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AS1323
1 General Description
The AS1323 high-efficiency step-up DC-DC converter was designed specifically for single-cell, battery-powered devices where lowest quiescent current and high efficiency are essential. The compact device is available in three fixed-voltage variations and is perfect for a wide variety of applications where extremely-low quiescent currents and very-small form factors are critical. The devices are available as the standard products shown in Table 1. See also Ordering Information on page 13. Table 1. Standard Products Model AS1323-27 AS1323-30 AS1323-33 Fixed Output Voltage 2.7V 3.0V 3.3V Package TSOT23-5 TSOT23-5 TSOT23-5
! ! ! !
D a ta S he e t
1 . 6 A Q u i e s c e n t C u r r e n t , S i n g l e C e l l , D C - D C St e p - u p C o n v e r t e r
2 Key Features
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1.6A Quiescent Current Input Voltage Range: 0.75 to 2V Up to 100mA Output Current Fixed Output Voltages: 2.7, 3.0 and 3.3V Shutdown Current: 0.1A Output Voltage Accuracy: 3% Efficiency: Up to 85% No External Diode or FETs Needed Output Disconnect in Shutdown Guaranteed 0.95V Start-Up Voltage TSOT23-5 Package
Integrated boot circuitry ensures start-up even with veryhigh load currents. The true output disconnect feature completely disconnects the output from the battery during shutdown. The device is available in a TSOT23-5 pin package.
3 Applications
The devices are ideal for single-cell portable devices including mobile phones, MP3 players, PDAs, remote controls, personal medical devices, wireless transmitters and receivers, and any other battery-operated, portable device.
Figure 1. Typical Operating Circuit
10H
1 VBATT 10F
5 LX
VBATT
1
5
LX
AS1323
3 SHDNN
2 VSS VSS 2
AS1323
4 VOUT 10F SHDNN 3 4 VOUT
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AS1323
Data Sheet - P i n o u t
4 Pinout
Pin Assignments
Figure 2. Pin Assignments (Top View)
VBATT 1
5 LX
VSS 2
AS1323
SHDNN 3
4 VOUT
Pin Descriptions
Table 2. Pin Descriptions Pin Number 1 2 3 4 5 Pin Name VBATT VSS SHDNN VOUT LX Description Battery Supply Input and Coil Connection Negative Supply and Ground Shutdown Input. 0 = Shutdown mode. 1 = Normal operating mode. Output. This pin also supplies bootstrap power to the device. Inductor Connection. This pin is connected to the internal N-channel MOSFET switch drain and P-channel synchronous rectifier drain.
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AS1323
Data Sheet - A b s o l u t e M a x i m u m R a t i n g s
5 Absolute Maximum Ratings
Stresses beyond those listed in Table 3 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 Electrical Characteristics on page 4 is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Table 3. Absolute Maximum Ratings Parameter VBATT, SHDNN, LX to VSS Maximum Current VOUT, LX Thermal Resistance JA Electro-Static Discharge Operating Temperature Range Storage Temperature Range Junction Temperature -40 -65 Min -0.3 Max +5 1 207.4 2 +85 +150 +150 Units V A C/W kV C C 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". The lead finish for Pb-free leaded packages is matte tin (100% Sn). on PCB HBM Comments
Package Body Temperature
+260
C
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AS1323
Data Sheet - E l e c t r i c a l C h a r a c t e r i s t i c s
6 Electrical Characteristics
DC Electrical Characteristics
TAMB = -40C to +85C, VBATT = 1.2V, VOUT = VOUT(NOM), SHDNN = VOUT, RLOAD = , unless otherwise noted. Typical values are at TA = 25C.(unless otherwise specified). Limits are 100% production tested at TAMB = 25C. Limits over the operating temperature range are guaranteed by design. Table 4. Electrical Characteristics Symbol VINMIN VIN VINSU Parameter Minimum Input Voltage Operating Input Voltage Minimum Start-Up Input Voltage TAMB = 25C TAMB = 25C, RLOAD = 100 AS1323-27 VOUT Output Voltage AS1323-30 AS1323-33 RLOAD RDS-ON ILIMIT tON Load depended drop of VOUT N-Channel On-Resistance P-Channel On-Resistance N-Channel Switch Current Limit Switch Maximum On-Time Synchronous Rectifier Zero-Crossing Current IOP-OUT IQ-OUT IQ-BAT ISDI-OUT ISDI-BAT VIL VIH ISDI
1
Condition
Min
Typ 0.75
Max
Unit V
0.95 0.75 2.619 2.91 3.201 2.7 3.0 3.3 30 0.5 0.75
2 0.95 2.781 3.09 3.399 40 1.0 1.5
V V
V
VBATT = 1.5V; ILOAD = 45mA
mV mA s mA A
Programmed at 400mA
400 6 10
Operating Current into VBATT Quiescent Current to VOUT Quiescent Current into VBATT Shutdown Current to VOUT Shutdown Current into VBATT SHDNN Voltage Threshold, Low SHDNN Voltage Threshold, High
