AME AME5172 0.85v single cell boost dc-dc converter Datasheet

AME, Inc.
0.85V Single Cell Boost
DC-DC Converter
AME5172
n General Description
The AME5172 is a high-efficiency, current mode, synchronous PWM Boost DC-DC Converter with fixed 3.3V
output voltage for system applications powered by single
or double cell NiMH or Alkaline battery pack.
Built-in 0.35Ω NMOS switch and 0.45Ω PMOS synchronous rectification significantly improves efficiency and
reduces external components count. High switching frequency (at 1.2MHz) allows easy filtering and faster loop
performance.
AME5172 uses SOT-25 package that gives a small size
solution.
n Typical Application
L1
4.7µH
VIN
CIN
4.7µF
1
IN
SW
5
AME5172
OUT
OFF ON
3
EN
GND
4
2
VOUT 3.3V
up to 200mA
COUT
4.7µF
n Features
l PWM Control with 1.2MHz Fixed Frequency
l Up to 92% Efficiency
l 0.85V Low Start-up Input Voltage
l Internal Synchronous Rectifier
l Fixed 3.3V Output Voltage Options
l 0.8A, 0.35Ω Power MOSFET
l 1µA Shutdown Current
l True Shutdown
l SOT-25 Package
l All AME's Lead Free Products Meet RoHS
Standards
n Applications
l Hand-held Devices
l Digital Cameras
l Portable Applications
l MP3 Players
l LCD Bias Power
l Wireless Handsets
Rev. A.02
1
AME, Inc.
0.85V Single Cell Boost
DC-DC Converter
AME5172
n Function Block Diagram
IN
EN
SW
Enable
VOUT
Good
Start-UP
OSC
Bandgap
2.3V
OUT
Erroramp
Σ
PWM
COMP
PWM
Control
SYNC
Driver
OSC
Ramp
Current
Limit
COMP
Current
sense
GND
2
Rev. A.02
AME, Inc.
0.85V Single Cell Boost
DC-DC Converter
AME5172
n Pin Configuration
SOT-25
Top View
5
4
AME5172AEEV
1. IN
2. GND
AME5172
3. EN
4. OUT
5. SW
1
2
3
* Die Attach:
Conductive Epoxy
n Pin Description
Pin Number
Pin Name
1
IN
2
GND
3
EN
4
OUT
Power Output Pin.
PCB layout from output capacitor should be as short and wide as
possible..
5
SW
This is the switch pin and is connected to the drain of the internal NMOS
power switch. Minimize the metal trace area connected to this pin to
minimize EMI.
Rev. A.02
Pin Description
Input Supply Pin.
Place bypass capacitor as close to VIN as possible.
Ground connection Pin.
Enable Control Input Pin. (Active High)
3
AME, Inc.
0.85V Single Cell Boost
DC-DC Converter
AME5172
n Ordering Information
AME5172 x x x x xxx x
Special Feature
Output Voltage
Number of Bumps
Package Type
Operating Ambient Temperature Range
Pin Configuration
Pin
Configuration
A
(SOT-25)
1. IN
2. GND
3. EN
4. OUT
5. SW
Operating Ambient
Temperature Range
Package Type
Number
of
Pins
Output Voltage
Special Feature
E: -40OC to 85OC
E: SOT-2x
V: 5
330: 3.3V
Z:
Lead free
n Ordering Information
Part Number
Marking*
Output Voltage
Package
Operating Ambient
Temperature Range
AME5172AEEV330Z
BTWww
3.3V
SOT-25
-40OC to 85OC
Note: ww represents the date code and pls refer to Date Code Rule on Package Dimension.
* A line on top of the first letter represents lead free plating such as BTW.
Please consult AME sales office or authorized Rep./Distributor for the availability of package type.
4
Rev. A.02
AME, Inc.
0.85V Single Cell Boost
DC-DC Converter
AME5172
n Absolute Maximum Ratings
Parameter
Symbol
Maximum
Unit
V IN
-0.3 to 6
V
VEN ,VOUT
-0.3 to 6
V
VSW
-0.3 to 6
V
Input Voltage
EN, Output Voltages
Switch Voltage
B*
ESD Classification
Caution: Stress above the listed absolute maximum rating may cause permanent damage to the device.
