DPA423-426

2

K

1/04

Section List

Functional Block Diagram ......................................................................................................................................... 3

Pin Functional Description ........................................................................................................................................ 3

DPA-Switch Family Functional Description .............................................................................................................. 4

CONTROL (C) Pin Operation ................................................................................................................................. 4

Oscillator and Switching Frequency ....................................................................................................................... 5

Pulse Width Modulator & Maximum Duty Cycle ..................................................................................................... 6

Minimum Duty Cycle and Cycle Skipping ............................................................................................................... 6

Error Amplifier ......................................................................................................................................................... 6

On-chip Current Limit with External Programmability ............................................................................................. 6

Line Under-Voltage Detection (UV) ........................................................................................................................ 6

Line Overvoltage Shutdown (OV) ........................................................................................................................... 7

Line Feed Forward with DC

Remote ON/OFF .................................................................................................................................................... 7

Synchronization ...................................................................................................................................................... 8

Soft-Start ................................................................................................................................................................ 8

Shutdown/Auto-Restart .......................................................................................................................................... 8

Hysteretic Over-Temperature Protection ................................................................................................................ 8

Bandgap Reference ................................................................................................................................................ 8

High-Voltage Bias Current Source .......................................................................................................................... 8

Using Feature Pins ...................................................................................................................................................... 9

FREQUENCY (F) Pin Operation ............................................................................................................................. 9

LINE-SENSE (L) Pin Operation .............................................................................................................................. 9

EXTERNAL CURRENT LIMIT (X) Pin Operation ................................................................................................... 9

Typical Uses of FREQUENCY (F) Pin ...................................................................................................................... 12

Typical Uses of LINE-SENSE (L) and EXTERNAL CURRENT LIMIT (X) Pins ....................................................... 12

Application Examples ............................................................................................................................................... 15

Key Application Considerations .............................................................................................................................. 17

DPA-Switch Design Considerations ...................................................................................................................... 17

DPA-Switch Layout Considerations ...................................................................................................................... 18

Quick Design Checklist ......................................................................................................................................... 19

Design Tools ......................................................................................................................................................... 19

Product Specifications and Test Conditions .......................................................................................................... 21

Typical Performance Characteristics ..................................................................................................................... 27

Part Ordering Information ........................................................................................................................................ 31

Package Outlines ...................................................................................................................................................... 32