Analogic AAT1265IJS-3.3-T1 Low voltage 2mhz step-up dc/dc converter in sc70jw package Datasheet

AAT1265
Low Voltage 2MHz Step-Up DC/DC
Converter in SC70JW Package
General Description
Features
The AAT1265 is a member of Analogic Tech's Total
Power Management IC™ (TPMIC™) product family
and is designed for single-cell or dual-cell alkaline,
NiMH, or NiCd battery-powered applications. It is a
high efficiency, synchronous, fixed frequency, stepup converter with true output disconnect during
shutdown (<1.0µA), start-up inrush current limit, and
short-circuit protection.
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The high 2MHz switching frequency and completely
integrated control circuitry minimize the total solution
footprint area while maintaining excellent regulation,
ripple, and transient response throughout the full
load range.
Light load switching frequency modulation and low
quiescent current maintain high efficiency performance for light load and sleep mode conditions.
With a 1A peak switch current limit, the AAT1265 is
capable of delivering 100mA to a 3.3V load with a
single AA cell or up to 250mA from a dual AA cell.
The device has a 1.0V start-up voltage with operation down to 0.8V.
The AAT1265 is available in a Pb-free, space-saving 2.0x2.1mm 8-pin SC70JW package and is
rated over the -40°C to +85°C temperature range.
SwitchReg™
100mA Output from a Single AA Cell Input
250mA Output from a Dual AA Cell Input
VIN Operation Range: 0.8V to VOUT
Up to 93% Efficiency
Low Start-Up Voltage: 1.0V Typical
Internal Synchronous Rectifier
Current Mode Control with Internal Feedback
and Compensation
2MHz Fixed Switching Frequency
1A Current Limit
Maintains High Efficiency Over the Output
Current Range for Improved Battery Life
Low 40µA No Load Bias Current
True Load Disconnect
Short-Circuit and Over-Current Protection
Inrush Current Limit and Soft Start
Low Shutdown Current: <1.0µA
-40°C to +85°C Temperature Range
2.0x2.1mm SC70JW-8 Package
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Applications
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Bluetooth™ Headsets
Digital Cameras
Medical Instruments
Mobile Handsets
MP3 and Portable Music Players
Typical Application
VIN
Dual-Cell to 3.3V Efficiency
vs. Output Current
VOUT
100
AAT1265
LX
VCC
VIN
OUT
VIN = 3.0V
90
4.7µF
4.7µF
EN
GND
Efficiency (%)
2.2µH
80
VIN = 2.4V
VIN = 2.0V
70
60
50
0.1
1.0
10.0
100.0
1000.0
Output Current (mA)
1265.2006.05.1.1
1
AAT1265
Low Voltage 2MHz Step-Up DC/DC
Converter in SC70JW Package
Pin Descriptions
Pin #
Symbol
1
2
VCC
EN
3
4
VIN
LX
5
OUT
6, 7, 8
GND
Function
Bias supply voltage after start-up and feedback to the output voltage error amplifier.
Enable pin. Logic high enables the IC. Logic low disables the IC and disconnects the
load from the input. Shutdown current is <1µA.
Battery input voltage. Supplies the IC at start-up.
Inductor connection. Ties to the drains of the P-channel synchronous rectifier and the
N-channel MOSFET switch.
Boost converter output voltage; connects to the P-channel synchronous MOSFET
source. Bypass with ceramic capacitor to GND.
Signal and power ground. Connect output capacitor return.
Pin Configuration
SC70JW-8
(Top View)
VCC
EN
VIN
LX
2
1
8
2
7
3
6
4
5
GND
GND
GND
OUT
1265.2006.05.1.1
AAT1265
Low Voltage 2MHz Step-Up DC/DC
Converter in SC70JW Package
Absolute Maximum Ratings
Symbol
VN
TJ
TLEAD
Description
VIN, OUT, VCC, EN, LX to GND
Operating Junction Temperature Range
Maximum Soldering Temperature (at leads, 10 sec)
Value
Units
-0.3 to 6.0
-40 to 150
300
V
°C
°C
Value
Units
160
625
°C/W
mW
Thermal Characteristics1
Symbol
θJA
PD
Description
Maximum Thermal Resistance
Maximum Power Dissipation
1. Mounted on an FR4 board.
1265.2006.05.1.1
3
AAT1265
Low Voltage 2MHz Step-Up DC/DC
Converter in SC70JW Package
Electrical Characteristics1
VIN = 1.2V, VOUT = 3.3V, TA = -40°C to +85°C, unless otherwise noted. Typical values are TA = 25°C.
