AS1355

300mA, Tr iple LDO

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Revision 0.08

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Preliminary Datasheet

1 General Description

The AS1355 is a high-performance triple CMOS low-

dropout voltage regulator in a single QFN package. The

efficient set of programmable power supplies is opti-

mized to deliver the best compromise between quies-

cent current and regulator performance for mobile

phones, PDAs, MP3 players, and other battery powered

devices.

Stability is guaranteed with ceramic output capacitors of

only 1µF (±20% – X5R) up to 4.7µF (±20% – X5R). The

low equivalent series resistance (ESR) of these capaci-

tors ensures low output impedance at high frequencies.

Regulation performance is excellent even under low

dropout conditions, when the power transistor has to

operate in linear mode.

The low-noise performance allows direct connection of

noise sensitive circuits without additional filtering net-

works.

The AS1355 is available in a 16-pin QFN 3x3 package.

Figure 1. AS1355 - Typical Application Diagram

2 Key Features

!

3 Independent Voltage Regulators with Shutdown

!

Output Current: 300mA each LDO

!

Programmable Output Voltage Range: 1.25V to

3.6V in 50mV Steps

!

Accuracy: ±1.0%

!

PSRR: 70dB at 1kHz, 60dB at 100kHz

!

Line Regulation: ±2mV

!

Load Regulation: ±0.6mV

!

Supply Range: 2.3V to 5.5V

!

0.1V Dropout Voltage @ Iload = 200mA

!

Shutdown Current:

≤1µA

!

Supply Current Without Load: 160µA (typ)

!

Softstart for Low Inrush Current

!

Stable with low ESR Ceramic Capacitors from 1µF

to 4.7µF

!

Low Noise: 40µV rms @10Hz to 100kHz Bandwidth

!

Thermal Protection

!

Over-Current Protection

!

Temperature Range: -40°C to +85°C

!

16-pin QFN 3x3 Package

3 Applications

The AS1355 is ideal for cordless and mobile phones,

MP3 players, CD and DVD players, PDAs, hand-held

computers, digital cameras, and any other hand-held

battery-powered device.

1µF

3.3V

(Improved Noise Performance)

µP

AS1355

VOUT1

VDD1

EN1

EN2

EN3

GND

REF

+5V

1µF

VDD2

VDD3

1µF

1.8V

VOUT2

1µF

1.5V

VOUT3

VDDA