Data Sheet
FEATURES
Extremely high 97% efficiency
Ultralow quiescent current: 20 μA
1.2 MHz switching frequency
0.1 μA shutdown supply current
Maximum load current
ADP2105: 1 A
ADP2106: 1.5 A
ADP2107: 2 A
Input voltage: 2.7 V to 5.5 V
Output voltage: 0.8 V to V
IN
Maximum duty cycle: 100%
Smoothly transitions into low dropout (LDO) mode
Internal synchronous rectifier
Small 16-lead 4 mm × 4 mm LFCSP_VQ package
Optimized for small ceramic output capacitors
Enable/shutdown logic input
Undervoltage lockout
Soft start
Supported by
ADIsimPower™
design tool
1 Amp/1.5 Amp/2 Amp Synchronous,
Step-Down DC-to-DC Converters
ADP2105/ADP2106/ADP2107
GENERAL DESCRIPTION
The ADP2105/ADP2106/ADP2107 are low quiescent current,
synchronous, step-down dc-to-dc converters in a compact 4 mm ×
4 mm LFCSP_VQ package. At medium to high load currents,
these devices use a current mode, constant frequency pulse-
width modulation (PWM) control scheme for excellent stability
and transient response. To ensure the longest battery life in portable
applications, the ADP2105/ADP2106/ADP2107 use a pulse
frequency modulation (PFM) control scheme under light load
conditions that reduces switching frequency to save power.
The ADP2105/ADP2106/ADP2107 run from input voltages of
2.7 V to 5.5 V, allowing single Li+/Li− polymer cell, multiple
alkaline/NiMH cells, PCMCIA, and other standard power sources.
The output voltage of ADP2105/ADP2106/ADP2107 is adjustable
from 0.8 V to the input voltage (indicated by ADJ), whereas the
ADP2105/ADP2106/ADP2107 are available in preset output
voltage options of 3.3 V, 1.8 V, 1.5 V, and 1.2 V (indicated by x.x V).
Each of these variations is available in three maximum current
levels: 1 A (ADP2105), 1.5 A (ADP2106), and 2 A (ADP2107). The
power switch and synchronous rectifier are integrated for minimal
external part count and high efficiency. During logic controlled
shutdown, the input is disconnected from the output, and it
draws less than 0.1 µA from the input source. Other key features
include undervoltage lockout to prevent deep battery discharge
and programmable soft start to limit inrush current at startup.
APPLICATIONS
Mobile handsets
PDAs and palmtop computers
Telecommunication/networking equipment
Set top boxes
Audio/video consumer electronics
TYPICAL OPERATING CIRCUIT
0.1μF
10Ω
V
IN
INPUT VOLTAGE = 2.7V TO 5.5V
10μF
FB
16
15
14
13
100
V
IN
= 3.3V
95
V
IN
= 3.6V
V
OUT
= 2.5V
ON
OFF
1
FB
EN
GND
GND
GND
COMP
5
GND
IN
PWIN1
2μH
EFFICIENCY (%)
LX2
12
PGND
11
OUTPUT VOLTAGE = 2.5V
90
V
IN
= 5V
85
2
ADP2107-ADJ
3
85kΩ
LX1
10
FB
V
IN
40kΩ
10μF
10μF
4.7μF
4
PWIN2
9
SS
6
AGND NC
7
8
LOAD
0A TO 2A
80
06079-001
70kΩ
120pF
1nF
75
06079-002
0
200
400
600
800
1000 1200 1400 1600 1800 2000
NC = NO CONNECT
LOAD CURRENT (mA)
Figure 1. Circuit Configuration of ADP2107 with V
OUT
= 2.5 V
Figure 2. Efficiency vs. Load Current for the ADP2107 with V
OUT
= 2.5 V
Rev. D
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
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.
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 ©2006–2012 Analog Devices, Inc. All rights reserved.
