* All voltages are with respect to pin 5, all currents are positive into the specified terminal.

PIN CONNECTION (top view)

COMP

GROUND

OUTPUT

Vi

1

3

2

4

6

5

7

8

D95IN332

Minidip/SO8

ORDERING NUMBERS

SO8

Minidip

UC3842TD

UC3843TD

UC3844TD

UC3845TD

UC3842TN

UC3843TN

UC3844TN

UC3845TN

ABSOLUTE MAXIMUM RATINGS

Symbol

Parameter

Value

Unit

Supply Voltage (low impedance source)

30

V

Supply Voltage (Ii < 30mA)

Self Limiting

Output Current

±1

A

Output Energy (capacitive load)

5

µJ

Analog Inputs (pins 2, 3)

– 0.3 to 5.5

V

Error Amplifier Output Sink Current

10

mA

≤ 25 °C (Minidip)

1.25

W

Power Dissipation at Tamb

≤ 25 °C (SO8)

800

mW

Storage Temperature Range

– 65 to 150

°C

Lead Temperature (soldering 10s)

300

°C

PIN FUNCTIONS

No

Function

Description

1

COMP

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

5

GROUND

This pin is the combined control circuitry and power ground.

6

OUTPUT

This output directly drives the gate of a power MOSFET. Peak currents up to 1A are sourced

and sunk by this pin.

This pin is the positive supply of the control IC.

UC3842T - UC3843T - UC3844T - UC3845T

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