Precision CMOS Amplifier
AD8655/AD8656
Rev. E Document Feedback
rights of third parties that may result from its use. Specifications subject to change without notice. No
Trademarks and registered trademarks are the prop erty of their respective owner s.
Technical Support www.analog.com
Figure 2. AD8656
NC
1
–IN
2
+IN
3
V–
4
NC
8
V+
7
OUT
6
NC
5
AD8655
TOP VIEW
(Not to Scale)
05304-048
NC = NO CONNECT
OUT A
1
–IN A
2
+IN A
3
V–
4
V+
8
OUT B
7
–IN B
6
+IN B
5
AD8656
TOP VIEW
(Not to Scale)
05304-059
Data Sheet
FEATURES
Low noise: 2.7 nV/√Hz at f = 10 kHz
Low offset voltage: 250 µV max over VCM
Offset voltage drift: 0.4 µV/°C typ and 2.3 µV/°C max
Bandwidth: 28 MHz
Rail-to-rail input/output
Unity gain stable
2.7 V to 5.5 V operation
−40°C to +125°C operation
Qualified for automotive applications
APPLICATIONS
ADC and DAC buffers
Audio
Industrial controls
Precision filters
Digital scales
Automotive collision avoidance
PLL filters
Figure 1. AD8655
8-Lead MSOP (RM-8)
8-Lead SOIC (R-8)
Low Noise,
PIN CONFIGURATIONS
8-Lead MSOP (RM-8)
8-Lead SOIC (R-8)
GENERAL DESCRIPTION
The AD8655/AD8656 are the industry’s lowest noise, precision
CMOS amplifiers. They leverage the Analog Devices DigiTrim®
technology to achieve high dc accuracy.
The AD8655/AD8656 provide low noise (2.7 nV/√Hz at 10 kHz),
low THD + N (0.0007%), and high precision performance
(250 µV max over V
to swing rail-to-rail at the input and output enables designers
to buffer analog-to-digital converters (ADCs) and other wide
dynamic range devices in single-supply systems.
) to low voltage applications. The ability
CM
The high precision performance of the AD8655/AD8656 improves
the resolution and dynamic range in low voltage applications.
Audio applications, such as microphone pre-amps and audio
mixing consoles, benefit from the low noise, low distortion, and
high output current capability of the AD8655/AD8656 to reduce
system level noise performance and maintain audio fidelity. The
high precision and rail-to-rail input and output of the AD8655/
AD8656 benefit data acquisition, process controls, and PLL
filter applications.
The AD8655/AD8656 are fully specified over the −40°C to
+125°C temperature range. The AD8655/AD8656 are available
in Pb-free, 8-lead MSOP and SOIC packages. The AD8655/
AD8656 are both available for automotive applications.
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
license is granted by implication or otherwise under any patent or patent rights of Analo g Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700 ©2005–2013 Analog Devices, Inc. All rights reserved.
AD8655/AD8656 Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
Pin Configurations ........................................................................... 1
General Description ......................................................................... 1
Revision History ............................................................................... 2
Specifications ..................................................................................... 3
Absolute Maximum Ratings ............................................................ 5
ESD Caution .................................................................................. 5
Typical Performance Characteristics ............................................. 6
Theory of Operation ...................................................................... 15
Applications Information .............................................................. 16
REVISION HISTORY
10/13—Re v. D t o R e v. E
Changes to Figure 1 Caption and Figure 2 Caption .................... 1
Deleted Figure 3 and Figure 4; Renumbered Sequentially ......... 1
Change to General Description Section ........................................ 1
Change to Figure 4 ........................................................................... 6
Change to Figure 32 ....................................................................... 10
Changes to Ordering Guide .......................................................... 19
