AS1355
300mA, Triple LDO
www.austriamicrosystems.com/LDOs/AS1355 Revision 1.02 1 - 13
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 programma-
ble power supplies is optimized to deliver the best compromise
between quiescent 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 capacitors ensures low output impedance
at high frequencies.
Regulation performance is excellent even under low dropout condi-
tions, when the power transistor has to operate in linear mode.
The low-noise performance allows direct connection of noise sensi-
tive circuits without additional filtering networks.
The AS1355 is available in a 16-pin QFN 3x3 package.
Figure 1. AS1355 - Typical Application Di agram
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
Load Regulation: 3mV (0 to 300mA)
Supply Range: 2.3V to 5.5V
0.1V Dropout Voltage @ Iload = 200mA
Shutdown Current: 1µA
Supply Current Without Load: 160µA
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
Packages:
- 16-pin QFN 3x3
- 16-pin TQFN 3x3
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
CREF = 100nF
(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
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AS1355
Datasheet - Pinout
4 Pinout
Pin Assignments
Figure 2. Pin Assignments (Top Vie w)
Pin Descriptions
Table 1. Pin Descriptions
Pin Number Pin Name Description
1EN1
Active-High Enabel Input 1. Pull this pin to GND to disable the regulated output voltage VOUT1.
2 VDDA Analog Power Supply Voltage
3 VDD1 Unregulated Input Voltage 1
4 VDD2 Unregulated Input Voltage 2
5VOUT1
Regulated Output Voltage 1
6VOUT2
Regulated Output Voltage 2
7VOUT3
Regulated Output Voltage 3
8NC
Not Connected
9 VDD3 Unregulated Input Voltage 3
10 NC Not Connected
11, 12 GND Ground.
Note: All GND pins must be connected together externally.
13 REF Reference Voltage.
Note: Connect to a 100nF capacitor during normal operati on.
14 NC Not Connected
15 EN3 Active-High Enabel Input 3. Pull this pin to GND to disable the regulated output voltage VOUT3.
16 EN2 Active-High Enabel Input 2. Pull this pin to GND to disable the regulated output voltage VOUT2.
17 NC Exposed Pad. This pad is not connected internally, it can be connected to GND.
GND
VOUT2VOUT1
EN3 NC REF
13
6
12
NC
10
5
1415
EN1 1
VDDA 2
VDD2 4
AS1355
VDD1 3
VOUT3
7
NC
8
VDD3
9
GND
11
EN2
16
17
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AS1355
Datashee t - A b s o l u t e M a x i mu m R a t i n g s
5 Absolute Maximum Ratings
Stresses beyond those listed in Table 2 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 sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
Table 2. Absolute Maximum Ratings
Parameter Min Max Units Comments
Electrical Parameters
VDDx, ENx to GND -0.3 7 V
VOUTx to GND -0.3 5 V
All other pins to GND -0.3 VDD + 0.3 V
Electrostatic Discharge
Electrostatic Discharge HBM 2 kV Norm: MIL 883 E method 3015
Temperature Ranges and Storage Conditions
Thermal Resistance ΘJA 33 ºC/W on PCB
Junction Temperature +125 ºC
Storage Temperature Range -55 +125 ºC
Package Body Temperature +260 ºC
The reflow peak soldering temperature (body
temperature) specified is in accordance with IPC/
JEDEC J-STD-020“Moisture/Reflow Sensitivity
Classification for Non-Hermetic Solid State Surface
Mount Devices”.
Humidity non-condensing 5 85 %
Moisture Sensitive Level 3 Represents a max. floor life time of 168h
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AS1355
Datasheet - Electrical Characteristics
6 Electrical Characteristics
VDD = 4V, COUT = 1µF, typical values are for TAMB = 25°C (unless otherwise specified);
Note: All limits are guaranteed. The parameters with min and max values are guaranteed with production tests or SQC (Statistical Quality
Control) methods.
