ANALOG DEVICES ADP2109 Service Manual
Compact 600 mA, 3 MHz, Step-Down
FEATURES
Peak efficiency: 95%
Discharge switch function
Fixed frequency operation: 3 MHz
Typical quiescent current: 18 μA
Maximum load current: 600 mA
Input voltage: 2.3 V to 5.5 V
Uses tiny multilayer inductors and capacitors
Current mode architecture for fast load and line transient
response
100% duty-cycle low dropout mode
Internal synchronous rectifier
Internal compensation
Internal soft start
Current overload protection
Thermal shutdown protection
Shutdown supply current: 0.2 μA
5-ball WLCSP
APPLICATIONS
PDAs and palmtop computers
Wireless handsets
Digital audio, portable media players
Digital cameras, GPS navigation units
Converter with Output Discharge
ADP2109
GENERAL DESCRIPTION
The ADP2109 is a high efficiency, low quiescent current stepdown dc-to-dc converter with an internal discharge switch that
allows automatic discharge of the output capacitor in an ultrasmall 5-ball WLCSP package.
The total solution requires only three tiny external components.
It uses a proprietary high speed current mode and constant
frequency pulse-width modulation (PWM) control scheme for
excellent stability, and transient response. To ensure the longest
battery life in portable applications, the ADP2109 has a power
save mode that reduces the switching frequency under light
load conditions.
The ADP2109 runs on input voltages of 2.3 V to 5.5 V, which
allow for single lithium or lithium polymer cell, multiple alkaline
or NiMH cells, PCMCIA, USB, and other standard power
sources. The maximum load current of 600 mA is achievable
across the input voltage range.
The ADP2109 is available in fixed output voltages of 1.8 V, 1.5 V,
1.2 V, and 1.0 V. All versions include an internal power switch
and synchronous rectifier for minimal external part count and
high efficiency. The ADP2109 has an internal soft start and internal
compensation. During logic-controlled shutdown, the input is
disconnected from the output and the ADP2109 draws less than
1 A from the input source.
Other key features include undervoltage lockout to prevent deep
battery discharge and soft start to prevent input current overshoot
at startup. The ADP2109 is available in a 5-ball WLCSP.
A similar converter, the ADP2108, provides the same features
and operations as the ADP2109 without the discharge switch
and is available in both WLCSP and TSOT packages with
additional output voltages.
TYPICAL APPLICATIONS CIRCUIT
2.3V TO 5. 5V
4.7µF
OFF
Rev. A
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responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
ON
VIN
ADP2109
EN
GND
Figure 1.
1µH
SW
FB
1.0V TO 1.8V
10µF
07964-001
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700 www.analog.com
Fax: 781.461.3113 ©2009–2010 Analog Devices, Inc. All rights reserved.
ADP2109
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
General Description ......................................................................... 1
Typical Applications Circuit ............................................................ 1
Revision History ............................................................................... 2
Specifications ..................................................................................... 3
Input and Output Capacitor, Recommended Specifications .. 3
Absolute Maximum Ratings ............................................................ 4
Thermal Resistance ...................................................................... 4
ESD Caution .................................................................................. 4
Pin Configuration and Function Descriptions ............................. 5
Typical Performance Characteristics ............................................. 6
Theory of Operation ...................................................................... 10
Control Scheme .......................................................................... 10
PWM Mode ................................................................................. 10
Power Save Mode ........................................................................ 10
Enable/Shutdown ....................................................................... 11
Discharge Switch ........................................................................ 11
Short-Circuit Protection ............................................................ 11
Undervoltage Lockout ............................................................... 11
Thermal Protection .................................................................... 11
Soft Start ...................................................................................... 11
Current Limit .............................................................................. 11
100% Duty Operation ................................................................ 11
Applications Information .............................................................. 12
External Component Selection ................................................ 12
Thermal Considerations ............................................................ 13
PCB Layout Guidelines .............................................................. 13
Evaluation Board ............................................................................ 14
Outline Dimensions ....................................................................... 15
Ordering Guide .......................................................................... 15
REVISION HISTORY
4/10—Rev. 0 to Rev. A
Changes to Ordering Guide .......................................................... 15
4/09—Revision 0: Initial Version
Rev. A | Page 2 of 16
ADP2109
SPECIFICATIONS
VIN = 3.6 V, V
otherwise noted.
Table 1.
