4

Date: 5/25/04

© Copyright 2004 Sipex Corporation

PIN DESCRIPTION

NAME

FUNCTION

PIN NUMBER

1

N/C

No Connection

2

ENABLE

TTL compatible input with internal 4uA pullup. Floating or Venable> 1.5V will

enable the part, Venable < 0.65V disables part.

3

ISP

Current Sense Positive Input: Rail to Rail Input for Over-Current Detection,

43mV threshold with 10µs (typ) response time.

4

ISN

Current Sense Negative Input: Rail to Rail input for Over-Current Detection.

Feedback Voltage Pin: Inverting input of the error amplifier and serves as the

output voltage feedback point for the buck converter. The output voltage is

sensed and can be adjusted through an external resistor divider.

6

COMP

Error Amplifier Compensation Pin: A lead lag network is typically connected

to this pin to compensate the feedback loop. This pin is clamped by the SS

voltage and is limited to 2.8V maximum.

7SS

Soft Start Programming Pin: This pin sources 50µA on start-up. A 0.01µF to

1µF capacitor on this pin is typically enough capacitance to soft start a power

supply. In addition, hiccup mode timing is controlled by this pin through the

5µA discharge current. The SS voltage is clamped to 2.7V maximum.

Frequency Programming Pin: A resistor to ground is used to program

frequency. Typical values - 18,700Ω, 300kHz; 10,200Ω, 500kHz.

9

PROG

Programming Pin:

PROG = GND; MODE = NFET/CONTINOUS

PROG = 68kΩ to GND; MODE = NFET/DISCONTINOUS

PROG = VCC; MODE = PFET/CONTINOUS

PROG = 68kΩ to VCC; MODE = PFET/DISCONTINOUS

10

I.C. Supply Pin: ESD structures also hooked to this pin. Properly bypass this

pin to PGND with a low ESL/ESR ceramic capacitor.

11

GL

Synchronous FET Driver: 1nF/20ns typical drive capability.

12

PGND

Power Ground Pin: Used for Power Stage. Connect Directly to GND at I.C.

pins for optimal performance.

13

GND

Ground Pin: Main ground pin for I.C.

14

SWN

Switch Node Reference: High side MOSFET driver reference. Can also be

tied to GND for low voltage applications.

15

GH

HIgh Side MOSFET Driver: Can be NFET or PFET depending on Program

Mode. 1nF/20ns typical drive capability. Maximum voltage rating is

referenced to SWN.

16

BST

is forced to turn on for at least 300ns. This is intended for enough time to

charge the BST capacitor.