AP1601

Step-Up DC/DC Converter

This datasheet contains new product information. Anachip Corp. reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of

this product. No rights under any patent accompany the sale of the product.

Rev. 1.1 Apr. 14, 2005

1/9

Features

-A Guaranteed Start-Up from less than 0.9 V.

-High Efficiency.

-Low Quiescent Current.

-Less Number of External Components needed.

-Low Ripple and Low Noise.

-Space Saving Packages: MSOP-8L and

MSOP-10L.

Applications

-Pagers.

-Cameras.

-Wireless Microphones.

-Pocket Organizers.

-Battery Backup Suppliers.

-Portable Instruments.

General Description

The AP1601 is a high efficiency step-up DC/DC

converter for applications using 1 to 4 NiMH battery

cells. Only three external components are required

to deliver a fixed output voltage of 3.3V or 5V. The

AP1601 starts up from less than 0.9V input with

1mA load. Pulse Frequency Modulation scheme

brings optimized performance for applications with

light output loading and low input voltages. The

output ripple and noise are lower compared with the

circuits operating in PSM mode.

The PFM control circuit operating in 100KHz (max.)

switching

rate

results

in

smaller

passive

components. The space saving MSOP packages

make the AP1601 an ideal choice of DC/DC

converter for space conscious applications, like

pagers,

electronic

cameras,

and

wireless

microphones.

Pin Assignments

1

3

2

4

8

6

7

5

MSOP-8L

FB

LBI

REF

OUT

LX

GND

LBO

SHDN

1

3

2

10

8

9

MSOP-10L

FB

LBI

OUT

LX

GND

47

CLSEL

56

REF

BATT

SHDN

LBO

Pin Descriptions

Name

Description

FB

Use a resistor network to set the output

voltage from +2.0V to +5.5V.

If FB=Vout, Vout=3.3V fix voltage

FB=GND, Vout=5V fix voltage

LBI

Low-Battery Comparator Input. Internally set

to trip at +1.30V.

LBO

Open-Drain Low-Battery Comparator Output.

Connect LBO to OUT through a 100kΩ

LBO

is high impedance during shutdown.

REF

1.2V Reference Voltage. Bypass with a 0.1µF

capacitor.

OUT

Power Output. OUT provides bootstrap power

to the IC.

LX

N-Channel and P-Channel Power MOSFET

Drain

GND Ground

SHDN

shutdown mode. Connect to OUT for normal

operation.

CLSEL

Current-Limit Select Input. CLSEL = OUT sets

the current limit to 0.8A. CLSEL = GND sets

the current limit to 0.4A.

BATT

Battery

Input

and

Damping

Switch

Connection. If damping switch is unused,

leave BATT unconnected.