Symbol
VIN
VOUT
IQ
ISHDN
RDS(ON)H
RDS(ON)L
ILIMIT
IPFM
η
ΔVOUT/VOUT
ΔVOUT(VOUT*ΔVIN)
FOSC
DTYMAX
VTH(L-IN)
VTH(H-IN)
Description
Conditions
Minimum Start-Up Voltage
Operating Input Voltage Range
ILOAD = 1mA
Output Voltage Accuracy
Quiescent Supply Current
(PFM Operation)2
Shutdown Current
PMOS On-Resistance
NMOS On-Resistance
NMOS Current Limit
PFM Light Load Current Threshold
Efficiency
Load Regulation
Line Regulation
Switching Frequency
Maximum Duty Cycle
Logic Input Low Threshold for EN
Logic Input High Threshold for EN
Min
Typ
1.0
0.8
VIN = 0.8V to 2.5V,
PWM Mode
3.2
No Load
EN = 0V, VIN = 5.5V
TA = 25°C
TA = 25°C
IOUT = 50mA, L = 2.2µH
ILOAD = 0 to 100mA
VIN = 0.8V to 2.5V
TA = 25°C
Max
1.8
VOUT
V
3.3
3.4
V
40
70
µA
1.0
µA
mΩ
mΩ
A
mA
%
%
%/V
MHz
%
V
V
750
400
1.0
20
82
1.5
0.2
2.0
90
2.2
0.4
1.0
Units
1. The AAT1265 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range and is assured
by design, characterization, and correlation with statistical process controls.
2. IQ = IQ_VOUT = IQ_VCC.
4
1265.2006.05.1.1
AAT1265
Low Voltage 2MHz Step-Up DC/DC
Converter in SC70JW Package
Typical Characteristics
Single-Cell to 3.3V Efficiency
Dual-Cell to 3.3V Efficiency
100
100
VIN = 3.0V
90
VIN = 1.5V
Efficiency (%)
Efficiency (%)
90
80
70
VIN = 1.2V
80
VIN = 2.4V
70
60
60
50
50
0.1
1
10
100
0.1
1000
1
Output Current (mA)
10
2.0
1.5
1.5
1.0
1.0
VOUT Error (%)
VOUT Error (%)
(VO = 3.3V)
2.0
0.5
0.0
VIN = 1.5V
-1.0
-1.5
0.1
0.5
VIN = 3.0V
0.0
VIN = 2.4V
-0.5
-1.0
-1.5
VIN = 1.2V
-2.0
1000
Dual-Cell Load Regulation
(VO = 3.3V)
-0.5
100
Output Current (mA)
Single-Cell Load Regulation
VIN = 2.0V
-2.0
1
10
0.1
100
1
10
100
1000
Output Current (mA)
Output Current (mA)
Minimum Start-Up Voltage vs. Load Current
PFM Mode Output Current Threshold
vs. Input Voltage
120
2.4
Output Current (mA)
2.2
Constant Current Load
2.0
Voltage (V)
VIN = 2.0V
1.8
1.6
1.4
Resistive Load
1.2
1.0
100
Increasing Load
80
60
40
Decreasing Load
20
0
0.8
0
2
40
60
80
100
Current (mA)
1265.2006.05.1.1
120
140
160
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
Input Voltage (V)
5
AAT1265
Low Voltage 2MHz Step-Up DC/DC
Converter in SC70JW Package
Typical Characteristics
Switching Frequency vs. Temperature
Input Current (µA)
200
160
120
80
40
0
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
Switching Frequency Change (%)
No Load Input Current vs. Input Voltage
0.5
0.0
-0.5
-1.0
-1.5
-2.0
-2.5
-40
-15
10
35
60
85
Temperature (°°C)
Input Voltage (V)
Load Transient Response
Maximum Load Current Capacity for a 4%
Drop in Output Voltage vs. Input Voltage
(VIN = 1.2V; L = 2.2µH; CO = 4.7µF)
(VOUT = 3.3V)
3.40
Output Current (A)
500
400
300
200
100
0
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.35
3.30
3.25
3.20
0.15
0.10
100mA
0.05
Output Voltage (V)
Load Current (mA)
600
50mA
0.00
3.0
Time (50µs/div)
Input Voltage (V)
Output Voltage vs. Temperature
Line Transient Response
(VIN = 1.5V; IO = 10mA)
(IO = 50mA; L = 2.2µH; CO = 4.7µF)
2.50
2.4V
Output Voltage (V)
0.20
0.00
-0.20
-0.40
-0.60
-0.80
-40
-20
0
20
40
Temperature (°°C)
6
60
80
2.25
2.00
1.9V
3.34
1.75
1.50
3.32
3.30
Input Voltage (V)
Output Voltage Error (%)
0.40
3.28
3.26
Time (50µs/div)
1265.2006.05.1.1
AAT1265
Low Voltage 2MHz Step-Up DC/DC
Converter in SC70JW Package
Soft-Start Inrush Current
(VIN = 2.4V; IO = 100mA; VO = 3.3V)
1.75
4
3
Output Voltage
1.5
1
Enable
0
0.75
0.5
-1
-2
1
Input Current
0.25
-3
0
-4
-0.25
3
Output Voltage
1.5
1.25
2
1
1
Enable
0
-1
-3
0.75
0.5
-2
0.25
Input Current
-4
Time (500µs/div)
0
-0.25
Time (500µs/div)
Full Load Output Ripple
Light Load Output Ripple
(VIN = 1.2V; 100mA Load)
(VIN = 1.2V; 10mA Load)
VOUT
(AC Coupled)
(20mV/div)
VOUT
(AC Coupled)