Changes to Automotive Products Section ................................... 19
6/13—Re v. C t o R e v. D
Change to Figure 57 ....................................................................... 16
5/13—Re v. B t o R e v. C
Change to Figure 57 ....................................................................... 16
9/11—Re v. A t o R e v. B
Changes to Features Section............................................................ 1
Updated Outline Dimensions ....................................................... 19
Changes to Ordering Guide .......................................................... 19
Added Automotive Products Section .......................................... 19
Input Overvoltage Protection ................................................... 16
Input Capacitance ...................................................................... 16
Driving Capacitive Loads .......................................................... 16
Layout, Grounding, and Bypassing Considerations .................. 18
Power Supply Bypassing ............................................................ 18
Grounding ................................................................................... 18
Leakage Currents ........................................................................ 18
Outline Dimensions ....................................................................... 19
Ordering Guide ............................................................................... 19
Automotive Products ................................................................. 19
6/05—Re v. 0 t o R e v. A
Added AD8656 ................................................................... Universal
Added Figure 2 and Figure 4 ........................................................... 1
Changes to Specifications ................................................................. 3
Changed Caption of Figure 12 and Added Figure 13 ................... 7
Replaced Figure 16 ............................................................................ 7
Changed Caption of Figure 37 and Added Figure 38 ................ 11
Replaced Figure 47 ......................................................................... 13
Added Figure 55 ............................................................................. 14
Changes to Ordering Guide .......................................................... 18
4/05—Revision 0: Initial Version
Rev. E | Page 2 of 20
Data Sheet AD8655/AD8656
Offset Voltage
VOS
VCM = 0 V to 5 V
50
250
µV
Input Offset Current
IOS 10
pA
Output Current
I
V
= ±0.5 V
±220
mA
Power Supply Rejection Ratio
PSRR
VS = 2.7 V to 5.0 V
88
105 dB
INPUT CAPACITANCE
CIN
NOISE PERFORMANCE
Settling Time
ts
To 0.1%, VIN = 0 V to 2 V step, G = +1
370 ns
SPECIFICATIONS
VS = 5.0 V, VCM = VS/2, TA = 25°C, unless otherwise specified.
Table 1.
Parameter Symbol Conditions Min Typ Max Unit
INPUT CHARACTERISTICS
−40°C ≤ TA ≤ +125°C 550 µV
Offset Voltage Drift ΔVOS/ΔT −40°C ≤ TA ≤ +125°C 0.4 2.3 µV/°C
Input Bias Current IB 1 10 pA
−40°C ≤ TA ≤ +125°C 500 pA
−40°C ≤ TA≤ +125°C 500 pA
Input Voltage Range 0 5 V
Common-Mode Rejection Ratio CMRR VCM = 0 V to 5 V 85 100 dB
Large Signal Voltage Gain AVO VO = 0.2 V to 4.8 V, RL = 10 kΩ, VCM = 0 V 100 110 dB
−40°C ≤ TA ≤ +125°C 95 dB
OUTPUT CHARACTERISTICS
Output Voltage High VOH IL = 1 mA; −40°C ≤ TA ≤ +125°C 4.97 4.991 V
Output Voltage Low VOL IL = 1 mA; −40°C ≤ TA ≤ +125°C 8 30 mV
OUT
POWER SUPPLY
OUT
Supply Current/Amplifier ISY VO = 0 V 3.7 4.5 mA
−40°C ≤ TA ≤ +125°C 5.3 mA
Differential 9.3 pF
Common-Mode 16.7 pF
Input Voltage Noise Density en f = 1 kHz 4
f = 10 kHz 2.7
Total Harmonic Distortion + Noise THD + N G = 1, RL = 1 kΩ, f = 1 kHz, VIN = 2 V p-p 0.0007 %
FREQUENCY RESPONSE
Gain Bandwidth Product GBP 28 MHz
Slew Rate SR RL = 10 kΩ 11 V/µs
Phase Margin CL = 0 pF 69 degrees
nV/√Hz
nV/√Hz
Rev. E | Page 3 of 20
AD8655/AD8656 Data Sheet
Offset Voltage Drift
ΔVOS/ΔT
−40°C ≤ TA ≤ +125°C
0.4
2.0
µV/°C
FREQUENCY RESPONSE
VS = 2.7 V, VCM = VS/2, TA = 25°C, unless otherwise specified.
Table 2.