* HBM B:2000V~3999V exclude SW pin.
n Recommended Operating Conditions
Parameter
Symbol
Rating
Ambient Temperature Range
TA
-40 to 85
Junction Temperature Range
TJ
-40 to 125
Storage Temperature Range
TSTG
-65 to 150
Unit
o
C
n Thermal Information
Parameter
Package
Die Attach
Thermal Resistance*
(Junction to Case)
Symbol
Maximum
θJC
81
Unit
o
Thermal Resistance
(Junction to Ambient)
SOT-25
Conductive Epoxy
Internal Power Dissipation
Solder Iron (10Sec)**
θJA
260
PD
400
350
C/W
mW
o
C
* Measure θJC on backside center of molding compund if IC has no tab.
** MIL-STD-202G 210F
Rev. A.02
5
AME, Inc.
0.85V Single Cell Boost
DC-DC Converter
AME5172
n Electrical Specifications
VIN = 1.2 V, EN = VIN, VOUT=3.3V, TA = 25OC unless otherwise noted.
Parameter
Input Voltage
Output Voltage
Minimum Start-Up Voltage
Symbol
Test Condition
Min
V IN
0.85
V OUT
3.217
Typ
Max
Units
Note 1
3.3
3.383
V ST
ILOAD = 1mA
Quiescent Current
IQ
Measured on VOUT
500
Shutdown Current
ISD
EN = GND
1
NMOS Switch Current Limit
ICL
V
0.85
600
800
NMOS Switch RDSON
RON,N
VOUT = 3.3V
0.35
PMOS Switch RDSON
RON,P
VOUT = 3.3V
0.45
Switching Frequency
fSW
0.85
1.2
Maximum Duty Cycle
DMAX
80
87
µA
mA
Ω
1.5
MHz
%
EN Input Current
IEN
EN = GND or VIN
1
µA
N/PMOS Leakage Current
ISW
VSW = 5V for NMOS, 0V for PMOS
5
µA
EN Input Threshold (High)
(Enable the device)
EN Input Threshold (Low)
(Shutdown)
EN
Threshold
1
VIN
V
0.35
Note 1: VIN<VOUT
6
Rev. A.02
AME, Inc.
0.85V Single Cell Boost
DC-DC Converter
AME5172
n Detailed Description
n Application Information
The AME5172 is a fixed frequency synchronous boost
converter in SOT-25 package. The feature include current
mode PWM control with internal frequency compensation, low RDS(ON) MOSFET switch, synchronous rectification and 800mA peak switching current limit.
Inductor Selection
Synchronous Rectification
Built-in 0.35Ω NMOS switch and 0.45Ω PMOS synchronous rectification significantly improves efficiency and
eliminates the need for an external Schottky diode. High
switching frequency (at 1.2MHz) also allows easy filtering and faster loop performance.
Low Voltage Start-Up
The AME5172 will start-up at typical input voltage of
0.85V. At start-up, switching frequency is determined by
the start-up oscillator and start-up current limit. When
VOUT exceeds 2.3V, the start-up circuit will disabled and
the PWM mode is initiated.
An inductor value of 4.7µH performs well in most application. Larger values of inductance can reduce the inductor ripple current. Choosing inductors with low ESR decrease power loss and increase efficiency.
The approximate output current capability versus inductance value is given in the equation below:

V ×D 
I OUT (max) = η (1 − D ) I CL − IN

2 × L × f SW 

where:
η = efficiency
D=
VOUT − VIN
VOUT
ICL=switching peak current limit
VIN=input voltage
L=inductance value
FSW =switching frequency
Output Capacitor Selection
Thermal Shutdown Protection
The AME5172 has thermal shutdown protection at
160OC (Typ.). If the device temperature rises above 160OC,
the internal power MOSFET will turn off. Once the temperature falls below 140OC, the device resumes normal
operation. However, device functionality is only guaranteed to a maximum junction temperature of +125OC.
A single ceramic capacitor of value 4.7µF to 10µF will
provide sufficient output capacitance for most applications.
Larger capacitance with low ESR can be used to improve
ripple and transient response.
An output capacitor with excessive ESR can also reduce phase margin and cause instability. In general, if
electrolytic are used, it is recommended to parallel with
ceramic capacitors to reduce ringing, switching losses,
and output voltage ripple.
Input Capacitor Selection
An input capacitor is required to serve as an energy reservoir for the current which must flow into the coil each
time the switch turns ON. This capacitor must have extremely low ESR, so ceramic is the best choice. We recommend a nominal value of 4.7µF, but larger values can
be used. Since this capacitor reduces the amount of voltage ripple seen at the input pin, it also reduces the amount
of EMI passed back to other circuitry.
Rev. A.02
7
AME, Inc.