VBATT = 1.5V, VOUT = 3.3V, TAMB = 25C
6 1.6 3 1 200
A A nA nA mV
VBATT = 1.5V, TAMB = 25C
0.3
VBATT = 1.5V, TAMB = 25C 150
100
900 100 300
mV nA
SHDNN Input Bias Current TAMB = 25C, VSDI = VOUT
1. VOUT is completely disconnected (0V) during shutdown.
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AS1323
Data Sheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s
7 Typical Operating Characteristics
VOUT= 3.3V; TA = 25C; CIN = COUT = 10F, L = 10H, ILOAD = 10mA; VBATT = 1.5V; unless otherwise specified. Figure 3. Efficiency vs. Output Current; VOUT = 3.3V
90
VIN = 1.8V
Figure 4. Efficiency vs. Output Current; VOUT = 3.0V
90
VIN = 1.8V
80
VIN = 1.2V
80
VIN = 1.5V
Efficiency (%) .
Efficiency (%) .
VIN = 1.5V
70 60 50 40 30 0.1 1
VIN = 0.95V
70 60 50 40 30
VIN = 1.2V VIN = 0.95V
10
100
0.1
1
10
100
Output Current (mA) Figure 5. Efficiency vs. Output Current; VOUT = 2.7V
90
VIN = 1.8V
Output Current (m A)
Figure 6. Efficiency vs. Input Voltage
90 80
80
VIN = 1.5V
Efficiency (%) .
70 60 50 40 30 0.1
VIN = 1.2V VIN = 0.95V
Efficiency (%) .
70 60 50 40 30 0.75
Il oad = 80A Il oad = 800A Il oad = 11mA
1
10
100
1
1.25
1.5
1.75
2
Output Current (m A)
Figure 7. Output Voltage vs. Temperature
3.32 3.315
No Load
Input Voltage (V)
Figure 8. Output Voltage vs. Output Current
3.4 3.35
VIN = 1.5V VIN = 1.2V
Output Voltage (V) .
3.31 3.305 3.3 3.295 3.29
ILOAD = 30mA ILOAD = 10mA
Output Voltage (V) .
75 100 125
3.3 3.25 3.2 3.15 3.1 3.05 3
3.285 3.28 -50 -25 0 25 50
0
10
20
30
40
50
60
70
Tem perature (C)
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Output Current (m A)
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AS1323
Data Sheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s
Figure 9. Output Voltage vs. Input Voltage
3.4 3.38
Figure 10. Shutdown Current vs. Temperature
1000
Output Voltage (V) .
Input Current (nA) .
3.36 3.34 3.32 3.3 3.28 3.26 3.24 3.22 3.2 0.9 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7
100
VIN = 1.5V
10
VIN = 1.2V
1
0.1 -50 -25 0 25 50 75 100 125
Input Voltage (V)
Tem perature (C)
Figure 11. Minimum Input Startup Votage vs. Temperature
1
Figure 12. Output Voltage vs. Input Voltage; VOUT = 2.7V
2.78 2.76
Output Voltage (V) .
Input Voltage (V) .
0.9
2.74 2.72 2.7 2.68 2.66 2.64
IOUT = 0mA IOUT = 10mA IOUT = 30mA
0.8
0.7
0.6
0.5 -50 -25 0 25 50 75 100 125
2.62 0.75
1
1.25
1.5
1.75
2
Tem perature (C)
Figure 13. Output Voltage vs. Input Voltage; VOUT = 3.0V
3.1 3.08
Input Voltage (V)
Figure 14. Output Voltage vs. Input Voltage; VOUT = 3.3V
3.4 3.38
Output Voltage (V) .
3.04 3.02 3 2.98 2.96 2.94 2.92 2.9 0.75 1
IOUT = 0mA IOUT = 10mA
Output Voltage (V) .
3.06
3.36 3.34 3.32 3.3 3.28 3.26 3.24 3.22
IOUT = 30mA IOUT = 0mA IOUT = 10mA
IOUT = 30mA
1.25
1.5
1.75
2
3.2 0.75
1
1.25
1.5
1.75
2
Input Voltage (V)
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AS1323
Data Sheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s
Figure 15. Output Current vs. Input Voltage
110 100
Figure 16.