Table 3. Electrical Characteristics
Symbol Parameter Conditions Min Typ Max Unit
TAMB Operating Temperature Range -40 85 °C
VDD Supply Voltage Range 2.3 5.5 V
VOUT Output Voltage Range 1.25 3.6 V
RON On Resistance 0.5 Ω
PSRR 1
1. Guaranteed by design and verif ied by lab evaluation.
Power Supply
Rejection Ratio f = 1kHz, C REF = 100nF 70 dB
f = 100kHz, CREF = 100nF 60
IOFF Shut Down Current ENx = Low, TAMB = +25°C 1 µA
IVDD Supply Curre nt Without Load 160 240 µA
tset 1Output Voltage
Settling Time ILOAD Switched from 0 to 100mA 50 µs
tstart 1Start-up Time 2
2. Startup is performed if any EN pin goes high.
CREF = 100nF Pre-charged 300 µs
CREF = 0nF Uncharged 200 µs
CREF = 100nF Uncharged 15 ms
VOUT Output Voltage Tolerance ILOAD = 0mA, TAMB = 25°C -1 1 %
ILOAD = 0mA -2 2 %
VLINEREG Line Regulation, Static VOUT(NOM)+0.3V to 5.5V -1 1 %
VLOADREG 1Load Regulation, Static ILOAD = 0 to 50 mA 0.5 2.5 mV
ILOAD = 0 to 300 mA 3 10 mV
VIH Enable Input V oltage High 1.5 V
VIL Enable Input Voltage Low 0.4 V
ILOAD Output Current 0 300 mA
ILIMIT Output Current Limitation 450 mA
VNoise Output Noise Voltage 10Hz to 100kHz, CREF = 100nF 40 µVRMS
Thermal Protection 150 °C
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AS1355
Datasheet - Typical Operating Characteristics
7 Typical Operating Characteristics
VDD = 4V, VOUT = 3.3V, COUT = 1µF, TAMB = +25°C (unless otherwise specified);
Figure 3. Load Regulation; VOUT vs. IOUT Figure 4. Line Regulation; VOUT vs. VIN
3.24
3.26
3.28
3.3
3.32
3.34
3.36
0 50 100 150 200 250 300
Output Current (mA)
Out p ut V oltage (V)
1.76
1.77
1.78
1.79
1.8
1.81
1.82
1.83
1.84
22.533.544.555.5
Input Voltage (V )
Out p ut V oltage (V)
Figure 5. Output Voltage vs. Temp.; IOUT = 1mA Figure 6. Quiescent Current vs. Temperature
3.24
3.26
3.28
3.3
3.32
3.34
3.36
-45 -30 -15 0 15 30 45 60 75 90
T emperat ur e ( °C)
Out p ut V oltage (V)
80
100
120
140
160
180
200
220
240
-45 -30 -15 0 15 30 45 60 75 90
Temperature ( ° C)
Quiescent Current (µA)
Figure 7. Startup; no Load, no CREF Figure 8. Startup; RLOAD = 11Ω, no CREF
50µs/Div
VDD
1V/Div 2V/Div
VOUT
50µs/Div
VDD
1V/Div 2V/Div
VOUT
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AS1355
Datasheet - Typical Operating Characteristics
Figure 9. Startup; no Load, CREF = 100nF Figure 10. Startup; RLOAD = 11Ω, CREF = 100nF
2ms/Div
VDD
1V/Div 2V/Div
VOUT
2ms/Div
VDD
1V/Div 2V/Div
VOUT
Figure 11. Startup; no Load, CREF = 100nF (pre-charged) Figure 12. Startup; RLOAD = 11Ω, CREF = 100nF (pre-charged)
20µs/Div
EN
1V/Div 2V/Div
VOUT
20µs/Div
EN
1V/Div 2V/Div
VOUT
Figure 13. Load Transient Response; IOUT = 0 to
300mA Figure 14. Load T ransient Response; IOUT = 300 to
0mA
10µs/Div
IOUT
100mA/Div 20mV/Div
VOUT
500µs/Div
IOUT
100mA/Div 20mV/Div
VOUT
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AS1355
Datasheet - Detailed Description
8 Detailed Description
Figure 15. AS1355 - Bl ock Diagram
Thermal
Protection
Overcurrent
Protection
Softstart
Control
Thermal
Protection
Overcurrent
Protection
Softstart
Control
Reference
Voltage
Thermal
Protection
Overcurrent
Protection
Softstart
Control
VDD1
VDD3
VREF
VREF
VREF
EN1
EN2
EN3
GND
REF
VOUT1
VOUT2
VOUT3
AS1355
VDD2
VDDA
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AS1355
Datasheet - Package Drawings and Markings
10 Package Drawings and Markings
Figure 17. 16-pin QFN 3x3 Marking
Table 4. Packaging Code YYWWIZZ
YY WW XZZ
last two digits of the current year manufacturing week plant identifier free choice / traceability code
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AS1355
Datasheet - Ordering Information
11 Ordering Information
The devices are available as the standard products shown in Table 5.
Note: All products are RoHS compliant and austriamicrosystems green.
Buy our products or get free samples online at ICdirect: http://www.austriamicrosystems.com/ICdirect
Technical Support is found at http://www.austriamicrosystems.com/Technical-Support
For further information and requests, please contact us mailto:sales@austriamicrosystems.com
or find your local distributor at http://www.austriamicrosystems.com/distributo
*) These devices are available in factory-set output voltages from 1.25V to 3.6V in 100mV increments. Choose the desired VOUT suffi x from Table
6 and insert it instead of “xyz” in the part number .
On request also non-standard devices with output voltages between 1.25V and 3.6V in 50mV steps are available.
Table 5. Ordering Information
Ordering Code Marking Output Description Delivery Form Package
AS1355-BQFT-WGD ASSG VOUT1 = 3.3V 300mA, Triple LDO Tape and Reel 16-pin QFN 3x3VOUT2 = 1.8V
VOUT3 = 1.5V
AS1355-BQFT-WWW ASSV VOUT1 = 3.3V 300mA, Tri ple LDO Tape and Reel 16-pin QFN 3x3VOUT2 = 3.3V
VOUT3 = 3.3V
AS1355-BQFT-WWD2 ASTD VOUT1 = 3.3V 300mA, Triple LDO Tape and Reel 16-pin TQFN 3x3VOUT2 = 3.3V
VOUT3 = 1.5V
AS1355-BQFT-xyz* ____ VOUT1*300mA, Triple LDO Tape and Reel 16-pin QFN 3x3VOUT2*
VOUT3*
Table 6. Output Voltage Suffix Guide
Suffix Min Typ Max Suffix Min Typ Max Suffix Min Typ Max
A 1.25 J 2.1 S 3.0
B 1.3 K 2.2 T 3.1
C 1.4 L 2.3 V 3.2
D 1.5 M 2.4 W 3.3
E 1.6 N 2.5 X 3.4
F 1.7 O 2.6 Y 3.5
G 1.8 P 2.7 Z 3.6
H 1.9 Q 2.8 2 thin QFN
I 2.0 R 2.9
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AS1355
Datasheet
Copyrights
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All rights reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of
the copyright owner.
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austriamicrosystems AG makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding
the freedom of the described devices from patent infringement. austriamicrosystems AG reserves the right to change specifications and prices at
any time and without 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. Applications 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.
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