5

Block Diagram

Q

SS

COMP

LGnd

PGnd

-

+

5 BIT

DAC

Slow Feedback

Maximum

On-Time

Timeout

R

Q

S

COFF

One Shot

PWM

COMP

SS High

Comparator

FAULT

Latch

2.5V

Error

Amplifier

Fast Feedback

-

+

Comparator

-

+

-

+

-

+

-

+

VFFB Low

Comparator

PWM

Comparator

SS Low

Comparator

R

Q

S

Q

R

Q

S

2µA

5V

60µA

Normal

Off-Time

Timeout

Extended

Off-Time

Timeout

Time Out

Timer

(30µs)

Edge Triggered

Off-Time

Timeout

3.90V

3.85V

FAULT

FAULT

GATE = ON

GATE = OFF

PWM

Latch

1V

0.7V

Package Pin Description: continued

PACKAGE PIN #

PIN SYMBOL

FUNCTION

16L SO Narrow & PDIP

11

PGnd

High current ground for the IC. The MOSFET driver is referenced to

this pin. Input capacitor ground and the anode of the Schottky diode

should be tied to this pin.

12

NC

No connection.

13

Input power for the IC.

14

LGnd

Signal ground for the IC. All control circuits are referenced to this pin.

15

COMP

Error amplifier compensation pin. A capacitor to ground should be

provided externally to compensate the amplifier.

16

Error amplifier DC feedback input. This is the master voltage feedback

which sets the output voltage. This pin can be connected directly to the

output or a remote sense trace.