0.85V Single Cell Boost
DC-DC Converter
AME5172
VOUT vs Temperature
Star-up Voltage vs Load Current
1.4
3.377
3.357
Start-up Voltage (V)
1.3
VOUT (V)
3.337
3.317
3.297
3.277
3.257
1.2
1.1
1.0
0.9
3.237
3.217
-40
-20
0
20
40
o
60
0.8
0.1
80
1
10
100
Temperature ( C)
IOUT (mA)
Output Voltage vs Load Current
Normalized Frequency vs Temperature
3.377
3.357
Frequency (MHz)
1.40
3.337
VIN = 2.4V
VOUT
3.317
3.297
VIN = 1.2V
VIN = 1.5V
3.277
3.257
1.29
1.18
1.07
0.96
3.237
3.217
0.1
1
10
100
0.85
-40
1000
60
80
900
850
70
60
VIN = 1.5V
VIN = 2.4V
40
30
VIN = 1.2V
Current Limit (mA)
Efficiency (%)
40
Current Limit vs Temperature
80
800
750
700
650
600
20
1
10
100
Load Current (mA)
8
20
Efficiency vs Load Current
90
10
0
0
Temperature (oC)
100
50
-20
Load Current (mA)
1000
550
-40
-20
0
20
40
60
80
Temperature (oC)
Rev. A.02
AME, Inc.
0.85V Single Cell Boost
DC-DC Converter
AME5172
SW Pin Operation
VOUT(AC)
VOUT Transient Response
VSW
1V/Div
100mV/Div
100mA
IOUT
0V
100ns/Div
VIN = 1.3V
VOUT = 3.3V
IOUT = 10mA
L = 6.8µH
COUT = 4.7µF
40mA
100ns/Div
VIN = 1.3V
VOUT = 3.3V
IOUT = 40mA to 100mA
L = 6.8µH
COUT = 4.7µF
SW Pin Fixed Frequency Continuous
Inductor Current Operation
VSW
1V/Div
0V
100ns/Div
VIN = 1.3V
VOUT = 3.3V
IOUT = 50mA
L = 6.8µH
COUT = 4.7µF
Rev. A.02
9
AME, Inc.
0.85V Single Cell Boost
DC-DC Converter
AME5172
n Date Code Rule
Marking
Date Code
Year
A
A
A
W
W
xxx0
A
A
A
W
W
xxx1
A
A
A
W
W
xxx2
A
A
A
W
W
xxx3
A
A
A
W
W
xxx4
A
A
A
W
W
xxx5
A
A
A
W
W
xxx6
A
A
A
W
W
xxx7
A
A
A
W
W
xxx8
A
A
A
W
W
xxx9
n Tape and Reel Dimension
SOT-25
P
W
AME
AME
PIN 1
Carrier Tape, Number of Components Per Reel and Reel Size
10
Package
Carrier Width (W)
Pitch (P)
Part Per Full Reel
Reel Size
SOT-25
8.0±0.1 mm
4.0±0.1 mm
3000pcs
180±1 mm
Rev. A.02
AME, Inc.
0.85V Single Cell Boost
DC-DC Converter
AME5172
n Package Dimension
SOT-25
Top View
Side View
SYMBOLS
D
MILLIMETERS
MAX
MIN
MAX
L
MIN
INCHES
E
H
A
θ1
S1
0.00
0.15
0.0000
0.0059
b
0.30
0.55
0.0118
0.0217
D
2.70
3.10
0.1063
0.1220
E
1.40
1.80
0.0551
0.0709
e
L
Front View
A
θ1
Rev. A.02
S1
1.90 BSC
2.60
3.00
0.37BSC
0o
10 o
0.95BSC
0.07480 BSC
0.10236 0.11811
0.0146BSC
0o
10 o
0.0374BSC
A1
b
0.0472REF
A1
H
e
1.20REF
11
www.ame.com.tw
E-Mail: [email protected]
Life Support Policy:
These products of AME, Inc. are not authorized for use as critical components in life-support
devices or systems, without the express written approval of the president
of AME, Inc.
AME, Inc. reserves the right to make changes in the circuitry and specifications of its devices and
advises its customers to obtain the latest version of relevant information.
 AME, Inc. , September 2007
Document: 1233-DS5172-A.02
Corporate Headquarter
U.S.A. (Subsidiary)
AME, Inc.
Analog Microelectronics, Inc.
2F, 302 Rui-Guang Road, Nei-Hu District
Taipei 114, Taiwan.
3100 De La Cruz Blvd., Suite 201
Santa Clara, CA. 95054-2438
Tel: 886 2 2627-8687
Fax: 886 2 2659-2989
Tel : (408) 988-2388
Fax: (408) 988-2489
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