Parameter Symbol Conditions Min Typ Max Unit
INPUT CHARACTERISTICS
Offset Voltage VOS VCM = 0 V to 2.7 V 44 250 µV
−40°C ≤ TA ≤ +125°C 550 µV
Input Bias Current IB 1 10 pA
−40°C ≤ TA ≤ +125°C 500 pA
Input Offset Current IOS 10 pA
−40°C ≤ TA ≤ +125°C 500 pA
Input Voltage Range 0 2.7 V
Common-Mode Rejection Ratio CMRR VCM = 0 V to 2.7 V 80 98 dB
Large Signal Voltage Gain AVO VO = 0.2 V to 2.5 V, RL = 10 kΩ, VCM = 0 V 98 dB
−40°C ≤ TA ≤ +125°C 90 dB
OUTPUT CHARACTERISTICS
Output Voltage High VOH IL = 1 mA; −40°C ≤ TA ≤ +125°C 2.67 2.688 V
Output Voltage Low VOL IL = 1 mA; −40°C ≤ TA ≤ +125°C 10 30 mV
Output Current I
POWER SUPPLY
Power Supply Rejection Ratio PSRR VS = 2.7 V to 5.0 V 88 105 dB
Supply Current/Amplifier ISY VO = 0 V 3.7 4.5 mA
−40°C ≤ TA ≤ +125°C 5.3 mA
INPUT CAPACITANCE CIN
Differential 9.3 pF
Common-Mode 16.7 pF
NOISE PERFORMANCE
Input Voltage Noise Density en f = 1 kHz 4.0
f = 10 kHz 2.7
Total Harmonic Distortion + Noise THD + N G = 1, RL = 1kΩ, f = 1 kHz, VIN = 2 V p-p 0.0007 %
V
OUT
= ±0.5 V ±75 mA
OUT
nV/√Hz
nV/√Hz
Gain Bandwidth Product GBP 27 MHz
Slew Rate SR RL = 10 kΩ 8.5 V/µs
Settling Time ts To 0.1%, VIN = 0 to 1 V step, G = +1 370 ns
Phase Margin CL = 0 pF 54 degrees
Rev. E | Page 4 of 20
Data Sheet AD8655/AD8656
8-Lead SOIC (R)
158
43
°C/W
ABSOLUTE MAXIMUM RATINGS
Table 3.
Parameter Rating
Supply Voltage 6 V
Input Voltage VSS − 0.3 V to VDD + 0.3 V
Differential Input Voltage ±6 V
Output Short-Circuit Duration
to GND
Electrostatic Discharge (HBM) 3.0 kV
Storage Temperature Range
R, RM Packages
Junction Temperature Range
R, RM Packages
Lead Temperature
(Soldering, 10 sec)
Indefinite
−65°C to +150°C
−65°C to +150°C
260°C
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.
Table 4.
Package Type θ
8-Lead MSOP (RM) 210 45 °C/W
1
θJA is specified for worst-case conditions; that is, θJA is specified for a device
soldered in the circuit board for surface-mount packages.
1
θJC Unit
JA
ESD CAUTION
Rev. E | Page 5 of 20
AD8655/AD8656 Data Sheet
60
50
40
30
20
10
0
–
150 –100
–50
0 50
100
150
V
OS
(µV)
NUMBER OF AMPLIFIERS
05304-001
V
S
= ±2.5V
TEMPERATURE (°C)
V
OS
(µV)
06304-004
250
0
–100
–250
–50 0
–25
25 50 75 100 125 150
–200
–150
–50
50
100
150
200
VS = ±2.5V
V
CM
= 0V
–3σ
TYPICAL
+3σ
60
50
40
30
20
10
0
0 0.2 0.4 0.6 0.8
1.0 1.2
|TCVOS| (µV/°C)
1.4 1.6
NUMBER OF AMPLIFIERS
05304-003
V
S
= ±2.5V
20
10
0
–
10
–
20
–
30
0 1 2
3 4
COMMON-MODE VOLTAGE (V)
5 6
V
OS
(µV)
05304-004
V
S
= ±
2.5V
250
200
150
100
50
0
0
20 40 60 80 100
120 140
TEMPERATURE (°
C)
IB (pA)
V
S
= ±2.5V
05304-005
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
0 1 2 3 4
SUPPLY VOLTAGE (V)
5 6
SUPPLY CURRENT (mA)
05304-006
VS =
±2.5V
TYPICAL PERFORMANCE CHARACTERISTICS
Figure 3. Input Offset Voltage Distribution
Figure 4. Input Offset Voltage vs. Temperature
Figure 6. Input Offset Voltage vs. Common-Mode Voltage
Figure 7. Input Bias Current vs. Temperature
Figure 5. |TCVOS | Distribution
Figure 8. Supply Current vs. Supply Voltage
Rev. E | Page 6 of 20
Loading...