ADP2105/ADP2106/ADP2107
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
General Description ......................................................................... 1
Typical Operating Circuit ................................................................ 1
Revision History ............................................................................... 2
Functional Block Diagram .............................................................. 3
Specifications..................................................................................... 4
Absolute Maximum Ratings ............................................................ 6
Thermal Resistance ...................................................................... 6
Boundary Condition .................................................................... 6
ESD Caution .................................................................................. 6
Pin Configuration and Function Descriptions ............................. 7
Typical Performance Characteristics ............................................. 8
Theory of Operation ...................................................................... 14
Control Scheme .......................................................................... 14
PWM Mode Operation .............................................................. 14
PFM Mode Operation................................................................ 14
Pulse-Skipping Threshold ......................................................... 14
100% Duty Cycle Operation (LDO Mode) ............................. 14
Slope Compensation .................................................................. 15
Design Features ........................................................................... 15
Applications Information .............................................................. 16
Data Sheet
External Component Selection ................................................ 16
Setting the Output Voltage ........................................................ 16
Inductor Selection ...................................................................... 17
Output Capacitor Selection....................................................... 18
Input Capacitor Selection .......................................................... 19
Input Filter................................................................................... 19
Soft Start Period .......................................................................... 19
Loop Compensation .................................................................. 19
Bode Plots .................................................................................... 20
Load Transient Response .......................................................... 21
Efficiency Considerations ......................................................... 22
Thermal Considerations............................................................ 22
Design Example .............................................................................. 24
External Component Recommendations .................................... 25
Circuit Board Layout Recommendations ................................... 27
Evaluation Board ............................................................................ 28
Evaluation Board Schematic for ADP2107 (1.8 V) ............... 28
Recommended PCB Board Layout (Evaluation Board
Layout) ......................................................................................... 28
Application Circuits ....................................................................... 30
Outline Dimensions ....................................................................... 33
Ordering Guide .......................................................................... 33
Changes to Slope Compensation Section.................................... 15
Changes to Setting the Output Voltage Section ........................ 16
Changes to Figure 37...................................................................... 16
Changes to Inductor Selection Section........................................ 17
Changes to Input Capacitor Selection Section ........................... 18
Changes to Figure 47 through Figure 52 ..................................... 21
Changes to Transition Losses Section and Thermal
Considerations Section .................................................................. 22
Changes to Table 11 ....................................................................... 25
Changes to Circuit Board Layout Recommendations Section..27
Changes to Table 12 ....................................................................... 26
Changes to Figure 53...................................................................... 28
Changes to Figure 56 Through Figure 57.................................... 30
Changes to Figure 58 Through Figure 59.................................... 31
Changes to Outline Dimensions .................................................. 33
3/07—Rev. 0 to Rev. A
Updated Format .................................................................. Universal
Changes to Output Characteristics and
LX (Switch Node) Characteristics Sections ...................................3
Changes to Typical Performance Characteristics Section ...........7
Changes to Load Transient Response Section ............................ 21
7/06—Revision 0: Initial Version
REVISION HISTORY
8/12—Rev. C to Rev. D
Change to Features Section ............................................................. 1
Added Exposed Pad Notation to Pin Configuration and
Function Description Section ......................................................... 7
Added ADIsimPower Design Tool Section ................................. 16
Updated Outline Dimensions ....................................................... 33
9/08—Rev. B to Rev. C
Changes to Table Summary Statement .......................................... 4
Changes to LX Minimum On-Time Parameter, Table 1 ............. 5
7/08—Rev. A to Rev. B
Changes to General Description Section ...................................... 1
Changes to Figure 3 .......................................................................... 3
Changes to Table 1 ............................................................................ 4
Changes to Table 2 ............................................................................ 6
Changes to Figure 4 .......................................................................... 7
Changes to Table 4 ............................................................................ 7
Changes to Figure 26 ...................................................................... 11
Changes to Figure 31 Through Figure 34 .................................... 12
Changes to Figure 35 ...................................................................... 13
Changes to PMW Mode Operation Section and Pulse Skipping
Threshold Section ........................................................................... 14
Rev. D | Page 2 of 36
Data Sheet
FUNCTIONAL BLOCK DIAGRAM
COMP
5
ADP2105/ADP2106/ADP2107
14
IN
PWIN2
PWIN1
SS
6
SOFT
START
REFERENCE
0.8V
9
CURRENT SENSE
AMPLIFIER
13
FB
16
FB
16
GM ERROR
AMP
PWM/
PFM
CONTROL
CURRENT
LIMIT
AGND
7
FOR PRESET
VOLTAGE
OPTIONS ONLY
GND
2
GND
3
GND
4
DRIVER
AND
ANTI-
SHOOT
THROUGH
10
12
LX1
LX2
SLOPE
COMPENSATION
NC
8
GND
15
OSCILLATOR
ZERO CROSS
COMPARATOR
EN
1
THERMAL
SHUTDOWN
11
PGND
Figure 3.
