Data Sheet
CURRENT MODE PWM CONTROLLER
Pin Configuration
AP384XC
P/M Package
(DIP-8/SOIC-8)
COMP
V
FB
I
SENSE
R
T
/C
T
1
2
3
4
8
7
6
5
V
REF
V
CC
OUTPUT
GND
Figure 2. Pin Configuration of AP3842C/3C/4C/5C (Top View)
Pin Description
Pin Number
1
2
3
4
Pin Name
COMP
V
FB
I
SENSE
R
T
/C
T
Function
This pin is the Error Amplifier output and is made available for loop compensation.
The inverting input of the Error Amplifier. It is normally connected to the switching
power supply output through a resistor divider.
A voltage proportional to inductor current is connected to this input. The PWM uses
this information to terminate the output switch conduction.
The Oscillator frequency and maximum output duty cycle are programmed by con-
necting resistor R
T
to V
REF
and capacitor C
T
to ground. Operation to 500 kHz is possi-
ble.
The combined control circuitry and power ground.
This output directly drives the gate of a power MOSFET. Peak currents up to 1.0 A are
sourced and sunk by this pin.
The positive supply of the control IC.
This is the reference output. It provides charging current for capacitor C
T
through
resistor R
T
.
5
6
7
8
GND
OUTPUT
V
CC
V
REF
Sep. 2006 Rev. 1. 1
BCD Semiconductor Manufacturing Limited
2
BCDSEMI [ BCD SEMICONDUCTOR MANUFACTURING LIMITED ]
