3

Rev:001 Date:11/20/03

SP6649 Ultra-low Quiescent Current, High Efficiency Boost DC-DC Regulator

© Copyright 2002 Sipex Corporation

PIN DESCRIPTION

PIN NUMBER

PIN NAME

DESCRIPTION

Battery Voltage pin. The startup circuitry runs off of this pin. The

operate circuit also uses this voltage to regulate the off-time

0.62V after a successful startup the SP6649 goes into an undervoltage

lockout mode (UVLO).

2

LBI

Low Battery Input pin. LBI below 0.61V causes the LBON pin to pull

down to ground. Use a resistor divider to program the low voltage

threshold for each battery configuration.

3

LBON

current to ground when LBI is below 0.625V.

Resistor Programmable Inductor Peak Current. By connecting a

(for 1.2A).

5

SHDN

to ground to disable all circuitry inside the chip. In shutdown the

output voltage will float down to a diode drop below the battery

potential.

6FB

External Feedback pin. Connect this pin to GND for fixed +3.3V

and GND for adjustable output operation.

7

GND

Ground pin for the internal regulator bias currents.

Switch ground pin. The inductor charging current flows out of this pin.

9LX

Inductor switching node. Connect one terminal of the inductor to the

positive terminal of the battery. Connect the second terminal of the

inductor to this pin. The inductor charging current flows into LX,

through the internal charging N-channel FET, and out the GND pin.

10

Output Voltage pin. The inductor current flows out of this pin during

the off-time. It is also the internal regulator voltage supply, and

minimum off-time one shot input. Kelvin connect this pin to the

positive terminal of the output capacitor.