Low Noise,
Precision CMOS Amplifier
Data Sheet
AD8655/AD8656
Rev. E Document Feedback
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FEATURES
Low noise: 2.7 nV/Hz at f = 10 kHz
Low offset voltage: 250 µV max over V
CM
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
PIN CONFIGURATIONS
Figure 1. AD8655
8-Lead MSOP (RM-8)
8-Lead SOIC (R-8)
Figure 2. AD8656
8-Lead MSOP (RM-8)
8-Lead SOIC (R-8)
GENERAL DESCRIPTION
The AD8655/AD8656 are the industrys 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
CM
) to low voltage applications. The ability
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.
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.
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
AD8655/AD8656 Data Sheet
Rev. E | Page 2 of 20
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
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
REVISION HISTORY
10/13—Re v. D to Rev. 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 to Re v. D
Change to Figure 57 ....................................................................... 16
5/13—Re v. B to Re v. C
Change to Figure 57 ....................................................................... 16
9/11—Re v. A to Re v. B
Changes to Features Section............................................................ 1
Updated Outline Dimensions ....................................................... 19
Changes to Ordering Guide .......................................................... 19
Added Automotive Products Section .......................................... 19
6/05—Re v. 0 to 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
Data Sheet AD8655/AD8656
Rev. E | Page 3 of 20
SPECIFICATIONS
V
S
= 5.0 V, V
CM
= V
S
/2, T
A
= 25°C, unless otherwise specified.
Table 1.
Parameter Symbol Conditions Min Typ Max Unit
INPUT CHARACTERISTICS
Offset Voltage
V
OS
V
CM
= 0 V to 5 V
50
250
µV
−40°C ≤ T
A
≤ +125°C 550 µV
Offset Voltage Drift ΔV
OS
/ΔT −40°C ≤ T
A
≤ +125°C 0.4 2.3 µV/°C
Input Bias Current I
B
1 10 pA
−40°C ≤ T
A
≤ +125°C 500 pA
Input Offset Current
I
OS
10
pA
−40°C ≤ T
A
≤ +125°C 500 pA
Input Voltage Range 0 5 V
Common-Mode Rejection Ratio CMRR V
CM
= 0 V to 5 V 85 100 dB
Large Signal Voltage Gain A
VO
V
O
= 0.2 V to 4.8 V, R
L
= 10 kΩ, V
CM
= 0 V 100 110 dB
−40°C ≤ T
A
≤ +125°C 95 dB
OUTPUT CHARACTERISTICS
Output Voltage High V
OH
I
L
= 1 mA; −40°C ≤ T
A
≤ +125°C 4.97 4.991 V
Output Voltage Low V
OL
I
L
= 1 mA; −40°C ≤ T
A
≤ +125°C 8 30 mV
Output Current
I
OUT
V
OUT
= ±0.5 V
±220
mA
POWER SUPPLY
Power Supply Rejection Ratio
PSRR
V
S
= 2.7 V to 5.0 V
88
105
dB
Supply Current/Amplifier I
SY
V
O
= 0 V 3.7 4.5 mA
−40°C ≤ T
A
≤ +125°C 5.3 mA
INPUT CAPACITANCE
C
IN
Differential 9.3 pF
Common-Mode 16.7 pF
NOISE PERFORMANCE
Input Voltage Noise Density e
n
f = 1 kHz 4
nV/Hz
f = 10 kHz 2.7
nV/Hz
Total Harmonic Distortion + Noise THD + N G = 1, R
L
= 1 kΩ, f = 1 kHz, V
IN
= 2 V p-p 0.0007 %
FREQUENCY RESPONSE
Gain Bandwidth Product GBP 28 MHz
Slew Rate SR R
L
= 10 kΩ 11 V/µs
Settling Time
ts
To 0.1%, V
IN
= 0 V to 2 V step, G = +1
370
ns
Phase Margin C
L
= 0 pF 69 degrees

AD8656ARZ-REEL7

Mfr. #:
Manufacturer:
Analog Devices Inc.
Description:
Precision Amplifiers Low Noise Prec CMOS Dual
Lifecycle:
New from this manufacturer.
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