4

AT9933

Pin Description

Pin Number

Pin

Description

1

VIN

This pin is the input of a 8 - 100V voltage regulator.

2

CS1

These pins are used to sense the input and output currents of the boost-buck converter.

They are the non-inverting inputs of the internal comparators.

7

CS2

3

GND

Ground return for all the internal circuitry. This pin must be electrically connected to the

ground of the power train.

4

GATE

This pin is the output gate driver for an external N-channel power MOSFET.

5

PWMD

When this pin is left open or pulled to GND, the gate driver is disabled. Pulling the pin to

a voltage greater than 2V will enable the gate drive output.

6

VDD

This is a power supply pin for all internal circuits. It must be bypassed to GND with a low

ESR capacitor greater than 0.1µF.

8REF

This pin provides accurate reference voltage. It must be bypassed with a 0.01 - 0.1µF

capacitor to GND.

Block Diagram

Regulator

7.5V

VIN

CS1

CS2

PWMD

GATE

VDD

REF

GND

1.25V

AT9933

Input Comparator

Output Comparator

0mV

100mV