Rev. D | Page 3 of 36
06079-037
ADP2105/ADP2106/ADP2107
SPECIFICATIONS
Table 1.
Parameter
INPUT CHARACTERISTICS
Input Voltage Range
Undervoltage Lockout Threshold
Min
2.7
2.4
2.2
2.2
2.0
Undervoltage Lockout Hysteresis
OUTPUT CHARACTERISTICS
Output Regulation Voltage
2
Data Sheet
V
IN
=
3.6 V @ T
A
= 25°C, unless otherwise noted.
1
Typ
Max
5.5
2.6
2.5
200
3.267
3.201
1.782
1.746
1.485
1.455
1.188
1.164
Load Regulation
0.4
0.5
0.6
0.1
0.1
0.8
0.8
0.784
−0.1
3
6
4
8
5
10
10
20
0.816
+0.1
1.2
1.2
1.5
1.5
1.8
1.8
3.3
3.3
3.333
3.399
1.818
1.854
1.515
1.545
1.212
1.236
Unit
V
V
V
V
V
mV
V
V
V
V
V
V
V
V
V
V
V
V
%/A
%/A
%/A
%/V
%/V
V
V
V
µA
µA
µA
µA
µA
µA
µA
µA
µA
Conditions
−40°C ≤ T
J
≤ +125°C
V
IN
rising
V
IN
rising, −40°C ≤ T
J
≤ +125°C
V
IN
falling
V
IN
falling, −40°C ≤ T
J
≤ +125°C
V
IN
falling
3.3 V, load = 10 mA
3.3 V, V
IN
= 3.6 V to 5.5 V, no load to full load
3.3 V, V
IN
= 3.6 V to 5.5 V, no load to full load,
−40°C ≤ T
J
≤ +125°C
1.8 V, load = 10 mA
1.8 V, V
IN
= 2.7 V to 5.5 V, no load to full load
1.8 V, V
IN
= 2.7 V to 5.5 V, no load to full load,
−40°C ≤ T
J
≤ +125°C
1.5, load = 10 mA
ADP210x-1.5 V, V
IN
= 2.7 V to 5.5 V, no load to full load
ADP210x-1.5 V, V
IN
= 2.7 V to 5.5 V, no load to full load,
−40°C ≤ T
J
≤ +125°C
1.2 V, load = 10 mA
1.2 V, V
IN
= 2.7 V to 5.5 V, no load to full load
1.2 V, V
IN
= 2.7 V to 5.5 V, no load to full load,
−40°C ≤ T
J
≤ +125°C
ADP2105
ADP2106
ADP2107
ADP2105, measured in servo loop
ADP2106 and ADP2107, measured in servo loop
ADJ
ADJ
ADJ, −40°C ≤ T
J
≤ +125°C
ADJ, −40°C ≤ T
J
≤ +125°C
1.2 V output voltage
1.2 V output voltage, −40°C ≤ T
J
≤ +125°C
1.5 V output voltage
1.5 V output voltage, −40°C ≤ T
J
≤ +125°C
1.8 V output voltage
1.8 V output voltage, −40°C ≤ T
J
≤ +125°C
3.3 V output voltage
3.3 V output voltage, −40°C ≤ T
J
≤ +125°C
Line Regulation
3
Output Voltage Range
FEEDBACK CHARACTERISTICS
FB Regulation Voltage
FB Bias Current
0.33
0.3
V
IN
Rev. D | Page 4 of 36
Data Sheet
Parameter
INPUT CURRENT CHARACTERISTICS
IN Operating Current
Min
Typ
20
30
20
30
IN Shutdown Current
4
LX (SWITCH) NODE CHARACTERISTICS
LX On Resistance
4
0.1
190
270
100
165
160
230
90
140
LX Leakage Current
4, 5
LX Peak Current Limit
5
2.6
2.25
2.0
1.5
1.3
LX Minimum On-Time
ENABLE CHARACTERISTICS
EN Input High Voltage