(20mV/div)
IL
(100mA/div)
IL
(200mA/div)
VLX
(2V/div)
VLX
(2V/div)
Time (250ns/div)
1265.2006.05.1.1
1.75
4
Input Current (A)
1.25
2
Enable and Output Voltage (V)
Soft-Start Inrush Current
(VIN = 1.2V; IO = 40mA; VO = 3.3V)
Input Current (A)
Enable and Output Voltage (V)
Typical Characteristics
Time (1µs/div)
7
AAT1265
Low Voltage 2MHz Step-Up DC/DC
Converter in SC70JW Package
Functional Block Diagram
VCC
VIN
Start-Up
Inrush Control
OUT
Low Voltage
Start-Up
VREF
Voltage
Reference
DH
Mode
Control
2MHz
Oscillator
Current
Sense
Comp.
LX
Logic
DL
Error
Amp.
GND
Functional Description
The AAT1265 synchronous step-up converter is
targeted for single- or dual-cell alkaline, NiMH, and
NiCd battery applications. It has a 1V typical startup voltage with operation after start-up to less than
0.8V.
The high 2MHz switching frequency of the
AAT1265 facilitates output filter component size
reduction for improved power density and reduced
overall footprint. It also provides greater bandwidth
and improved transient response over other lower
frequency step-up converters. The compensation
and feedback is integrated with only three external
components (CIN, COUT, L).
Low RDS(ON) synchronous power switches provide
high efficiency for heavy load conditions. Switching
8
EN
GND
frequency modulation and low quiescent current
maintains this high efficiency for light load and
sleep mode conditions.
In addition to the improved efficiency, the synchronous boost has the added performance advantage
of true load disconnect during shutdown (<1µA
shutdown current), inrush current limit, and shortcircuit protection.
PWM / PFM Control
The AAT1265 is a fixed frequency PWM peak current mode control step-up converter. For light load
conditions (10 to 20mA and below), the converter
transitions to a variable frequency (PFM) mode to
reduce the dominant switching losses. In addition
to PFM operation, a zero current comparator
blocks reverse current in the P-channel synchro1265.2006.05.1.1
AAT1265
Low Voltage 2MHz Step-Up DC/DC
Converter in SC70JW Package
nous MOSFET, forcing DCM operation at light load.
These controls, along with very low quiescent current, help to maintain high efficiency over the complete load range without the compromise of
increased output voltage ripple during light load
conditions.
Start-up and Inrush Current Limit
The start-up sequence of the AAT1265 varies
depending upon whether the input voltage is
greater than or less than 2V. Above 1V, a start-up
oscillator operating at 25% duty cycle controls the
synchronous power stage and charges the output
to 2V. For an input voltage greater than 2V, the output is charged at a constant current of 300mA until
the output reaches a voltage level just below the
input voltage. The step-up converter then takes
control and continues to charge the output to the
steady-state voltage. The step-up converter Nchannel switch current is limited to 1A and the typical start-up time is 2.5ms.
Shutdown and Output Disconnect
A typical synchronous step-up (boost) converter
has a conduction path from the input to the output
via the body diode of the P-channel MOSFET. The
AAT1265 design disconnects this body diode from
the output and eliminates this conduction path.
This enables the AAT1265 to provide true load disconnect during shutdown and inrush current limit at
turn-on.
Short-Circuit Protection
The P-channel synchronous MOSFET body diode
disconnect feature also gives the AAT1265 the
ability to provide output short-circuit current limit
protection.
1265.2006.05.1.1
Applications Information
Inductor Selection
The AAT1265 is designed to operate with a 2.2µH
inductor for all input/output voltage combinations.
