AS1337

200mA, DC-DC Step-Up Converter with Buck Mode

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Revision 1.03

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Datasheet

1 General Description

The AS1337 is a synchronous, fixed frequency,

highefficiency DC-DC boost converter capable of

supplying 3.3V @ 200mA from two AA Cells. Com-

pact size and minimum external parts require-

ments make these devices perfect for modern

portable devices. The AS1337 offers automatic

powersave mode to increase efficiency at light

loads. For input voltages higher than VOUT the

AS1337 will switch in a step down mode, so that a

Buck Boost function is realized.

The AS1337A offers a shutdown mode where the

battery is connected directly to the output enabling

the supply of real-time-clocks or memories.

The AS1337 offers a POK (open-drain) feature

which detects output power fail of 10%.

2 Key Features

!

Input Voltage Range: 0.65V to 4.5V

!

Low Start-Up Voltage: 0.85V

!

Output Voltage Range: 2.5V to 5.0V

!

Delivers 200mA @ 3.3V (from two AA Cell)

!

up to 97% Efficiency

!

High-Speed Fixed-Frequency: 1.2MHz

!

Single-Cell Operation

!

Internal PMOS Synchronous Rectifier

!

Automatic Powersave Operation

!

Anti-Ringing Control Minimizes EMI

!

Logic Controlled Shutdown (< 1µA)

!

TDFN (3x3mm) 8-pin Package

3 Applications

The AS1337 is ideal for low-power applications

where ultra-small size is critical as in medical diag-

nostic equipment, hand-held instruments, pagers,

digital cameras, remote wireless transmitters, MP3

players, LCD bias supplies, cordless phones, GPS

receivers, and PC cards.

1.6V to 3.6V

Figure 1. AS1337 - Typical Application Diagram – Dual Cell to 3.3V Synchronous Boost Converter

3.6V

1.6V

Buck Mode

Boost Mode

AS1337

22µF

L1

4.7µH

GND

FB

VIN

EN

PGND

POK

LX

VOUT

On

Off

10µF