SG29055 Datasheet, PDF (1/4 Pages) Microsemi Corporation – LOW DROPOUT DUAL REGULATOR

SG29055/55A
LOW DROPOUT DUAL REGULATOR
DESCRIPTION
The SG29055/55A is a dual 5V/5V positive voltage regulator. One output is a high
current (up to 1000 mA) regulator that can be turned on or off by a high impedance low
current TTL compatible switch. The second or standby output remains on regardless.
The on/off switch not only shuts off the high current output but actually puts the IC in
a micropower mode making possible a low quiescent current. This unique character-
istic coupled with an extremely low dropout, (.55V for output current of 10mA) makes
the SG29055/55A well suited for power systems that require standby memory. The
SG29055/55A includes other features which were originally designed for automotive
applications. These include protection from reverse battery installations and double
battery jumps. The high current regulator has overvoltage shutdown to protect both
the internal circuitry and the load during line transients, such as load dump (60V). In
addition, the high current regulator design also has built-in protection for short circuit
and thermal overload. During these fault conditions of the primary regulator the
standby regulator will continue to power its load.
The SG29055 is the 5 volt, ±5% version of a family of dual regulators with a standby
output voltage of 5V. Other high current outputs of 8.2V and 12V are available Also
available is the SG29055A which offers an improved output voltage tolerance of ±2%.
They are available in the plastic TO-220 power package and are designed to function
over the automotive ambient temperature range of -40°C to 85°C.
FEATURES
• 2% Internally Trimmed Output
• Two regulated outputs
• Output current in excess of
1000mA
• Low quiescent current standby
regulator
• Input-output differential less than
0.6V at 0.5A
• Reverse battery protection
• 60V load dump protection
• -50V reverse transient protection
• Short circuit protection
• Internal thermal overload protec-
tion
• Available in plastic TO-220
• ON/OFF switch for high current
output
TYPICAL APPLICATION CIRCUIT
INPUT VOLTAGE
C1 *
0.1µF
1
SG29055/55A
OVERVOLTAGE
THERMAL
SHUTDOWN
* Required if regulator is located far from power
supply filter.
** Required for stability. May be increased without
bound. Capacitor must be rated to operate at the
minimum temperature expected for the regulator
system.
2
OUTPUT VOLTAGE
(5V, 1000mA)
C2**
10µF
ON/OFF SWITCH
4
(for output voltage only)
REGULATOR
BIAS
1.23V
REFERENCE
5V STANDBY
REGULATOR
3
5
5.6V
STANDBY OUTPUT
(5V, 50mA)
C3**
10µF
12/90 Rev 1.1 2/94
Copyright © 1994
GROUND
1
LINFINITY Microelectronics Inc.
11861 Western Avenue ∞ Garden Grove, CA 92841
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