CS8129
CS8129
5V, 750mA Low Dropout Linear
Regulator with Lower RESET Threshold
Description
The CS8129 is a precision 5V linear reg-
ulator capable of sourcing 750mA.
The
RESET
threshold voltage has been
lowered to 4.2V so that the regulator
can be used with 4V microprocessors.
The lower
RESET
threshold also per-
mits operation under low battery condi-
tions (5.5V plus a diode). The
RESET
Õs
delay time is externally programmed
using a discrete RC network. During
power up, or when the output goes out
of regulation,
RESET
remains in the
low state for the duration of the delay.
This function is independent of the
input voltage and will function correct-
ly as long as the output voltage remains
at or above 1V. Hysteresis is included in
the Delay and the
RESET
comparators
to improve noise immunity. A latching
discharge circuit is used to discharge
the delay capacitor when it is triggered
by a brief fault condition.
The regulator is protected against a
variety of fault conditions: i.e. reverse
battery, overvoltage, short circuit and
thermal runaway conditions. The regu-
lator is protected against voltage tran-
sients ranging from -50V to +40V. Short
circuit current is limited to 1.2A (typ).
The CS8129 is packaged in a 5 lead
TOÐ220 and a 16 lead surface mount
package.
Features
s
5V +/- 3% Regulated
Output
s
Low Dropout Voltage
(0.6V @ 0.5A)
s
750mA Output Current
Capability
s
Reduced RESET Threshold
for use with 4V Micro-
processors
s
Externally Programmed
RESET Delay
s
Fault Protection
Reverse Battery
60V, -50V Peak Transient
Voltage
Short Circuit
Thermal Shutdown
Block Diagram
V
IN
Over Voltage
Shutdown
V
OUT
Pre-
Regulator
Regulated Supply
for Circuit Bias
Bandgap
Reference
Charge
Current
Generator
Thermal
Shutdown
Package Options
16 Lead SOIC Wide
V
IN
NC
1
V
OUT
NC
V
OUT(SENSE)
Gnd
Gnd
Gnd
NC
NC
Error
Amplifier
Anti-Saturation
and
Current Limit
V
OUTSENSE
+
-
-
+
+
-
NC
Gnd
Gnd
RESET
NC
Latching Discharge
Delay
Q
+
-
S
R
Delay
5 Lead TO-220
V
DISCHARGE
Delay Comparator
RESET
Gnd
1
1 V
IN
2 RESET
3 Gnd
4 Delay
5 V
OUT
Cherry Semiconductor Corporation
2000 South County Trail, East Greenwich, RI 02818
Tel: (401)885-3600 Fax: (401)885-5786
Email: info@cherry-semi.com
Web Site: www.cherry-semi.com
Rev. 3/31/99
1
A
¨
Company
CHERRY [ CHERRY SEMICONDUCTOR CORPORATION ]
