SG29125A Microsemi Corporation, SG29125A Datasheet - Page 3

• Manufacturer Part Number: SG29125A
• Description: LOW DROPOUT DUAL REGULATOR
• Manufacturer: Microsemi Corporation

12/90 Rev 1.1 2/94
Copyright
ELECTRICAL CHARACTERISTICS
Note 4. The temperature extremes are guaranteed but not 100% production tested.
TYPICAL CIRCUIT WAVEFORM
APPLICATION NOTES
The advantages of using a low-dropout regulator such as the
SG29125/125A are the need for less “headroom” for full regula-
tion, and the inherent reverse polarity protection provided by the
PNP output device. A typical NPN regulator design requires an
input to output differential of approximately two volts minimum.
This is due to the 2Vbe + Vcesat of the NPN Darlington used in
the output, coupled with the voltage drop across the current limit
resistor. In contrast, the “PNP Regulator” uses a single series
pass transistor with its single Vcesat, thus the lower input to
output voltage differential or dropout voltage.
In addition to a low dropout voltage, an important advantage of
the SG29125/125A series is low quiescent current in the standby
mode. When the high current or primary regulator is shut off, the
Standby Output (V
Output Voltage
Line Regulation
Load Regulation
Output Impedance
Quiescent Current
Output Noise Voltage
Long Term Stability
Ripple Rejection
Dropout Voltage
Current Limit
Maximum Operational Input Voltage
1994
CONDITION
VOLTAGE
VOLTAGE
VOLTAGE
STANDBY
PIN 1 (V)
PIN 2 (V)
PIN 5 (V)
SYSTEM
OUTPUT
ON/OFF
SWITCH
(Note 4)
Parameter
INPUT
SB
) Section
0.8V
14V
0V
2V
5V
0V
5V
TURN
ON
12V
60V
DUMP
LOAD
(continued)
6V
6V
1mA
1mA
1mA
I
10Hz - 100kHz
F
I
4.75V
O
O
33V
O
= 120Hz
12V
10mA, V
50mA
DC
V
V
IN
IN
I
I
and 1mA
O
O
LOW V
V
O
26V, I
26V
35mA
50mA
OUT
IN
3.5V
3.7V
6V
4V
OFF
RMS
O
3
, 100Hz - 10kHz
Test Conditions
50mA, -40 C
regulator enters a micropower mode. Here all but the most
essential circuitry to power the standby output is deactivated.
This allows the lowest possible quiescent current (typical around
1.2mA), a vital factor when used in a battery powered system.
In some applications the regulator output voltage is used not only
as a power supply but also as a voltage reference for control
systems. In such cases not just the temperature stability of the
output is important but also the initial accuracy. The SG29125/
125A fills this need as the internal bandgap reference is trimmed
allowing a typical output voltage tolerance of ±1%.
LINE NOISE,
26V
ETC.
12V
CIRCUIT
SHORT
V
T
OUT
A
85 C
5.0V
SHUTDOWN
12V
THERMAL
11861 Western Avenue
4.75
Min.
SG29125/125A
50
60
14V
L
SG29125/125A
INFINITY Microelectronics Inc.
[phone]
0.55
Typ.
12V
300
100
5.0
1.2
10
25
20
66
70
4
1
TURN
OFF
0.8V
Max.
5.25
0.7
0V
50
25
50
3
Garden Grove, CA 92841
mV/1000hr
FAX: [phone]
Units
mV
mV
mV
mA
mA
V
dB
V
V
V
RMS