2

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNIT

PACKAGE LEAD #

LEAD SYMBOL

FUNCTION

Circuit Description and Application Notes

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.

becomes biased and provides the appropriate amount of

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

on the difference between the reference voltage and the

Antisaturation Protection

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-

Substrate

Voltage Reference and Output Circuitry

Package Lead Description

s Output Stage

4.90

5.00

5.10

V

0.3

0.5

V

0.6

V

200

µA

4

6

mA

15

25

mA

Load Regulation

5

50

mV

Line Regulation

5

50

mV

Ripple Rejection

60

75

dB

f = 120Hz

Current Limit

175

250

mA

Short Circuit Output Current

60

200

mA

Reverse Current

140

200

µA

3L TO-220

11

Input Voltage

2

2

Gnd

Ground. All Gnd leads must be connected to Ground.

33

5V, ±2%, 150mA Output.