AS1351
Programmable Dual LDO
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Data Sheet
1 General Description
The AS1351 is a high-performance dual CMOS low-
dropout voltage regulator in a single 3x3mm 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.
The one-time-programmable (OTP) function provides
greater design flexibility by allowing for independent pro-
gramming of the output voltage for each regulator on-
site. The OTP function allows for fast prototyping reduc-
ing development times and costs significant. Factory
trimmed versions for full-production are also available.
St ability 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 di rect connection of
noise sensitive circuits with out additional filtering net-
works.
The AS1351 is available in a 12-p in QFN 3x3mm pack-
age.
Figure 1. Pinout Assignments (Top View)
2 Key Features
! 2 Independent Voltage Regulators with Shutdown
! Output Current: 200mA each LDO
! One Time Programmable Output Voltage
(User- or Factory-Trimmed)
! Programmable Output V oltage Range: 1.8 to 3.3V in
0.1V Steps
! Accuracy: ±1.5%
! PSRR: 70dB at 1kHz, 40dB at 100kHz
! Line Regulation: ±2mV
! Load Regulation: ±0.6mV
! Supply Range: 3 to 5.5 V
! 0.2V Dropout Voltage @ I = 200mA
! Shutdown Current: ≤1µA
! Supply Current Without Load: 125µA (typ)
! Softstart for Low Inrush Current
! Stable with low ESR Ceramic Capacitors from 1 to
4.7µF
! Low Noise: 40µV rms @10Hz to 100kHz Bandwidth
! Thermal Protection
! Over-Current Protection
! Temperature Range: -40 to +85°C
! 12-pin QFN 3x3mm Package
3 Applications
The AS1351 is ideal for cordless and mobile phones,
MP3 players, CD and DVD players, PDAs, handheld
computers, digital cameras, and any other hand-held
battery-powered device.
AS1351
VDD
VOUT2VOUT1
GND
EN2
EN1
N/C N/C REF
101112
654
1
2
3
9
8
7
VDD
N/C
GND
GND (Exposed Pad)
13
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AS1351
Data Sheet - Pinout
4 Pinout
Pin Descriptions
Figure 2. Pin Assignments (Top View – Not To Scale)
† All GND pins (3, 4, and 13) must be connected together externally.
Table 1. Pin Descriptions
Number Name Description
1 EN2 Digital input to enable VOUT2.
2 EN1 Digital input to enable VOUT1.
3GND Negative supply voltage. †
4GND Negative supply voltage. †
5V
OUT1 Regulated analog outp ut vol tage 1.
6V
OUT2 Regulated analog outp ut vol tage 2.
7VDD Positive supply voltage. Pins 7 and 9 must be connected together externally.
8 N/C Not connected.
9V
DD Positive supply voltage. Pins 7 and 9 must be connected together externally.
10 REF Analog reference voltage; connect to 100nF capacitor during normal operation.
11 N/C Not connected.
12 N/C Not connected.
13 GND Negative supply voltage; this pin is the exposed pad. †
AS1351
VDD
GND
EN2
EN1
N/C N/C REF
101112
654
1
2
3
9
8
7
VDD
N/C
GND (Exposed Pad)
13
VOUT2VOUT1GND
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AS1351
Data Sheet - Absolute Maximum Ratings
5 Absolute Maximum Ratings
Stresses beyond those li sted in Tab l e 2 ma y caus e pe rmanent damage to the device. These are stress ratings only,
and functional operation of the device at these or any othe r conditions beyond those indicated in the operational sec-
tions of the specifications is no t implied. Exposure to absolute maximum rating conditions for extended periods may
affect device reliability.
Table 2. Absolute Maximum Ratings
Parameter Min Max Units Comments
VDD to GND -0.3 7 V
Any other pin to GND -0.3 VDD + 0.3 V
Continuous Power Dissipation
QFN12 3x3mm 590 1500 mW Min value measured at TAMB = 85°C;
max value measure d at TAMB = 25°C.
Package-Body Peak
T emperature 260 °C
The reflow peak soldering temperature (body
temperature) specified is in accordance with
IPC/JEDEC J-STD-020C “Moisture/Refl ow
Sensitivity Classifi cation for non-hermetic
Solid State Surface Mount Devices”.
Operating Ambient
Temperature -40 85 °C
Storage Temperature -65 150 °C
Electrostatic Discharge
Protection (ESD) Level 1kVHBM – Norm: MIL 883 E method 3015.
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AS1351
Data Sheet - Electrical Characteristics
6 Electrical Characteristics
VDD = 4V; TAMB = -40 to +85 °C (Typ values are for TAMB = 25°C); CLOAD = 1µF (Ceramic); unless otherwise specified.
