ANALOG DEVICES AD8506 Service Manual
20 μA Maximum, Rail-to-Rail I/O,
www.BDTIC.com/ADI
Zero Input Crossover Distortion Amplifiers
FEATURES
PSRR: 100 dB minimum
CMRR: 105 dB typical
Very low supply current: 20 μA per amp maximum
1.8 V to 5.5 V single-supply operation
Rail-to-rail input and output
Low noise
2.8 μV p-p from 0.1 Hz to 10 Hz
45 nV/√Hz @ 1 kHz
2.5 mV offset voltage maximum
Very low input bias current: 1 pA typical
APPLICATIONS
Pressure and position sensors
Remote security
Bio sensors
IR thermometers
Battery-powered consumer equipment
Hazard detectors
GENERAL DESCRIPTION
The AD8506 is a dual micropower amplifier featuring rail-torail input and output swings while operating from a 1.8 V to 5.5 V
single power supply.
Using a novel circuit technology, these low cost amplifiers offer
ero crossover distortion (excellent PSRR and CMRR perform-
z
ance) and very low bias current, while operating with a supply
current of less than 20 μA per amplifier. This amplifier offers
the lowest noise in its power class.
This combination of features makes the AD8506 amplifier an
deal choice for battery-powered applications because it mini-
i
mizes errors due to power supply voltage variations over the
AD8506
PIN CONFIGURATION
1
OUT A
–IN A
+IN A
Figure 1. 8-Lead MSOP (RM Suffix)
V–
AD8506
2
TOP VIEW
3
(Not to Scale)
4
lifetime of the battery and maintains high CMRR even for a
il-to-rail input op amp.
ra
Remote battery-powered sensors, handheld instrumentation
a
nd consumer equipment, hazard detection (for example, smoke,
fire, and gas), and patient monitors can benefit from the features
of the AD8506 amplifier.
The AD8506 is specified for both the industrial temperature
r
ange of −40°C to +85°C and the extended industrial temperature
range of −40°C to +125°C. AD8506 dual amplifiers are available
in 8-lead MSOP packages.
8
7
6
5
V+
OUT B
–IN B
+IN B
06900-002
Rev. 0
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Anal og Devices for its use, nor for any infringements of patents or ot her
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.
AD8506
www.BDTIC.com/ADI
TABLE OF CONTENTS
Features.............................................................................................. 1
Applications....................................................................................... 1
Pin Configuration............................................................................. 1
General Description ......................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Electrical Characteristics ............................................................. 3
REVISION HISTORY
11/07—Revision 0: Initial Version
Absolute Maximum Ratings ............................................................5
Thermal Resistance.......................................................................5
ESD Caution...................................................................................5
Typical Performance Characteristics ..............................................6
Outline Dimensions....................................................................... 12
Ordering Guide .......................................................................... 12
Rev. 0 | Page 2 of 12
AD8506
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SPECIFICATIONS
ELECTRICAL CHARACTERISTICS
VSY = 5 V, VCM = VSY/2, TA = 25°C, RL = 100 kΩ to GND, unless otherwise noted.
Table 1.