EN Input Low Voltage
EN Input Leakage Current
OSCILLATOR FREQUENCY
SOFT START PERIOD
THERMAL CHARACTERISTICS
Thermal Shutdown Threshold
Thermal Shutdown Hysteresis
COMPENSATOR
TRANSCONDUCTANCE (g
m
)
CURRENT SENSE AMPLIFIER GAIN (G
CS
)
2
1
750
1.8
110
2.6
0.1
2.9
1
3.3
1
Max
Unit
µA
µA
µA
µA
µA
mΩ
mΩ
mΩ
mΩ
mΩ
mΩ
mΩ
mΩ
µA
A
A
A
A
A
A
ns
V
V
µA
µA
MHz
MHz
µs
°C
°C
µA/V
A/V
A/V
A/V
ADP2105
ADP2106
ADP2107
Conditions
ADP2105/ADP2106/ADP2107
ADP210x(ADJ), V
FB
= 0.9 V
ADP210x(ADJ), V
FB
= 0.9 V, −40°C ≤ T
J
≤ +125°C
ADP210x(x.x V) output voltage 10% above regulation
voltage
ADP210x(x.x V) output voltage 10% above regulation
voltage, −40°C ≤ T
J
≤ +125°C
V
EN
= 0 V
P-channel switch, ADP2105
P-channel switch, ADP2105, −40°C ≤ T
J
≤ +125°C
P-channel switch, ADP2106 and ADP2107
P-channel switch, ADP2106 and ADP2107,
−40°C ≤ T
J
≤ +125°C
N-channel synchronous rectifier, ADP2105
N-channel synchronous rectifier, ADP2105,
−40°C ≤ T
J
≤ +125°C
N-channel synchronous rectifier, ADP2106 and ADP2107
N-channel synchronous rectifier, ADP2106 and ADP2107,
−40°C ≤ T
J
≤ +125°C
V
IN
= 5.5 V, V
LX
= 0 V, 5.5 V
P-channel switch, ADP2107
P-channel switch, ADP2107, −40°C ≤ T
J
≤ +125°C
P-channel switch, ADP2106
P-channel switch, ADP2106, −40°C ≤ T
J
≤ +125°C
P-channel switch, ADP2105
P-channel switch, ADP2105, −40°C ≤ T
J
≤ +125°C
In PWM mode of operation, −40°C ≤ T
J
≤ +125°C
V
IN
= 2.7 V to 5.5 V, −40°C ≤ T
J
≤ +125°C
V
IN
= 2.7 V to 5.5 V, −40°C ≤ T
J
≤ +125°C
V
IN
= 5.5 V, V
EN
= 0 V, 5.5 V
V
IN
= 5.5 V, V
EN
= 0 V, 5.5 V, −40°C ≤ T
J
≤ +125°C
V
IN
= 2.7 V to 5.5 V
V
IN
= 2.7 V to 5.5 V, −40°C ≤ T
J
≤ +125°C
C
SS
= 1 nF
2
0.4
−0.1
−1
1.2
1000
140
40
50
1.875
2.8125
3.625
1.4
1200
+1
1
2
All limits at temperature extremes are guaranteed via correlation using standard statistical quality control (SQC). Typical values are at T
A
= 25°C.
Guaranteed by design.
3
The ADP2105/ADP2106/ADP2107 line regulation was measured in a servo loop on the automated test equipment that adjusts the feedback voltage to achieve a
specific COMP voltage.
4
All LX (switch) node characteristics are guaranteed only when the LX1 pin and LX2 pin are tied together.
5
These specifications are guaranteed from −40°C to +85°C.
Rev. D | Page 5 of 36
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