AS1337

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

www.austriamicrosystems.com/DC-DC_Step-Up/AS1337

Revision 1.05

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Data sheet

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. Compact size and minimum external parts

requirements 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.

In the shutdown mode of the AS1337B the battery is discon-

nected and the output is discharged.

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 diagnostic equipment, hand-

held instruments, pagers, digital cameras, remote wireless

transmitters, MP3 players, LCD bias supplies, cordless

phones, GPS receivers, and PC cards.

Table 1. Standard Products

Model

Operation Mode

AS1337A

Battery Connected in Shutdown

AS1337B

Battery Disconnected in Shutdown and

Output Discharged

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