ANALOG DEVICES ADP1720 Service Manual
50 mA, High Voltage,
V
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FEATURES
Wide input voltage range: 4 V to 28 V
Maximum output current: 50 mA
Low light load current:
28 μA at 0 μA load
35 μA at 100 μA load
Low shutdown current: 0.7 μA
Low dropout voltage: 275 mV @ 50 mA load
Initial accuracy: ±0.5%
Accuracy over line, load, and temperature: ±2%
Stable with small 1μF ceramic output capacitor
Fixed 3.3 V and 5.0 V output voltage options
Adjustable output voltage option: 1.225 V to 5.0 V
Current limit and thermal overload protection
Logic controlled enable
Space-saving thermally enhanced MSOP package
APPLICATIONS
DC-to-DC post regulation
PCMCIA regulation
Keep-alive power in portable equipment
Industrial applications
Micropower Linear Regulator
ADP1720
TYPICAL APPLICATION CIRCUITS
ADP1720
FIXED
1 8
VIN = 28V
1µF
= 5V
OUT
Figure 1. ADP1720 with Fixed Output Voltage, 5.0 V
1.225V(1 + R1/R2)
Figure 2. ADP1720 with Adjustable Output Voltage, 1.225 V to 5.0 V
VIN = 12V
V
OUT
1µF
1µF
=
2
3
4
R2
R1
1µF
GND
IN
OUT
EN
ADP1720
ADJUSTABLE
1
ADJ
2
IN
3
OUT
4
EN
GND
GND
GND
GND
GND
GND
GND
GND
7
6
5
06111-001
8
7
6
5
06111-002
GENERAL DESCRIPTION
The ADP1720 is a high voltage, micropower, low dropout linear
regulator. Operating over a very wide input voltage range of 4 V
to 28 V, the ADP1720 can provide up to 50 mA of output current.
With just 28 μA of quiescent supply current and a micropower
shutdown mode, this device is ideal for applications that require
low quiescent current.
The ADP1720 is available in fixed output voltages of 3.3 V and
5.0 V. An adjustable version is also available, which allows the
output to be set anywhere between 1.225 V and 5.0 V. An enable
function that allows external circuits to turn on and turn off the
ADP1720 output is available. For automatic startup, the enable
(EN) pin can be connected directly to the input rail.
The ADP1720 is optimized for stable operation with small 1 μF
ceramic output capacitors, allowing for good transient performance while occupying minimal board space.
The ADP1720 operates from –40°C to +125°C and uses current
limit protection and thermal overload protection circuits to
prevent damage to the device in adverse conditions.
Available in a small thermally enhanced MSOP package, the
ADP1720 provides a compact solution with low thermal resistance.
Rev. A
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.
ADP1720
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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
REVISION HISTORY
7/07—Rev. 0 to Rev. A
Change to Figure 1 ........................................................................... 1
Changes to Table 1 ............................................................................ 3
Changes to Ordering Guide .......................................................... 15
2/07—Revision 0: Initial Version
Typical Performance Characteristics ..............................................7
Theory of Operation ...................................................................... 10
Adjustable Output Voltage (ADP1720 Adjustable) ............... 10
Applications Information .............................................................. 11
Capacitor Selection .................................................................... 11
Current Limit and Thermal Overload Protection ................. 11
Thermal Considerations ............................................................ 12
Printed Circuit Board Layout Considerations ....................... 14
Outline Dimensions ....................................................................... 15
Ordering Guide .......................................................................... 15
Rev. A | Page 2 of 16
ADP1720
V
V
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SPECIFICATIONS
VIN = 12 V, I
Table 1.
Parameter Symbol Conditions Min Typ Max Unit
INPUT VOLTAGE RANGE VIN T
OPERATING SUPPLY CURRENT I
I
I
I
I
SHUTDOWN CURRENT I
EN = GND, TJ = –40°C to +125°C 1.5 μA
OUTPUT
Fixed Output V
Voltage Accuracy 100 μA < I
100 μA < I
Adjustable Output
Voltage Accuracy 100 μA < I
100 μA < I
Noise (10 Hz to 100 kHz)
REGULATION
Line Regulation ∆V
Load Regulation
1 mA < I
DROPOUT VOLTAGE
I
I
I
START-UP TIME
CURRENT LIMIT THRESHOLD
THERMAL CHARACTERISTICS
Thermal Shutdown
Threshold
Thermal Shutdown
Hysteresis
EN CHARACTERISTICS
EN Input
Logic High VIH 4 V ≤ VIN ≤ 28 V 1.8 V
Logic Low VIL 4 V ≤ VIN ≤ 28 V 0.4 V
Leakage Current V
EN = IN 0.5 1 μA
ADJ INPUT BIAS CURRENT
(ADP1720 ADJUSTABLE)
= 100 μA, CIN = C
OUT
1
V
2
3
V
4
T
5
I
= 1 μF, TA = 25°C, unless otherwise noted.