The inductor saturation current rating should be
greater than the NMOS current limit specification
listed in the Electrical Characteristics table. If necessary, the peak inductor current can exceed the
saturation level by a small amount with no significant effect on performance. Table 1 provides a list
of some suggested inductor manufacturers and
their part numbers.
Output and Input Capacitor Selection
Surface mount X5R or X7R ceramic capacitors are
suggested for both the output and the input. For the
output capacitor (C1 in Figure 4) a 4.7µF, 10V, X5R
ceramic capacitor is necessary for stability, transient response, and ripple performance. The same
0805 sized capacitor is used for the input (C2 of
Figure 4). If desired, a smaller, 0603 sized, 4.7µF,
6.3V, X5R ceramic capacitor can be substituted for
the input capacitor (C2). Suggested ceramic
capacitor suppliers are listed in Table 1.
PCB Layout Guidelines
Figures 1, 2, and 3 display the evaluation board
layout and suggested component placement. Due
to the high switching speed of the AAT1265, it is
important that the evaluation board layout be followed. Even the best switch-mode power supply
design cannot overcome the problems that can be
caused by a poor layout.
For the AAT1265, it is necessary that C1 and C2 be
placed as close as possible to the IC with a good
low impedance path to the GND pins of the IC. It
is also good practice to minimize the length of the
trace from the OUT pin to the output inductor. This
prevents switching noise from radiating into other
high noise sensitive, high impedance circuits.
9
AAT1265
Low Voltage 2MHz Step-Up DC/DC
Converter in SC70JW Package
Figure 1: AAT1265 Evaluation Board
Top Side.
Figure 2: Component Placement.
Figure 3: AAT1265 Evaluation Board
Bottom Side.
VIN
U1
AAT1265
1
2
3
Enable
L1
2.2µH
C2
4.7µF
1
VCC GND
8
2
EN
GND
7
3
VIN
GND
6
4
LX
OUT
5
VOUT
C1
4.7µF
U1 AAT1265 SC70JW-8
L1 SD3118-2R2
C1, C2 4.7µF 10V 0805 X5R
Figure 4: AAT1265 Evaluation Board Schematic.
10
1265.2006.05.1.1
AAT1265
Low Voltage 2MHz Step-Up DC/DC
Converter in SC70JW Package
Manufacturer
Murata
www.murata.com
TDK
www.tdk.com
Taiyo Yuden
www.t-yuden.com
Manufacturer
Sumida
www.sumida.com
Cooper Electronics
www.cooperet.com
Value
Part
Output or Input Capacitor
Input Capacitor
Output or Input Capacitor
Input Capacitor
Output or Input Capacitor
Input Capacitor
4.7µF
4.7µF
4.7µF
Value
Part
2.2µH
2.2µH
Voltage
Case Size
10V
6.3V
10V
6.3V
10V
6.3V
0805
0603
0805
0603
0805
0603
Part Number
GRM21BR61A475KA73L
GRM188R60J475KE19D
C2012X5R1A475K
C1608X5ROJ475K
LMK212BJ475MG
JMK107BJ475MA
ISAT
Voltage
Case Size
Part Number
Inductor
1.50A
75mΩ
3.2 x 3.2 x 1.55
CDRH2D14-2R2
Inductor
1.62A
69mΩ
3.1 x 3.1 x 1.85
SD3118-2R2
Table 1: Suggested Component Selection.
1265.2006.05.1.1
11
AAT1265
Low Voltage 2MHz Step-Up DC/DC
Converter in SC70JW Package
Ordering Information
Voltage
Package
Marking1
Part Number (Tape and Reel)2
3.3V
SC70JW-8
RLXYY
AAT1265IJS-3.3-T1
All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means
semiconductor products that are in compliance with current RoHS standards, including
the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more
information, please visit our website at http://www.analogictech.com/pbfree.
Package Information
SC70JW-8
2.20 ± 0.20
1.75 ± 0.10
0.50 BSC 0.50 BSC 0.50 BSC
0.225 ± 0.075
2.00 ± 0.20
0.100
7° ± 3°
0.45 ± 0.10
4° ± 4°
0.05 ± 0.05
0.15 ± 0.05
1.10 MAX
0.85 ± 0.15
0.048REF
2.10 ± 0.30
All dimensions in millimeters.
1. XYY = assembly and date code.
2. Sample stock is generally held on part numbers listed in BOLD.
12
1265.2006.05.1.1
AAT1265
Low Voltage 2MHz Step-Up DC/DC
Converter in SC70JW Package
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1265.2006.05.1.1
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