Switching Waveform; VOUT = 2.7V
Output Current (mA)
VOUT = 3.0V
80 70
VOUT = 3.3V
VOUT
90
60 50 40 30 20 0.75
VOUT = 2.7V
1
1.25
1.5
1.75
2
200s/Div
Input Voltage (V)
Figure 17. Switching Waveform; VOUT = 3.0V
Figure 18. Switching Waveform; VOUT = 3.3V
50mV/Div
2V/Div
20mA/DIV
200s/Div
200s/Div
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20mA/DIV
ILX
ILX
2V/Div
VLX
VLX
50mV/Div
VOUT
VOUT
20mA/DIV
ILX
2V/Div
VLX
50mV/Div
.
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AS1323
Data Sheet - D e t a i l e d D e s c r i p t i o n
8 Detailed Description
The AS1323 is a compact, high-efficiency, step-up DC-DC converter guaranteed to start up with voltages as low as 0.95V, and operate with an input voltage down to 0.75V. Consuming only 1.6A of quiescent current, the device includes an integrated synchronous rectifier that eliminates the need for an external diode and improves overall efficiency by minimizing losses (see Synchronous Rectification on page 8). The AS1323 also features an active-low shutdown circuit that supply current to 0.1A. Figure 19. Block Diagram
L1 1 4 VOUT Comparator Discharge Comparator Voltage COUT
0.95 to 1.6V
VBATT CIN
3 SHDNN
AS1323
Ref
Control Logic Startup System Timing
5 LX
Comparator Charge
2 VSS
PFM Control
A forced discontinuous, current-limited, pulse-frequency modulation (PFM) control scheme provides ultra-low quiescent current and high efficiency over a wide output current-range. Rather than using an integrated oscillator, the inductor current is limited by the 400mA N-channel current limit or by the 6s switch maximum on-time. After each device-on cycle, the inductor current must ramp to zero before another cycle can start. When the error comparator senses that the output has fallen below the regulation threshold, another cycle can begin.
Synchronous Rectification
The integrated synchronous rectifier eliminates the need for an external Schottky diode, reducing cost and PCB space. During normal operation, while the inductor discharges, the P-channel MOSFET turns on and shunts the MOSFET body diode. Consequently the rectifier voltage drop is significantly reduced improving efficiency without the need for external components.
Low-Voltage Startup Circuit
The AS1323 contains a unique low-voltage startup circuit which ensures start-up even with very high load currents. The minimum start-up voltage is independent of the load current. This device is powered from pin VBATT, guaranteeing startup at input voltages as low as 0.95V.
Shutdown
The AS1323 enter shutdown when the SHDNN pin is driven low. During shutdown, the output is completely disconnected from the battery. Shutdown can be pulled as high as 3.6V, regardless of the voltage at pins VBATT or VOUT. For normal operation, connect SHDN to the input.
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AS1323
Data Sheet - A p p l i c a t i o n I n f o r m a t i o n
9 Application Information
Figure 20. Typical Application
10H
1 VBATT 10F
5 LX
AS1323
3 SHDNN
2 VSS
4 VOUT 10F
Inductor Selection
The control scheme of the AS1323 allows for a wide range if inductor values. A 10H inductor should be sufficient for most applications (see Figure 20). Smaller inductance values typically offer smaller physical size for a given series resistance, allowing the smallest overall circuit dimensions. Applications using larger inductance values may startup at lower battery voltages, provide higher efficiency and exhibit less ripple, but they may reduce the maximum output current. This occurs when the inductance is sufficiently large to prevent the maximum current limit (ILIMIT) from being reached before the maximum on-time (tON) expires (see Electrical Characteristics on page 4). For maximum output current, the inductor value should be chosen such that the controller reaches the current-limit before the maximum on-time is triggered:
VBATT tON L > ------------------------------ILIMIT
tONMAX is 6s (typ). ILIMIT is 400mA (typ). For larger inductor values, the peak inductor current (IPEAK) can be determined by:
(EQ 1)
The inductor's incremental saturation current rating should be greater than the peak switching current. However, it is
VBATT tON (EQ 2) IPEAK = ------------------------------L generally advisable to bias the inductor into saturation by as much as 20%, although this will slightly reduce efficiency.
