AS1326

High Current, 0.8A DC-DC Step-Up Converters

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Revision 1.05

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Datasheet

1 General Description

The AS1326A/AS1326B are high-efficiency, high cur-

rent, DC-DC step-up converters specifically designed for

battery-powered wireless applications. Low quiescent

supply current (65µA), high operating frequency (1MHz),

and minimal external component requirements make

these devices perfect for small hand-held applications.

Both devices use synchronous-rectified pulse-width

modulation (PWM) boost technology to generate 2.5 to

5.0V outputs from a wide range of inputs, such as 1 to 3

alkaline/NiCd/NiMH cells or a single lithium-ion (Li+)

cell. Automatic powersave operation significantly

improves efficiency at light-loads.

Continuous switching mode is available for applications

requiring constant-frequency operation at all load cur-

rents. PWM operation can also be synchronized to an

external clock to protect sensitive frequency bands in

communications equipment.

Analog soft-start and adjustable current limit permit opti-

mization of rush in current and external component size.

The AS1326A/AS1326B are available in a 10-pin TDFN

(3.0mm x 3.0mm) package.

Figure 1. AS1326 - Block Diagram

2 Key Features

!

Up to 800mA Output

!

Constant-Frequency (1MHz) Operation

!

Up to 96% Efficiency

!

Input Range: 0.7 to 5.0V

!

Fixed Output: 3.3V

!

Adjustable Output: 2.5 to 5.0V

!

PWM Synchronous-Rectified Technology

!

Logic-Controlled Shutdown: 0.1µA

!

Synchronizable Switching Frequency

(0.5 to 1.2MHz)

!

Adjustable Current Limit

!

Adjustable Soft-Start

!

10-pin TDFN (3.0mm x 3.0mm) Package

3 Applications

The devices are ideal for digital cordless phones. mobile

phones, wireless handsets, hand-held instruments,

PDAs, two-way pagers, and any battery-operated equip-

ment.

Table 1. Standard Products

Model

Input Signal Activation

AS1326A

Logic-Low On

AS1326B

Logic-High On

AS1326

+

–

Reference

Startup

Osc

Controller

On

Ref

GND

Rdy

1MHz Osc

En

CLK/SEL Mode

Osc

On

Q

D

En

Osc

Mode

FB

ISET

2.15V

IC Power

Undervoltage

Lockout

9

POUT

8

LX

7

PGND

2

REF

3

GND

6

CLK/SEL

4

FB

1

ISET

5

OUT

10

ON

10

ONN

1.25V

AS1326A

only

AS1326B

only