Notes:
1. Guaranteed by design and verified by lab evaluation.
2. Startup is performed if any EN pin goes high.
Table 3. Electrical Characteristics
Symbol Parameter Conditions Min Typ Max Unit
VDD Supply Voltage Range 3 5.5 V
VOUT Output Voltage Range 1.8 3.3 V
RON On Resistance 1 Ω
PSRR 1Power Supply
Rejection Ratio f = 1kHz, CREF = 100nF 70 dB
f = 100kHz, CREF = 100nF 40
IOFF Shut Down Current ENx = Low 1 µA
IVDD Supply Current Without Load 125 200 µA
tset 1Output Voltage
Settling T ime ILOAD Switched from 0 to 100mA 50 µs
tstart 1Start-Up Time 2CREF = 100nF Pre-charged 300 µs
CREF = 0nF Uncharged 300 µs
CREF = 100nF Uncharged 15 ms
VOUT Output Voltage Tolerance ILOAD = 0mA, TAMB = 25°C -1.5 1.5 %
ILOAD = 0 to 200mA -2 2 % 1
VLINEREG Line Regulation, Static VDD = 5.5V -1 1 %
VDD = 3 to 4.5V -2 2 mV 1
VLOADREG Load Regulation, Static ILOAD = 0 to 50 mA 0.3 2.5 mV 1
ILOAD = 0 to 200 mA
(referenced to 100mA) 0.6 5 mV 1
VIH Enable Input Vol tage High 0.6 x VDD V
VIL Enable Input Voltage Low 0.8 V
ILOAD Output Current 0 200 mA
ILIMIT Output Current Limitation 400 mA
VNoise Output Noise Vo ltage 10 to 100kHz, CREF = 100nF 40 µVRMS
Thermal Protection 145 °C
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AS1351
Data Sheet - Typical Ap plication
7 Typical Application
Figure 3. Typical AS1351_ux Application
One-Time Programming Procedure Output Voltages
The two LDOs can be programmed and burned to any output voltage between 1.8V and 3.3V in steps of 0.1V. Custom-
ers can burn the desired output voltages onsite using the austriamicrosystems programming board.
Furthermore, th e AS1351 is availab le in pre-program med versions with fixed output voltages (see Ordering Information
on page 9.)
1µF ±20% (X5R)
2.2µF +100/-50%
(Z5U)
VPERI
VCORE
CMOS
Sensor
2.8V
2.5V
100nF (Improved Noise Performance)
Microprocessor
AS1351_A7
VOUT1
1µF ±20% (X5R)
2.2µF +100/-50%
(Z5U)
VOUT2
VDD
EN1
EN2
GND
GND REF
3V
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AS1351
Data Sheet - Typical Ap plication
Figure 4. AS1351 Block Diagram
Thermal
Protection
Overcurrent
Protection
Softstart
Control
Thermal
Protection
Overcurrent
Protection
Softstart
Control
Reference
Voltage
VDD
VREF
VREF
EN1
EN2
GND
REF
VOUT1
VOUT2
AS1351
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AS1351
Data Sheet - Typical Ap plication
Package Drawings and Markings
The AS1351 is available in a 12-pin QFN 3x3mm package and a wafer bumped package.
Figure 5. 12-Pin QFN 3x3mm Package.
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AS1351
Data Sheet - Typical Ap plication
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AS1351
Data Sheet - Ordering Information
8 Ordering Information
The AS1351 is available with preset LDO output voltages or customer-specific versions (with a minimum order quantity
of 30,000). Each customer-specific device is factory trimmed to the desired output voltage (see Table 4).
Where:
u = Customer-specific VOUT1 value suffix.
x = Customer-specific VOUT2 value suffix.
Part Programming Pin Package
AS1351 LDO values not programmed 12-pin QFN 3x3
AS1351_A7 VOUT1 = 2.8V, VOUT2 = 2.5V 12-pin QFN 3x3
AS1351_ux Customer-specific LDO values 12-pin QFN 3x3
AS1351_uxF Customer-specific LDO values Bumped Wafer
Table 4. Output Voltages Suffix Guide
Part Suffix Output Voltage
AS1351_ux
F 3.3 V
E 3.2 V
D 3.1 V
C 3.0 V
B 2.9 V
A 2.8 V
9 2.7 V
8 2.6 V
7 2.5 V
6 2.4 V
5 2.3 V
4 2.2 V
3 2.1 V
2 2.0 V
1 1.9 V
0 1.8 V
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AS1351
Data Sheet
Copyrights
Copyright © 1997-2007, austriamicrosystems AG, Schloss Premstaetten, 8141 Unterpremstaetten, Austria-Europe.
Tr ademarks Registered ®. All rights reserved. The material herein may not be reproduced, adapted, merged, trans-
lated, stored, or used without the prior written consent of the copyright owner.
All products and companies mentioned are trademarks or registered trademarks of their respective companies.
Disclaimer
Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification provisions appearing
in its Term of Sale. austriamicrosystems AG makes no warranty, express, statutor y, implied, or by description regarding
the information set forth herein or rega rd i ng th e fre e do m of the described devices from patent infringement. austriami-
crosystems AG reserves the right to change specifications and prices at any time and withou t notice. Therefore, prior
to designing this product into a system, it is necessary to check with austriamicrosystems AG for current information.
This product is intended for use in normal commercial applications. Applicati ons requiring extended temperature
range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or life-
sustaining equipment are specifically not recommended without additional processing by austriamicrosystems AG for
each application. For shipments of less than 100 parts the manufacturing flow might show deviations from the standard
production flow, such as test flow or test location.
The information furnished here by austriamicrosystems AG is believed to be correct and accurate. However,
austriamicrosystems AG shall not be liable to recipient or any third party for any dama ges, including but not limited to
personal injury, property damage, loss of profits, loss of use, interrup tion of business or indirect, special, incidental or
consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the tech-
nical data herein. No obligation or liability to recipient or any third party shall arise or flow out of
austriamicrosystems AG rendering of technical or other services.
Cont act Information
Headquarters
austriamicrosystems AG
A-8141 Schloss Premstaetten, Austria
Tel: +43 (0) 3136 500 0
Fax: +43 (0) 3136 525 01
For Sales Offices, Distributors and Representatives, please visit:
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