Contents

1

Block diagram and typical application..............................................3

2

Pin connection and functions ......................................................4

3

Electrical data .....................................................................6

3.1

Absolute maximum ratings....................................................... 6

3.2

Thermal data .................................................................. 6

4

Electrical characteristics...........................................................7

5

Application information ...........................................................10

5.1

Theory of operation............................................................ 10

5.2

OFF-time modulator ........................................................... 12

5.3

High voltage startup ........................................................... 13

5.4

Input line discharge (X-cap discharge function) .................................... 14

5.5

Soft-start..................................................................... 14

5.6

No load operation (burst-mode function) .......................................... 15

5.7

Idle operation (external burst-mode function) ...................................... 15

5.8

Disable operation (DISABLE function) ............................................ 16

5.9

Protections ................................................................... 17

5.9.1

AC brown-in (BI function) ................................................. 17

5.9.2

AC brownout (BO function) ................................................ 18

5.9.3

Output overvoltage (OVP function) .......................................... 18

5.9.4

Overcurrent (OCP1 function)............................................... 18

5.9.5

Inductor saturation detection (OCP2 function).................................. 19

5.9.6

Feedback failure detection ................................................ 19

5.10

Line feedforward .............................................................. 19

6

Package information..............................................................20

6.1

SO-8 package information ...................................................... 20

7

Ordering information .............................................................21

Revision history .......................................................................22

Contents ..............................................................................23

List of tables ..........................................................................25

L4985

Contents

DS13769 - Rev 3

page 23/27