Parameters Conditions Min Typ Max Unit
INPUT CHARACTERISTICS
Input Voltage Range 2.3 5.5 V
Undervoltage Lockout Threshold VIN rising 2.3 V
V
OUTPUT CHARACTERISTICS
Output Voltage Accuracy PWM mode −2 +2 %
V
POWER SAVE MODE TO PWM CURRENT THRESHOLD 85 mA
PWM TO POWER SAVE MODE CURRENT THRESHOLD 80 mA
INPUT CURRENT CHARACTERISTICS
DC Operating Current I
Shutdown Current EN = 0 V, TA = TJ = −40°C to +85°C 0.2 1.0 A
SW CHARACTERISTICS
SW On Resistance PFET 320 mΩ
NFET 300 mΩ
Current Limit PFET switch peak current limit 1100 1300 1500 mA
Discharge SW Resistance V
ENABLE CHARACTERISTICS
EN Input High Threshold 1.2 V
EN Input Low Threshold 0.4 V
EN Input Leakage Current EN = 0 V, 3.6 V −1 0 +1 A
OSCILLATOR FREQUENCY I
START-UP TIME 550 s
THERMAL CHARACTERISTICS
Thermal Shutdown Threshold 150 °C
Thermal Shutdown Hysteresis 20 °C
1
All limits at temperature extremes are guaranteed via correlation using standard statistical quality control (SQC).
= 1.8 V, TJ = −40°C to +125°C for minimum/maximum specifications, and TA = 25°C for typical specifications, unless
OUT
1
falling 2.05 2.15 2.25 V
IN
= 2.3 V to 5.5 V, PWM mode −2.5 +2.5 %
IN
= 0 mA, device not switching 18 30 A
LOAD
= 1.0 V 150 Ω
OUT
= 200 mA 2.5 3.0 3.5 MHz
LOAD
INPUT AND OUTPUT CAPACITOR, RECOMMENDED SPECIFICATIONS
Table 2.
Parameter Symbol Conditions Min Typ Max Unit
MINIMUM INPUT AND OUTPUT CAPACITANCE C
MINIMUM AND MAXIMUM INDUCTANCE L TA = −40°C to +125°C 0.3 3.0 µH
T
MIN
Rev. A | Page 3 of 16
= −40°C to +125°C 4.7 µF
A
ADP2109
ABSOLUTE MAXIMUM RATINGS
Table 3.
Parameter Rating
VIN, EN −0.4 V to +6.5 V
FB, SW to GND −1.0 V to (VIN + 0.2 V)
Operating Ambient Temperature Range −40°C to +85°C
Operating Junction Temperature Range −40°C to +125°C
Storage Temperature Range −65°C to +150°C
Lead Temperature Range −65°C to +150°C
Soldering Conditions JEDEC J-STD-020
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
Absolute maximum ratings apply individually only, not in
combination. Unless otherwise specified, all other voltages are
referenced to GND.
The ADP2109 can be damaged when the junction temperature
limits are exceeded. Monitoring ambient temperature does not
guarantee that the junction temperature (T
) is within the specified
J
temperature limits. In applications with high power dissipation
and poor thermal resistance, the maximum ambient temperature may have to be derated. In applications with moderate
power dissipation and low PCB thermal resistance, the maximum ambient temperature can exceed the maximum limit
as long as T
dependent on the ambient temperature (T
is within specification limits. TJ of the device is
J
) of the device,
A
the power dissipation (PD) of the device, and the junction-toambient thermal resistance (θ
is calculated from T
= TA + (PD × θJA)
T
J
and PD using the following formula:
A
) of the package. Maximum TJ
JA
THERMAL RESISTANCE
θJA is specified for a device mounted on a JEDEC 2S2P PCB.
Table 4. Thermal Resistance
Package Type θJA Unit
5-Ball WLCSP 105 °C/W
ESD CAUTION
Rev. A | Page 4 of 16
ADP2109
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
BALLA1
INDICATOR
1
2
VIN GND
A
SW
B
EN FB
C
TOP VIEW
(BALL SIDE DOW N)
Not to Scale
Figure 2. Pin Configuration
Table 5. Pin Function Descriptions
Pin No. Mnemonic Description
A1 VIN
Power Source Input. VIN is the source of the PFET high-side switch. Bypass VIN to GND with a 2.2 F or greater
capacitor as close to the ADP2109 as possible.
A2 GND Ground. Connect all the input and output capacitors to GND.
B SW Switch Node Output. SW is the drain of the PFET switch and NFET synchronous rectifier.
C1 EN Enable Input. Drive EN high to turn on the ADP2109. Drive EN low to turn it off and reduce the input current to 0.1 A.
C2 FB Feedback Input of the Error Amplifier. Connect FB to the output of the switching regulator.
07964-003
Rev. A | Page 5 of 16
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