OUT
= –40°C to +125°C 4 28 V
J
I
GND
EN = GND 0.7 μA
GND-SD
I
OUT
I
OUT
NOISE
OUT
/∆VIN VIN = (V
OUT
∆V
/∆I
OUT
OUT
I
DROPOUT
200 μs
START-UP
55 90 140 mA
LIMIT
T
TS
SD
15
TS
SD-HYS
EN = GND 0.1 1 μA
I-LEAKAGE
ADJ
30 100 nA
I-BIAS
= 0 μA 28 μA
OUT
= 0 μA,
OUT
greater), T
= 100 μA 35 μA
OUT
= 100 μA, VIN = V
I
OUT
greater), T
= 1 mA 74 μA
OUT
= 1 mA, VIN = V
I
OUT
greater), T
= 10 mA 300 μA
OUT
= 10 mA, VIN = V
I
OUT
greater), T
100 μA < I
(whichever is greater), T
= 100 μA –0.5 +0.5 %
OUT
= 100 μA 1.2188 1.2250 1.2311 V
OUT
V
= 1.6 V, C
OUT
V
= 1.6 V, C
OUT
= 5 V, C
V
OUT
= 5 V, C
V
OUT
1 mA < I
= 10 mA 55 mV
OUT
= 10 mA, TJ = –40°C to +125°C 105 mV
OUT
= 50 mA 275 mV
OUT
= 50 mA, TJ = –40°C to +125°C 480 mV
OUT
rising 150
J
=
IN
= –40°C to +125°C
J
= –40°C to +125°C
J
= –40°C to +125°C
J
= –40°C to +125°C
J
< 50 mA, VIN = V
OUT
< 50 mA –1 +1 %
OUT
< 50 mA, TJ = –40°C to +125°C –2 +2 %
OUT
< 50 mA 1.2127 1.2372 V
OUT
< 50 mA, TJ = –40°C to +125°C 1.2005 1.2495 V
OUT
OUT
OUT
+ 0.5 V) to 28 V, TJ = –40°C to +125°C –0.02 +0.02 %/ V
OUT
< 50 mA 0.001 %/mA
OUT
< 50 mA, TJ = –40°C to +125°C 0.005 %/mA
OUT
+ 0.5 Vor 4V(whichever is
OUT
+ 0.5 V or 4 V (whichever is
OUT
+ 0.5 V or 4 V (whichever is
OUT
+ 0.5 V or 4 V (whichever is
OUT
+ 0.5 V or 4 V
OUT
= –40°C to +125°C
J
= 1 μF 146 μV rms
OUT
= 10 μF 124 μV rms
OUT
= 1 μF
= 10 μF
Rev. A | Page 3 of 16
80 μA
120 μA
340 μA
900 μA
1185 2115 μA
340 μV rms
266 μV rms
°C
°C
ADP1720
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Parameter Symbol Conditions Min Typ Max Unit
POWER SUPPLY REJECTION RATIO PSRR f = 120 Hz, VIN = 8 V, V
f = 1 kHz, VIN = 8 V, V
f = 10 kHz, VIN = 8 V, V
f = 120 Hz, VIN = 8 V, V
f = 1 kHz, VIN = 8 V, V
f = 10 kHz, VIN = 8 V, V
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 1 mA and 50 mA loads. See Fi for typical load regulation performance for loads less than 1 mA. gure 6
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 4 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 5.0 V
output voltage is defined as the current that causes the output voltage to drop to 90% of 5.0 V, or 4.5 V.
= 1.6 V –90 dB
OUT
= 1.6 V –80 dB
OUT
= 1.6 V –60 dB
OUT
= 5 V –83 dB
OUT
= 5 V –70 dB
OUT
= 5 V –50 dB
OUT
Rev. A | Page 4 of 16
ADP1720
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ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter Rating
IN to GND –0.3 V to +30 V
OUT to GND
EN to GND –0.3 V to +30 V
ADJ to GND –0.3 V to +6 V
Storage Temperature Range –65°C to +150°C
Operating Junction
Temperature Range
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.
–0.3 V to IN or +6 V
(whichever is less)
–40°C to +125°C
THERMAL RESISTANCE
θJA 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 θJA θ
8-Lead MSOP 118 57 °C/W
Unit
JC
ESD CAUTION
Rev. A | Page 5 of 16
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