
Dual Tracking Supply ±1.25V to ±20V
+V
IN
V
IN
LT317A V
OUT
ADJ
R1**
100Ω
1%
+V
OUT
+
2.2μF*
+
R2
C1
1μF
SOLID
TANTALUM
–V
OUT1
D1
1N4002
+
+
10μF
R2
5k
1%
R4
5k
1%
R3
5k
+
1N4002
R1
120Ω
+
R5**
100Ω
1%
2.2μF*
D2
1N4002
REG #1 V
OUT
ADJ
–V
IN
V
IN
LT337A V
OUT
–V
OUT
+
2μF
ADJ
V
IN
LT137A
137A TA02
+
1N4002
1μF
SOLID
TANTALUM
137A TA04
*SOLID TANTALUM
**R1 OR R5 MAY BE TRIMMED SLIGHTLY TO IMPROVE TRACKING
REG #2 V
OUT
–V
OUT2
Current Regulator
+
+
ADJ
(–)
–V
OUT3
137A TA05
+
2μF
ADJ
V
IN
LT137A
137A TA02
1μF
SOLID
TANTALUM
V
IN
C1
1μF
SOLID TANTALUM
(+)
R
S
I
I = 65μA +
1.25V
R
S
LT337A V
OUT
REG #N V
OUT
(0.8Ω < R
S
< 250Ω)
137afb
9
LINER [ LINEAR TECHNOLOGY ]
