Preliminary Datasheet
AS1355
3 0 0 m A , Tr i p l e L D O
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.
2 Key Features
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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.
Figure 1. AS1355 - Typical Application Diagram
+5V
VDD1
VOUT1
1µF
VDD2
1µF
VDD3
VOUT3
VOUT2
1µF
1.5V
1µF
REF
C
REF
= 100nF
(Improved Noise Performance)
GND
1.8V
3.3V
AS1355
VDDA
EN1
µP
EN2
EN3
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Revision 0.08
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