1 A, Low Dropout,
CMOS Linear Regulator
ADP1706/ADP1707/ADP1708
FEATURES
Maximum output current: 1 A
Input voltage range: 2.5 V to 5.5 V
Low shutdown current: <1 μA
Low dropout voltage: 345 mV @ 1 A load
Initial accuracy: ±1%
Accuracy over line, load, and temperature: ±2.5%
16 fixed output voltage options with soft start:
0.75 V to 3.3 V (ADP1706)
16 fixed output voltage options with tracking
0.75 V to 3.3 V (ADP1707)
Adjustable output voltage option:
0.8 V to 5.0 V (ADP1708)
Stable with small 4.7 μF ceramic output capacitor
Excellent load/line transient response
Current limit and thermal overload protection
Logic-controlled enable
Available in an 8-lead, exposed paddle SOIC and
3 mm × 3 mm, 8-lead exposed paddle LFCSP
TYPICAL APPLICATION CIRCUITS
ADP1706
1
2
10nF
EN
GND
IN
IN
SS
8
SENSE
7
OUT
6
OUT
5
4.7µF
V
OUT
= 3.3V
06640-001
V
IN
= 5V
4.7µF
3
4
Figure 1. ADP1706 with Fixed Output Voltage, 3.3 V
ADP1707
1
2
EN
GND
IN
IN
TRK
8
SENSE
7
OUT
6
OUT
5
V
TRK
V
OUT
4.7µF
V
IN
= 5V
4.7µF
3
4
V
OUT
(V)
3
2
1
0
1 2 3 4 5
V
TRK
(V)
06640-003
APPLICATIONS
Notebook computers
Memory components
Telecommunications equipment
Network equipment
DSP/FPGA/microprocessor supplies
Instrumentation equipment/data acquisition systems
Figure 2. ADP1707 with Output Voltage Tracking
ADP1708
1
2
R2
8
EN
GND
IN
IN
ADJ
R1
V
OUT
= 0.8V(1 + R1/R2)
06640-002
SENSE
7
OUT
6
OUT
5
V
IN
= 5V
4.7µF
3
4
4.7µF
Figure 3. ADP1708 with Adjustable Output Voltage, 0.8 V to 5.0 V
GENERAL DESCRIPTION
The ADP1706/ADP1707/ADP1708 are CMOS, low dropout
linear regulators that operate from 2.5 V to 5.5 V and provide
up to 1 A of output current. Using an advanced proprietary
architecture, they provide high power supply rejection and
achieve excellent line and load transient response with a small
4.7 μF ceramic output capacitor.
The ADP1706/ADP1707 are available in 16 fixed output volt-
age options. The ADP1708 is available in an adjustable version,
which allows output voltages that range from 0.8 V to 5.0 V via
an external divider. The ADP1706 allows an external soft start
capacitor to be connected to program the start-up time; the
ADP1707 and ADP1708 contain internal soft start capacitors
that give a typical start-up time of 100 μs. The ADP1707
includes a tracking feature that allows the output to follow an
external voltage rail or reference.
The ADP1706/ADP1707/ADP1708 are available in an 8-lead,
exposed paddle SOIC package and an 8-lead, 3 mm × 3 mm
exposed paddle LFCSP, making them not only very compact
solutions but also providing excellent thermal performance for
applications requiring up to 1 A of output current in a small,
low profile footprint.
Rev. 0
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
©2007 Analog Devices, Inc. All rights reserved.
ADP1706/ADP1707/ADP1708
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications....................................................................................... 1
Typical Application Circuits............................................................ 1
General Description ......................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 5
Thermal Resistance ...................................................................... 5
ESD Caution.................................................................................. 5
Pin Configurations and Function Descriptions ........................... 6
Typical Performance Characteristics ............................................. 7
Theory of Operation ...................................................................... 10
Soft Start Function (ADP1706) ................................................ 10
Adjustable Output Voltage (ADP1708)................................... 11
Track Mode (ADP1707) ............................................................ 11
Enable Feature ............................................................................ 11
Application Information................................................................ 12
Capacitor Selection .................................................................... 12
Voltage Tracking Applications.................................................. 12
Current Limit and Thermal Overload Protection ................. 12
Thermal Considerations............................................................ 13
PCB Layout Considerations...................................................... 15
Outline Dimensions ....................................................................... 16
Ordering Guide .......................................................................... 17
REVISION HISTORY
6/07—Revision 0: Initial Version
Rev. 0 | Page 2 of 20
ADP1706/ADP1707/ADP1708
SPECIFICATIONS
V
IN
= (V
OUT
+ 0.6 V) or 2.5 V (whichever is greater), I
OUT
= 10 mA, C
IN
= C
OUT
= 4.7 μF, T
A
= 25°C, unless otherwise noted.
Table 1.
