CS8321 Cherry Semiconductor Corporation, CS8321 Datasheet - Page 2

• Manufacturer Part Number: CS8321
• Description: Micropower 5V/ 150mA Low Dropout Linear Regulator
• Manufacturer: Cherry Semiconductor Corporation

The CS8321 is a series pass voltage regulator. It consists of
an error amplifier, bandgap voltage reference, PNP pass
transistor with antisaturation control, and current limit.
As the voltage at the input, V
ward biased via R. Q
becomes forward biased, the output voltage, V
to rise as Q
Once V
becomes biased and provides the appropriate amount of
base current to Q
output voltage via an internal voltage divider, R1 and R2,
and compares it to the bandgap voltage reference. The
error amplifierÕs output is a current which is equal to the
error amplifierÕs differential input voltage times its
transconductance. Therefore, the error amplifier varies the
base drive current to Q
on the difference between the reference voltage and the
scaled output voltage, V
Output Stage
Output Voltage, V
Dropout Voltage (V
Quiescent Current, (I
Load Regulation
Line Regulation
Ripple Rejection
Current Limit
Short Circuit Output Current
Reverse Current
Electrical Characteristics:
3L D
OUT
PARAMETER
Voltage Reference and Output Circuitry
1
2
3
P
2
rises to a certain level, the error amplifier
PAK
Õs output current charges the output capacitor.
PACKAGE LEAD #
P
. The error amplifier monitors the scaled
OUT
N
IN
provides base drive for Q
N
Q
-V
3L TO-220
OUT
, which provides bias to Q
)
OUT
.
1
2
3
IN
)
, is increased, Q
6V < V
9V < V
100µA ² I
I
I
I
I
I
V
6V < V < 26V, I
7 Ð V
f = 120Hz
V
V
OUT
OUT
OUT
OUT
OUT
IN
OUT
OUT
IN <
= 14V, 100µA < I
Circuit Description and Application Notes
= 150mA, -40¡C ² T
= 150mA, T
= 1mA @ V
< 150mA @ V
< 50mA @ V
IN
= 5V, V
= 0V
IN
TEST CONDITIONS
26V, I
Ð 17V, I
LEAD SYMBOL
< 16V,
OUT
OUT
N
OUT
V
Gnd
V
IN
Package Lead Description
² 150mA
P
IN
OUT
is for-
OUT
. As Q
OUT
= 0V
, begins
=1mA, -40¡C ² T
IN
P
A
, based
IN
= 125¡C
IN
= 13V
= 150mA,
= 1mA
= 13V
= 13V
OUT
P
A
< 150mA
2
² 85¡C
Input Voltage
Ground. All Gnd leads must be connected to Ground.
5V, ±2%, 150mA Output.
An antisaturation control circuit has also been added to
prevent the pass transistor from going into deep satura-
tion, which would cause excessive power dissipation due
to large bias currents lost to the substrate via a parasitic
PNP transistor, as shown in Figure 1.
Figure 1. The parasitic PNP transistor which is part of the pass transis-
tor (Q
A
² 125¡C, -40¡C ² T
P
) structure.
MIN
4.90
175
Q
60
60
Parasitic
Antisaturation Protection
Substrate
FUNCTION
J
² 150¡C unless otherwise specified.
5.00
250
200
140
TYP
0.3
15
75
4
5
5
Q
P
V
5.10
200
200
MAX
0.5
0.6
V
OUT
25
50
50
6
IN
UNIT
mA
mA
mV
mV
mA
mA
µA
µA
dB
V
V
V