Microsemi

Linfinity Microelectronics Division

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

Page 2

Copyright

 2000

Rev. 1.0, 2001-09-19

LX1684

Voltage-Mode PWM Controller

L I N F IN IT Y

D I V I S I O N

ABSOLUT E M AXI M U M RA T

ABSOLUT E M AXI M U M RA T

ABSOLUT E M AXI M U M RA T

ABSOL UT E M AXI M U M RA T I NGS (NOTE 1 )

INGS (NOTE 1 )

INGS (NOTE 1 )

INGS (NOTE 1 )

Input Voltage (CSP Pin).................................................................................. 14V

Output Drive Peak Current Source (500ns).................................................... 1.0A

Output Drive Peak Current Sink (500ns)........................................................ 1.0A

Input Voltage (SS/ENABLE Pin)...........................................................-0.3 to 6V

Operating Junction Temperature ..................................................................150°C

Storage Temperature ...................................................................-65°C to +150°C

Lead Temperature (Soldering 10 Seconds) ..................................................300°C

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

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

PACKAGE PIN OUT

PACKAGE PIN OUT

PACKAGE PIN OUT

PACKAGE PIN OUT

1

2

4

3

14

13

11

12

(T op View)

5

6

10

7

9

8

TDRV

N/C

V

C1

N/C

CS

N/C

V

CC

FB

N/C

SS

VCSP

GND

PG ND

BDRV

THERMA L D A TA

THERMA L D A TA

THERMA L D A TA

THERMA L D A TA

D

THERMAL RESISTANCE

θθθθ

JA

165

°°°°C/W

The

system. All of the above assume no ambient airflow.

FU N

FU N

FU N

F U N C TIONA L P I N D ESCRIP T

CTIONA L P I N D ESCRIP T

CTIONA L P I N D ESCRIP T

CTIONA L P I N D ESCRIP T ION

ION

ION

ION

Voltage Feedback. A 1.25V reference is connected to a resistor divider to set desired output voltage.

SS

Soft-Start And Hiccup Capacitor Pin. During start up the voltage of this pin controls the output voltage. An

internal 22k

Ω resistor and the external capacitor set the time constant for soft-startup. Soft-start does not begin

until the supply voltage exceeds the UVLO threshold. When over-current occurs, this capacitor is used for timing

hiccup. The PWM can be disabled by pulling the SS pin below 0.3V

VCSP

Positive Over-Current Threshold Input

GND

Analog ground for SS, FB, CS and VCC.

PGND

MOSFET driver power ground

TDRV

Gate Drive For Upper MOSFET.

BDRV

Gate Drive For Lower MOSFET.

Separate Supply For MOSFET Gate Drives. Connect to gate drive voltage.

CS

Over-Current Set. Connect resistor between CS pin and the source of the upper MOSFET to set current-limit

point.

IC Supply Voltage (nominal 5V).