LX1570/1571

PRODUCT DA T ABOOK 1996/1997

Copyright © 1997

Rev. 0.9.3

1/97

2

ABSOLUTE MAXIMUM RATINGS

(Note 1)

Supply Voltage (V

Digital Inputs ....................................................................................................... -0.3 to 7V

Output Peak Current Source (500nS) ........................................................................... 1A

Output Peak Current Sink (500nS) ................................................................................ 1A

PACKAGE PIN OUTS

C

T

V

CC

OUT DRV

GND

S.S.

V

FB

COMP

C.S.

1

8

27

36

45

M & Y PACKAGE

(Top View)

DM PACKAGE

(Top View)

C

T

V

CC

OUT DRV

GND

S.S.

V

FB

COMP

C.S.

1

8

27

36

45

Note 1. Exceeding these ratings could cause damage to the device. All voltages are with respect

to Ground. Currents are positive into, negative out of the specified terminal.

LX1571 BLOCK DIAGRAM

THERMAL DATA

M PACKAGE:

THERMAL RESISTANCE-JUNCTION TO AMBIENT,

θθθθθ

JA

95°C/W

DM PACKAGE:

THERMAL RESISTANCE-JUNCTION TO AMBIENT,

θθθθθ

JA

165°C/W

Y PACKAGE:

THERMAL RESISTANCE-JUNCTION TO AMBIENT,

θθθθθ

JA

130°C/W

Junction Temperature Calculation:

T

J

= T

A

+ (P

D

x

θ

JA

).

The

θ

JA

numbers are guidelines for the thermal performance of the device/pc-board system.

All of the above assume no ambient airflow.

Error Amp

Voltage Hiccup

Comp.

2.5V

Minimum

Current Comp

C.S. Comp

Current Mode

Hiccup Comp

R

S

Q

PWM Latch

7

6

V

CC

OUT DRV

6V

R

S

Q

Q

Hiccup

Latch

2R

R

Internal

Bias

2.5V

REF

1V

5V

2.5V

16V

1.5V

0.25V

0.5V

4

3

2

1

S.S.

V

FB

COMP

C.S.

8

C

T

Voltage Mode Hiccup

Timing / Duty Cycle

Control

CHG

CONTROL

QUICK

CHG

CONTROL

LATCH RESET

CONTROL

LATCH

SET CONTROL

VALLEY

THRESHOLD

CONTROL

DISCH

CONTROL