Step-Up/Down DC-DC Converter

in QSOP Package

_______________________________________________________________________________________

5

______________________________________________________________Pin Description

NAME

FUNCTION

1

LX

Inductor Connection to the Drain of the Internal N-Channel Power MOSFET

PIN

Typical Operating Characteristics (continued)

A

B

10

µs/div

OUTPUT RIPPLE (HEAVY LOAD)

MAX1672-13

A

B

50

µs/div

STARTUP DELAY

MAX1672-14

A

B

200

µs/div

TURN-OFF DELAY

MAX1672-15

2

PGND

Power Ground

3

ONB

On Control Input. When ONB = low or ONA = high, the IC is on. Connect ONB to GND for normal operation

(Table 1).

4

ONA

On Control Input. When ONA = low and ONB = high, the IC is off. Connect ONA to PS for normal operation

(Table 1).

5

3/5

the state of the 3/5 pin is ignored (Table 2).

6

PGI

Low-Battery Detector Input (1.25V threshold)

7

PGO

8

ILIM

Inductor-Current-Limit Selection Input. Connect to PS for 0.8A current limit and to GND for 0.5A current limit.

9

OUT

Regulator Output. Drain of internal PFET linear regulator. Bypass with a 4.7µF capacitor to GND.

10

FB

Feedback Input. For 3.3V or 5V output, connect to GND. For adjustable output, connect to feedback resistor-

11

PS

Bootstrapped Power Supply. Output of step-up switch-mode regulator and source of internal PFET linear

regulator. The IC is powered from this pin.

12

IN

Input Voltage Sense Input. Connect to input supply.

13

REF

Reference Voltage Output. Bypass with a 0.1µF capacitor to GND.

14

GND

Analog Ground

15

PGND

Power Ground

16

LX

Inductor Connection to the Drain of the Internal N-Channel Power MOSFET