UC3842B, UC3843B, UC2842B, UC2843B, NCV3843BV
PIN FUNCTION DESCRIPTION
Pin
8–Pin
1
2
3
4
14–Pin
1
3
5
7
Function
Compensation
Voltage
Feedback
Current
Sense
R
T
/C
T
Description
This pin is the Error Amplifier output and is made available for loop compensation.
This is 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
connecting resistor R
T
to V
ref
and capacitor C
T
to ground. Operation to 500 kHz
is possible.
This pin is 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.
This pin is the positive supply of the control IC.
This is the reference output. It provides charging current for capacitor C
T
through resistor R
T
.
This pin is a separate power ground return that is connected back to the power source. It is
used to reduce the effects of switching transient noise on the control circuitry.
The Output high state (V
OH
) is set by the voltage applied to this pin. With a separate
power source connection, it can reduce the effects of switching transient noise on the
control circuitry.
This pin is the control circuitry ground return and is connected back to the power
source ground.
No connection. These pins are not internally connected.
5
6
7
8
10
12
14
8
11
Gnd
Output
V
CC
V
ref
Power
Ground
V
C
9
2,4,6,13
Gnd
NC
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