a us t ria
m i c r o
s y s t e m s
AS1351
Programmable Dual LDO
D a ta S he e t
1 General Description
The AS1351 is a high-performance dual CMOS low-drop-
out voltage regulator in a single 3x3 package. The efficient
set of programmable power supplies is optimized to deliver
the best compromise between quiescent current and regu-
lator 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 as well as full-
production in the field. Factory trimmed versions are also
available.
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 capacitors
ensures low output impedance at high frequencies.
Regulation performance is excellent even under low drop-
out 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 networks.
The AS1351 is available in a 12-pin QFN 3x3 package or in
a wafer bumping package.
2 Key Features
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2 Independent Voltage Regulators with Shutdown
Output Current: 200mA each LDO
One Time Programmable Output Voltage
(User- or Factory-Trimmed)
Programmable Output Voltage Range: 1.8 to 3.3V in
0.1V Steps
Accuracy: ±1%
PSRR: 70dB at 1kHz, 40dB at 100kHz
Line Regulation: ±2mV
Load Regulation: ±0.6mV
Supply Range: 3 to 5.5V
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
Wafer Bumping
QFN12 3x3, Pitch 0.8mm Package
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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
.
Figure 1. Pinout Assignments (Top View)
N/C
12
N/C
11
REF
10
EN2
1
9
V
DD
EN1
2
AS1351
8
N/C
GND
3
7
V
DD
4
TRIM
5
6
13
GND (Exposed Pad)
V
OUT1
V
OUT2
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Revision 1.09
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AS1351
Data Sheet
austriam
i c r o
systems
5 Absolute Maximum Ratings
Stresses beyond those listed in Table 1 may cause permanent damage to the device. These are stress ratings only,
and functional operation of the device at these or any other conditions beyond those indicated in the operational sec-
tions of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may
affect device reliability.
Table 1. Absolute Maximum Ratings
Parameter
V
DD
to GND
Any other Pin to GND
Continuous Power Dissipation
QFN12 3x3mm
Min
-0.3
-0.3
590
Max
7
V
DD
+ 0.3
1500
Units
V
V
mW
Min value measured at T
AMB
= 85°C;
max value measured at T
AMB
= 25°C
The reflow peak soldering temperature
(body temperature) specified is in
accordance with
IPC/JEDEC J-STD-020C “Moisture/
Reflow Sensitivity Classification for
non-hermetic
Solid State Surface Mount Devices”.
Comments
Package-Body Peak
Temperature
260
°C
Operating Ambient
Temperature
Storage Temperature
Electrostatic Discharge
Protection (ESD) Level
-40
-65
1
85
150
°C
°C
kV
HBM – Norm: MIL 883 E method 3015
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Revision 1.09
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AS1351
Data Sheet
austriam
i c r o
systems
6 Electrical Characteristics
V
DD
= 4V; T
AMB
= -40 to +85°C (Typ values are for T
AMB
= 25°C); C
LOAD
= 1µF (Ceramic); unless otherwise specified.
Table 2. Electrical Characteristics
Symbol
V
DD
V
OUT
R
ON
PSRR
1
I
OFF
I
VDD
t
set
1
Parameter
Supply Voltage Range
Output Voltage Range
On Resistance
Power Supply Rejection
Ratio
Shut Down Current
Supply Current
Output Voltage Settling
Time
f = 1kHz, C
REF
= 100nF
f = 100kHz, C
REF
= 100nF
ENx = Low
Without Load
I
LOAD
Switched from 0 to 100mA
C
REF
= 100nF Pre-charged
t
start
1
Start-Up Time
2
C
REF
= 0nF Uncharged
C
REF
= 100nF Uncharged
V
OUT
Output Voltage Tolerance
I
LOAD
= 0mA
I
LOAD
= 0 to 200mA, T
AMB
= 25°C
V
DD
= 5.5V
V
LINEREG
Line Regulation, Static
V
DD
= 3 to 4.5V
I
LOAD
= 0 to 50 mA
V
LOADREG
V
IH
V
IL
I
LOAD
I
LIMIT
V
Noise
Load Regulation, Static
Enable Input Voltage High
Enable Input Voltage Low
Output Current
Output Current Limitation
Output Noise Voltage
Thermal Protection
Notes:
1. Guaranteed by design and verified by lab evaluation.
2. Startup is performed if any EN pin goes high.
10 to 100kHz, C
REF
= 100nF
0
400
40
145
I
LOAD
= 0 to 200 mA
(referenced to 100mA)
0.6 x V
DD
0.8
200
-1
-2
-1
-2
0.3
0.6
300
15
1
2
1
2
2.5
5
125
70
40
1
200
50
300
Conditions
Min
3
1.8
Typ
Max
5.5
3.3
1
Unit
V
V
Ω
dB
µA
µA
µs
µs
µs
ms
%
%
1
%
mV
1
mV
1
mV
1
V
V
mA
mA
µV
RMS
°C
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Revision 1.09
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AS1351
Data Sheet
austriam
i c r o
systems
One-Time Programming Procedure Output Voltages
7 Typical Application
Figure 3. Typical AS1351_ux Application
V
DD
V
OUT1
2.8V
V
PERI
1µF ±20% (X5R)
2.2µF +100/-50%
(Z5U)
3V
CMOS
Sensor
EN1
V
OUT2
2.5V
V
CORE
1µF ±20% (X5R)
2.2µF +100/-50%
(Z5U)
Microprocessor
EN2
TRIM
GND
AS1351_A7
REF
100nF (Improved Noise Performance)
7.1 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, the AS1351 is available in pre-programmed versions with fixed output voltages (see Ordering Information
on page 9.)
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