Maximum Output Current
The maximum output current (IOUTMAX) is a function of IPEAK, VIN, VOUT, and the overall efficiency () as indicated in the formula for determining IOUTMAX: 1 VBATT IOUTMAX = -- IPEAK ---------------- VOUT 2 (EQ 3)
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AS1323
Data Sheet - A p p l i c a t i o n I n f o r m a t i o n
Capacitor Selection
Choose input and output capacitors to supply the input and output peak currents with acceptable voltage ripple. The input filter capacitor (CIN) reduces peak currents drawn from the battery and improves efficiency. Low equivalent series resistance (ESR) capacitors are recommended. Note: Ceramic capacitors have the lowest ESR, but low ESR tantalum or polymer capacitors offer a good balance between cost and performance. Output voltage ripple has two components: variations in the charge stored in the output capacitor with each COIL pulse, and the voltage drop across the capacitor's ESR caused by the current into and out of the capacitor: VRIPPLE = VRIPPLE(C) + VRIPPLE(ESR) VRIPPLE(ESR) = IPEAK RESR(COUT)
2 2 1 L VRIPPLE ( C ) -- -------------------------------------------------------------- ( IPEAK - IOUT ) 2 ( VOUT - VBATT ) COUT
(EQ 4) (EQ 5) (EQ 6)
Where: IPEAK is the peak inductor current. For ceramic capacitors, the output voltage ripple is typically dominated by VRIPPLE(C). For example, a 10F ceramic capacitor and a 10H inductor typically provide 75mV of output ripple when stepping up from 1.2V to 3.3V at 50mA. Low input-to-output voltage differences require higher output capacitor values. Capacitance and ESR variation of temperature should be considered for best performance in applications with wide operating temperature ranges.
PC Board Layout Considerations
The AS1323 has been specially designed to be tolerant to PC board parasitic inductances and resistances. However, to achieve maximum efficiency a careful PC board layout and component selection is vital. Note: For the optimal performance the IC's VSS and the ground leads of the input and output capacitors must be kept less than 5mm apart using a ground plane. In addition, keep all connections to COIL as short as possible. The system robustness guarantees a reliable operation even if those recommendations are not fully applied.
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AS1323
Data Sheet - P a c k a g e D r a w i n g s a n d M a r k i n g s
10 Package Drawings and Markings
The device is available in an TSOT23-5 package. Figure 21. TSOT23-5 Package
Symbol A A1 A2 b b1 c c1 D E E1 e e1 Notes:
Min 0.01 0.84 0.30 0.31 0.12 0.08
Typ 0.05 0.87 0.35 0.15 0.13 2.90BSC 2.80BSC 1.60BSC 0.95BSC 1.90BSC
Max 1.00 0.10 0.90 0.45 0.39 0.20 0.16
Notes
Symbol L L1 L2 N R R1
Min 0.30
Typ 0.40 0.60REF 0.25BSC 5
Max 0.50
Notes
0.10 0.10 0 4
0.25 8
3,4 3,4 3,4
1
aaa bbb ccc ddd
4 10 12 Tolerances of Form and Position 0.15 0.25 0.10 0.20
1. Dimensioning and tolerancing conform to ASME Y14.5M - 1994. 2. Dimensions are in millimeters. 3. Dimension D does not include mold flash, protrusions, or gate burrs. Mold flash, protrusions, and gate burrs shall not exceed 0.15mm per end. Dimension E1 does not include interlead flash or protrusion. Interlead flash or protrusion shall not exceed 0.15mm per side. Dimensions D and E1 are determined at datum H. 4. The package top can be smaller than the package bottom. Dimensions D and E1 are determined at the outermost extremes of the plastic body exclusive of mold flash, tie bar burrs, gate burrs, and interlead flash, but include any mistmatches between the top of the package body and the bottom. D and E1 are determined at datum H.
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AS1323
Data Sheet - P a c k a g e D r a w i n g s a n d M a r k i n g s
Tape and Reel Pin1 Orientation
Figure 22. Tape&Reel Pin1 Orientation
Top, Through View
User direction of feed
TSOT23-5
TSOT23-5
TSOT23-5
TSOT23-5
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AS1323
Data Sheet - O r d e r i n g I n f o r m a t i o n
11 Ordering Information
The device is available as the standard products shown in Table 5. Table 5. Ordering Information Model AS1323-BTTT-27 AS1323-BTTT-30 AS1323-BTTT-33 Marking ASJN ASMP ASMQ Output 2.7V 3.0V 3.3V Description 1.6A Quiescent Current, Single Cell, DC-DC Step-up Converter 1.6A Quiescent Current, Single Cell, DC-DC Step-up Converter 1.6A Quiescent Current, Single Cell, DC-DC Step-up Converter Delivery Form Tape and Reel Tape and Reel Tape and Reel Package TSOT23-5 TSOT23-5 TSOT23-5
All devices are RoHS compliant and free of halogene substances.
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AS1323
Data Sheet
Copyrights
Copyright (c) 1997-2009, austriamicrosystems AG, Schloss Premstaetten, 8141 Unterpremstaetten, Austria-Europe. Trademarks Registered (R). 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. 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, 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 lifesustaining 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 damages, including but not limited to personal injury, property damage, loss of profits, loss of use, interruption 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 technical 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.
Contact 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: http://www.austriamicrosystems.com/contact-us
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