Page No. : 7/12

AVANTICS - AX3842 Series

Specification No.: 050308-FE0008

Application Information

Open Loop Test Circuit

Oscillator and Output Waveforms

Error Amp Configuration

Under Voltage Lockout

4.7K

1K

4.7K

5K

100K

RT

0.1uF

0.1uF

CT

1W

1K

Error Amp.

Adjust

I

Adjust

HPN2222A

COMP

RT/CT

V

Vcc

Output

Ground

Ground

Output

Vcc

Vref

1

2

3

4

5

6

7

8

REF

SENSE

A

AX3842

RT

CT

4

5

6

7

8

5V REG

PWM

Clock

Oscillator

Id

Output

GND

CT

Output

Large RT / Small CT

CT

Output

Small RT / Large CT

Vcc

1

2

3

High peak currents associated with capacitive loads necessitate careful grounding techniques. Timing and

bypass capacitors should be connected close to pin5 in a single point ground. The transistor and 5KΩ

potentiometerare used to samplethe oscillator waveform and apply an adjustable ramp to pin3.

Zi

Zf

V

COMP

2.5V

1mA

1

2

FB

+

-

ON/OFF Command

Von

Voff

AX3842

To Rest Of IC

16V

10V

Icc

<17mA

<0.5mA

Vcc

Voff Von

Vi

7