Parameter
INPUT VOLTAGE RANGE
OPERATING SUPPLY CURRENT
Symbol
V
IN
I
GND
Test Conditions
T
J
= –40°C to +125°C
I
OUT
= 0 mA
I
OUT
= 100 mA
I
OUT
= 100 mA, T
J
= −40°C to +125°C
I
OUT
= 1 A
I
OUT
= 1 A, T
J
= −40°C to +125°C
EN = GND
EN = GND, T
J
= −40°C to +125°C
I
OUT
= 10 mA
I
OUT
= 100 μA to 1 A
100 μA < I
OUT
< 1 A, T
J
= −40°C to +125°C
I
OUT
= 10 mA
I
OUT
= 100 μA to 1 A
100 μA < I
OUT
< 1 A, T
J
= −40°C to +125°C
V
IN
= (V
OUT
+ 0.6 V) to 5.5 V,
T
J
= −40°C to +125°C
I
OUT
= 10 mA to 1 A, T
J
= −40°C to +125°C
I
OUT
= 100 mA, V
OUT
≥ 3.3 V
I
OUT
= 100 mA, V
OUT
≥ 3.3 V,
T
J
= −40°C to +125°C
I
OUT
= 1 A, V
OUT
≥ 3.3 V
I
OUT
= 1 A, V
OUT
≥ 3.3 V, T
J
= −40°C to +125°C
I
OUT
= 100 mA, 2.5 V ≤ V
OUT
< 3.3 V
I
OUT
= 100 mA, 2.5 V ≤ V
OUT
< 3.3 V,
T
J
= −40°C to +125°C
I
OUT
= 1 A, 2.5 V ≤ V
OUT
< 3.3 V
I
OUT
= 1 A, 2.5 V ≤ V
OUT
< 3.3 V,
T
J
= −40°C to +125°C
Min
2.5
Typ
50
310
390
1.2
1.55
0.1
1.0
−1
−1.5
−2.5
0.792
0.788
0.780
−0.1
+1
+1.5
+2.5
0.808
0.812
0.820
+0.1
0.001
33
55
345
600
35
60
365
630
Max
5.5
Unit
V
μA
μA
μA
mA
mA
μA
μA
%
%
%
V
V
V
%/ V
%/mA
mV
mV
mV
mV
mV
mV
mV
mV
SHUTDOWN CURRENT
OUTPUT VOLTAGE ACCURACY
Fixed Output Voltage Accuracy
(ADP1706 and ADP1707)
Adjustable Output Voltage Accuracy
(ADP1708)
1
LINE REGULATION
LOAD REGULATION
2
DROPOUT VOLTAGE
3
I
GND-SD
V
OUT
V
OUT
0.8
∆V
OUT
/∆V
IN
∆V
OUT
/∆I
OUT
V
DROPOUT
START-UP TIME
4
ADP1707 and ADP1708
ADP1706
CURRENT LIMIT THRESHOLD
5
THERMAL SHUTDOWN
Thermal Shutdown Threshold
Thermal Shutdown Hysteresis
SOFT START SOURCE CURRENT (ADP1706)
V
OUT
to V
TRK
ACCURACY (ADP1707)
t
START-UP
C
SS
= 10 nF
I
LIMIT
TS
SD
TS
SD-HYS
SS
I-SOURCE
V
TRK-ERROR
T
J
rising
SS = GND
0 V ≤ V
TRK
≤ (0.5 × V
OUT (NOM)
), V
OUT (NOM)
≤ 1.8 V,
T
J
= −40°C to +125°C
0 V ≤ V
TRK
≤ (0.5 × V
OUT (NOM)
), V
OUT (NOM)
> 1.8 V,
T
J
= −40°C to +125°C
2.5 V ≤ V
IN
≤ 5.5 V
2.5 V ≤ V
IN
≤ 5.5 V
EN = IN or GND
0.6
−40
−60
1.1
100
7.3
1.5
150
15
1.1
1.6
+40
+60
μs
ms
A
°C
°C
μA
mV
mV
1.8
EN INPUT
EN Input Logic High
EN Input Logic Low
EN Input Leakage Current
ADJ INPUT BIAS CURRENT (ADP1708)
SENSE INPUT BIAS CURRENT
V
IH
V
IL
V
I-LEAKAGE
ADJ
I-BIAS
SNS
I-BIAS
1.8
0.1
30
4
0.4
1
100
V
V
μA
nA
μA
Rev. 0 | Page 3 of 20
ADP1706/ADP1707/ADP1708
Parameter
OUTPUT NOISE
POWER SUPPLY REJECTION RATIO
Symbol
OUT
NOISE
PSRR
Test Conditions
10 Hz to 100 kHz, V
OUT
= 0.75 V
10 Hz to 100 kHz, V
OUT
= 3.3 V
1 kHz, V
OUT
= 0.75 V
1 kHz, V
OUT
= 3.3 V
Min
Typ
125
450
70
56
Max
Unit
μV rms
μV rms
dB
dB
1
Accuracy when OUT is connected directly to ADJ. When OUT voltage is set by external feedback resistors, absolute accuracy in adjust mode depends on the tolerances
of resistors used.
2
Based on an end-point calculation using 10 mA and 1 A loads. See Figure 11 for typical load regulation performance for loads less than 10 mA.
3
Dropout voltage is defined as the input-to-output voltage differential when the input voltage is set to the nominal output voltage. This applies only for output
voltages above 2.5 V.
4
Start-up time is defined as the time between the rising edge of EN to OUT being at 95% of its nominal value.
5
Current limit threshold is defined as the current at which the output voltage drops to 90% of the specified typical value. For example, the current limit for a 1.0 V
output voltage is defined as the current that causes the output voltage to drop to 90% of 1.0 V, or 0.9 V.
Rev. 0 | Page 4 of 20
ADP1706/ADP1707/ADP1708
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter
IN to GND
OUT to GND
EN to GND
SS/ADJ/TRK to GND
SENSE to GND
Storage Temperature Range
Operating Junction Temperature Range
Soldering Conditions
Rating
−0.3 V to +6 V
–0.3 V to IN
–0.3 V to +6 V
–0.3 V to +6 V
–0.3 V to +6 V
–65°C to +150°C
–40°C to +125°C
JEDEC J-STD-020
THERMAL RESISTANCE
θ
JA
is specified for the worst-case conditions, that is, a device
soldered in a circuit board for surface-mount packages.
Table 3. Thermal Resistance
Package Type
8-Lead SOIC (Exposed Paddle)
8-Lead 3 mm × 3 mm LFCSP (Exposed Paddle)
θ
JA
58
66
Unit
°C/W
°C/W
ESD CAUTION
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.
Rev. 0 | Page 5 of 20
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