Parameter Symbol Conditions Min Typ Max Unit
INPUT CHARACTERISTICS
Offset Voltage VOS 0 V < VCM < 5 V 0.5 2.5 mV
−40°C < TA < +125°C 3 mV
Input Bias Current IB 1 10 pA
−40°C < TA < +85°C 100 pA
−40°C < TA < +125°C 600 pA
Input Offset Current IOS 0.5 5 pA
−40°C < TA < +85°C 50 pA
−40°C < TA < +125°C 130 pA
Input Voltage Range −40°C < TA < +125°C 0 5 V
Common-Mode Rejection Ratio CMRR VCM = 0 V to 5 V 90 105 dB
−40°C < TA < +85°C 90 dB
−40°C < TA < +125°C 85 dB
Large Signal Voltage Gain AVO 0.05 V < V
−40°C < TA < +125°C 100 dB
Offset Voltage Drift
Input Capacitance
OUTPUT CHARACTERISTICS
Output Voltage High VOH R
−40°C < TA < +125°C 4.98 V
R
−40°C < TA < +125°C 4.9 V
Output Voltage Low VOL R
−40°C < TA < +125°C 5 mV
R
−40°C < TA < +125°C 25 mV
Short-Circuit Limit ISC ±55 mA
POWER SUPPLY
Power Supply Rejection Ratio PSRR VS = 1.8 V to 5 V 100 110 dB
−40°C < TA < +85°C 100 dB
−40°C < TA < +125°C 95 dB
Supply Current/Amplifier ISY V
−40°C < TA < +125°C 25 μA
DYNAMIC PERFORMANCE
Slew Rate SR RL = 100 kΩ, CL = 10 pF,
Gain Bandwidth Product GBP 100 kHz
−3 dB Bandwidth 150 kHz
Phase Margin ΦM 60 Degrees
NOISE PERFORMANCE
Peak-to-Peak Noise e
Voltage Noise Density en f = 1 kHz 45 nV/√Hz
Current Noise Density in f = 1 kHz 80 fA/√Hz
/ΔT
ΔV
OS
C
DIFF
CCM
f = 0.1 Hz to 10 Hz 2.8 μV p-p
n p-p
−40°C < T
3 pF
4.2 pF
= 100 kΩ to GND 4.98 4.99 V
L
= 10 kΩ to GND 4.9 4.95 V
L
= 100 kΩ to VS 2 5 mV
L
= 10 kΩ to VS 10 25 mV
L
= VS/2 15 20 μA
O
= +1
A
V
< 4.95 V 105 120 dB
OUT
< +125°C 2 μV/°C
A
13 mV/μs
Rev. 0 | Page 3 of 12
AD8506
www.BDTIC.com/ADI
VSY = 1.8 V, VCM = VSY/2, TA = 25°C, RL = 100 kΩ to GND, unless otherwise noted.
Table 2.
Parameter Symbol Conditions Min Typ Max Unit
INPUT CHARACTERISTICS
Offset Voltage VOS 0 V < VCM < 1.8 V 0.5 2.5 mV
−40°C < TA < +125°C 3 mV
Input Bias Current IB 1 10 pA
−40°C < TA < +85°C 100 pA
−40°C < TA < +125°C 600 pA
Input Offset Current IOS 0.5 5 pA
−40°C < TA < +85°C 50 pA
−40°C < TA < +125°C 100 pA
Input Voltage Range −40°C < TA < +125°C 0 1.8 V
Common-Mode Rejection Ratio CMRR VCM = 0 V to 1.8 V 85 100 dB
−40°C < TA < +85°C 85 dB
−40°C < TA < +125°C 80 dB
Large Signal Voltage Gain AVO 0.05V < V
< 1.75V 95 115 dB
OUT
−40°C < TA < +125°C 95 dB
Offset Voltage Drift
Input Capacitance
ΔV
C
DIFF
CCM
OS
/ΔT
−40°C < T
< +125°C 2.5 μV/°C
A
3 pF
4.2 pF
OUTPUT CHARACTERISTICS
Output Voltage High VOH R
= 100 kΩ to GND 1.78 1.79 V
L
−40°C < TA < +125°C 1.78 V
R
= 10 kΩ to GND 1.65 1.75 V
L
−40°C < TA < +125°C 1.65 V
Output Voltage Low VOL R
= 100 kΩ to VS 2 5 mV
L
−40°C < TA < +125°C 5 mV
R
= 10 kΩ to VS 12 25 mV
L
−40°C < TA < +125°C 25 mV
Short-Circuit Limit ISC ±6.5 mA
POWER SUPPLY
Power Supply Rejection Ratio PSRR VS = 1.8 V to 5 V 100 110 dB
−40°C < TA < +85°C 100 dB
−40°C < TA < +125°C 95 dB
Supply Current/Amplifier ISY V
= VS/2 16.5 20 μA
O
−40°C < TA < +125°C 25 μA
DYNAMIC PERFORMANCE
Slew Rate SR
= 100 kΩ, C
R
L
A
= +1
V
= 10 pF,
L
13 mV/μs
Gain Bandwidth Product GBP 100 kHz
−3 dB Bandwidth 150 kHz
Phase Margin Φ
M
60 Degrees
NOISE PERFORMANCE
Peak-to-Peak Noise e
f = 0.1 Hz to 10 Hz 2.8 μV p-p
n p-p
Voltage Noise Density en f = 1 kHz 45 nV/√Hz
Current Noise Density in f = 1 KHz 80 fA/√Hz
Rev. 0 | Page 4 of 12
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