AMSCO AS1323-27

AS1323
D a ta S he e t
1.6µA Quiescent Current, Single Cell, DC-DC Step-Up Converter
1 General Description
2 Key Features
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 12.
Table 1. Standard Products
Model
Fixed Output Voltage
Package
AS1323-27
2.7V
TSOT23-5
AS1323-30
3.0V
TSOT23-5
AS1323-33
3.3V
TSOT23-5
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.
!
1.6µA 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: 0.1µA
!
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
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
10µH
1
5
VBATT
VBATT
1
VSS
2
SHDNN
3
5
LX
4
VOUT
LX
10µF
AS1323
3
SHDNN
2
VSS
AS1323
4
VOUT
10µF
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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
VSS 2
SHDNN 3
5 LX
AS1323
4 VOUT
Pin Descriptions
Table 2. Pin Descriptions
Pin Number
1
2
Pin Name
VBATT
VSS
3
SHDNN
4
VOUT
5
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
Min
Max
Units
VDD, VBATT, SHDNN, LX to VSS
-0.3
+5
V
Comments
Maximum Current VOUT, LX
1
A
Thermal Resistance ΘJA
207.4
ºC/W
on PCB
Electro-Static Discharge
2
kV
HBM
Operating Temperature Range
-40
+85
ºC
Storage Temperature Range
-65
+150
ºC
+150
ºC
Junction Temperature
Package Body Temperature
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+260
ºC
Revision 1.02
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).
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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 = -40°C to +85°C, VBATT = 1.2V, VOUT = VOUT(NOM), SHDNN = VOUT, RLOAD = ∞, unless otherwise noted. Typical
values are at TA = 25°C.(unless otherwise specified). Limits are 100% production tested at TAMB = 25ºC. Limits over
the operating temperature range are guaranteed by design.
Table 4. Electrical Characteristics
Symbol
Parameter
VINMIN
Minimum Input Voltage
VIN
Operating Input Voltage
TAMB = 25ºC
VINSU
Minimum Start-Up
Input Voltage
TAMB = 25ºC,
RLOAD = 100Ω
VOUT
0.75
0.95
Unit
V
2
V
0.75
0.95
V
2.781
AS1323-30
2.91
3.0
3.09
AS1323-33
3.201
3.3
3.399
30
40
mV
N-Channel On-Resistance
0.5
1.0
Ω
P-Channel On-Resistance
0.75
1.5
Ω
N-Channel Switch
Current Limit
tON
VBATT = 1.5V;
ILOAD = 45mA
mA
Switch Maximum On-Time
6
µs
Synchronous Rectifier
Zero-Crossing Current
10
mA
6
µA
Operating Current
into VBATT
IQ-OUT
Quiescent Current to VOUT
IQ-BAT
Quiescent Current into
VBATT
Programmed at 400mA
V
400
IOP-OUT
1
Max
2.7
ILIMIT
ISDI-OUT
Typ
2.619
Load depended drop
of VOUT
RDS-ON
Min
AS1323-27
Output Voltage
RLOAD
Condition
VBATT = 1.5V, VOUT =
3.3V, TAMB = 25ºC
VBATT = 1.5V, TAMB = 25ºC
1.6
3
µA
0.3
1
µA
200
nA
Shutdown Current to VOUT
ISDI-BAT
Shutdown Current into
VBATT
VIL
SHDNN Voltage Threshold,
Low
VIH
SHDNN Voltage Threshold,
High
ISDI
SHDNN Input Bias Current TAMB = 25ºC, VSDI = VOUT
VBATT = 1.5V, TAMB = 25ºC
100
nA
150
mV
100
900
mV
300
nA
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 = 25°C; CIN = COUT = 10µF, L = 10µH, ILOAD = 10mA; VBATT = 1.5V; unless otherwise specified.
Figure 3. Efficiency vs. Output Current; VOUT= 3.3V
Figure 4. Efficiency vs. Output Current; VOUT= 3.0V
90
90
VIN = 1.8V
VIN = 1.8V
80
VIN = 1.2V
VIN = 1.5V
VIN = 0.95V
70
VIN = 1.5V
Efficiency (%) .
Efficiency (%) .
80
60
50
40
70
VIN = 1.2V
VIN = 0.95V
60
50
40
30
30
0.1
1
10
100
0.1
1
Output Current (mA)
Figure 5. Efficiency vs. Output Current; VOUT= 2.7V
3.32
VIN = 1.8V
3.315
80
Output Voltage (V) .
No Load
VIN = 1.5V
Efficiency (%) .
