SG137T Microsemi Analog Mixed Signal Group, SG137T Datasheet - Page 5

• Manufacturer Part Number: SG137T
• Description: IC VOLTAGE REG NEG ADJ TO-39
• Manufacturer: Microsemi Analog Mixed Signal Group

Specifications of SG137T

• Regulator Topology: Negative Adjustable
• Voltage - Output: -1.2 ~ -37 V
• Voltage - Input: Down to -36V
• Number Of Regulators: 1
• Current - Output: 100mA
• Current - Limit (min): 500mA
• Operating Temperature: -55°C ~ 150°C
• Mounting Type: Through Hole
• Package / Case: TO-39
• Lead Free Status / RoHS Status: Lead free by exemption / RoHS compliant by exemption
• Voltage - Dropout (typical): -

2/92 Rev 1.1 2/94
Copyright
APPLICATION INFORMATION
the SG137A flows from input to output. If this current is not
absorbed by the load, the output of the regulator will rise above
the regulated value. The current drawn by R
high enough to absorb the current, but care must be taken in no–
load situations where R
value for the operating current, which must be absorbed, is 5mA
for the SG137A, If input-output voltage differential is less than
10V, the operating current that must be absorbed drops to 3mA.
The output stability, load regulation, line regulation, thermal
TYPICAL APPLICATIONS
regulation, temperature drift, long term drift, and noise, can be
improved by a factor of 6.6 over the standard regulator configu-
ration. This assumes a zener whose drift and noise is considera-
bly 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 Figure 8, regulators #2 to #N will track
regulator #1 to within ±24mV initially, and to ±60mV over all load,
line, and temperature conditions.
shorted to ground, all other outputs will drop to -2V. Load
regulation of regulators #2 to #N will be improved by V
compared to a standard regulator, so regulator #1 should be the
one which has the lowest load current.
1994
FIGURE 9 - HIGH STABILITY REGULATOR
FIGURE 10 - CURRENT REGULATOR
1
and R
2
have high values. The maximum
(continued)
If any regulator output is
1
and R
2
is normally
OUT
/1.25V
5
EXAMPLES:
1. A precision 10V regulator to supply up to 1Amp load current.
2. A 15V regulator to run off batteries and supply 50mA.
a. Select R
b. Calculate R
V
a. To minimize battery drain, select R
IN
MAX = 25V
R
1
=
FIGURE 11 - DUAL TRACKING SUPPLY ±1.25V to ±20V
1.25V
1
3mA
= 100 to minimize effect of I
FIGURE 8 - MULTIPLE TRACKING REGULATORS
2
=
(V
= 417 , use 404 , 1%
SG137A/SG137 SERIES
V
REF
OUT
/R
- V
1
) + I
REF
11861 Western Avenue
ADJ
=
(1.25V/100W) + 65mA
1
as high as possible
L
10V - 1.25V
INFINITY Microelectronics Inc.
[phone]
ADJ
Garden Grove, CA 92841
FAX: [phone]
= 704W