100
Figure 6. Output Voltage vs. Temperature
90
VIN = 1.2V
70
VIN = 0.95V
60
50
3.31
3.305
3.3
ILOAD = 10mA
3.295
3.29
ILOAD = 30mA
40
3.285
30
0.1
1
10
3.28
-50
100
-25
Output Current (mA)
25
50
75
100 125
Figure 8. Output Voltage vs. Input Voltage
3.4
3.4
3.35
3.38
Output Voltage (V) .
VIN = 1.5V
3.3
0
Temperature (°C)
Figure 7. Output Voltage vs. Output Current
Output Voltage (V) .
10
Output Current (mA)
VIN = 1.2V
3.25
3.2
3.15
3.1
3.05
3.36
3.34
3.32
3.3
3.28
3.26
3.24
3.22
3
3.2
0
10
20
30
40
50
60
70
0.9
Output Current (mA)
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1
1.1 1.2 1.3 1.4 1.5 1.6 1.7
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 9. Minimum Input Startup Voltage vs. Temp.
0.9
Input Current (nA) .
Input Voltage (V) .
Figure 10. Shutdown Current vs. Temperature
1000
1
0.8
0.7
VIN = 1.5V
100
VIN = 1.2V
10
1
0.6
0.5
-50
-25
0
25
50
75
100
125
0.1
-50
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-25
0
25
50
75
100
125
Temperature (°C)
Temperature (°C)
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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 1.6µA 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 7). The AS1323 also features an active-low shutdown circuit that supply current to 0.1µA.
Figure 11. Block Diagram
L1
4
1
VOUT
VBATT
0.95 to
1.6V
CIN
COUT
Comparator
Discharge
Comparator
Voltage
Control
Logic
Startup
System
Timing
3
SHDNN
AS1323
5
LX
Ref
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 6µs 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 12. Typical Application
10µH
1
5
VBATT
LX
10µF
AS1323
3
2
VSS
4
SHDNN
VOUT
10µF
Inductor Selection
The control scheme of the AS1323 allows for a wide range if inductor values. A 10µH inductor should be sufficient for
most applications (see Figure 12).
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:
V BATT ⋅ t ON
L > -------------------------------I LIMIT
(EQ 1)
tONMAX is 6µs (typ).
ILIMIT is 400mA (typ).
For larger inductor values, the peak inductor current (IPEAK) can be determined by:
The inductor’s incremental saturation current rating should be greater than the peak switching current. However, it is
V BATT ⋅ t ON
(EQ 2)
I PEAK = -------------------------------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 (η) as indicated in
the formula for determining IOUTMAX:
1
V BATT
I OUTMAX = --- ⋅ I PEAK ⋅ ⎛ -----------------⎞ ⋅ η
⎝ V OUT ⎠
2
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(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)
(EQ 4)
VRIPPLE(ESR) = IPEAK RESR(COUT)
(EQ 5)
2
2
1
L
V RIPPLE ( C ) ≈ --- ⋅ ⎛ --------------------------------------------------------------⎞ ⋅ ( I PEAK – I OUT )
2 ⎝ ( V OUT – V BATT ) ⋅ C OUT⎠
(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 10µF ceramic
capacitor and a 10µH 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
10 Package Drawings and Markings
The device is available in an TSOT23-5 package.
Figure 13. TSOT23-5 Package
Symbol
A
A1
A2
b
b1
c
Min
Typ
0.01
0.84
0.30
0.31
0.12
0.05
0.87
0.35
0.15
Max
1.00
0.10
0.90
0.45
0.39
0.20
c1
0.08
0.13
0.16
D
E
E1
e
e1
2.90BSC
2.80BSC
1.60BSC
0.95BSC
1.90BSC
Notes
3,4
3,4
3,4
Symbol
L
L1
L2
N
R
R1
θ
θ1
aaa
bbb
ccc
ddd
Min
0.30
Typ
0.40
0.60REF
0.25BSC
5
0.10
0.10
0º
Max
0.50
Notes
0.25
4º
8º
4º
10º
12º
Tolerances of Form and Position
0.15
0.25
0.10
0.20
Notes:
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 14. Tape&Reel Pin1 Orientation
User direction of feed
Top, Through View
TSOT23-5
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TSOT23-5
TSOT23-5
Revision 1.02
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
Marking
Description
Delivery Form
Package
AS1323-BTTT-27
ASJN
High-efficiency step-up DC-DC converter,
2.7V fixed output
Tape and Reel
TSOT23-5
AS1323-BTTT-30
ASMP
High-efficiency step-up DC-DC converter,
3.0V fixed output
Tape and Reel
TSOT23-5
AS1323-BTTT-33
ASMQ
High-efficiency step-up DC-DC converter,
3.3V fixed output
Tape and Reel
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
Copyrights
Copyright © 1997-2007, austriamicrosystems AG, Schloss Premstaetten, 8141 Unterpremstaetten, Austria-Europe.
Trademarks Registered ®. 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
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