Analog Devices AD8675 Service Manual
36 V Precision, 2.8 nV/√Hz
FEATURES
Very low voltage noise: 2.8 nV/√Hz
Rail-to-rail output swing
Low input bias current: 2 nA maximum
Very low offset voltage: 75 μV maximum
Low input offset drift: 0.6 μV/°C maximum
Very high gain: 120 dB
Wide bandwidth: 10 MHz typical
±5 V to ±18 V operation
APPLICATIONS
Precision instrumentation
PLL filters
Laser diode control loops
Strain gage amplifiers
Medical instrumentation
Thermocouple amplifiers
GENERAL DESCRIPTION
The AD8675 precision operational amplifier has ultralow offset,
drift, and voltage noise combined with very low input bias
currents over the full operating temperature range. The AD8675
is a precision, wide bandwidth op amp featuring rail-to-rail
output swings and very low noise. Operation is fully specified
from ±5 V to ±15 V.
The AD8675 features a rail-to-rail output like that of the
but with wide bandwidth and even lower voltage noise, combined with the precision and low power consumption like that
of the industry-standard OP07 amplifier. Unlike other low
noise, rail-to-rail op amps, the AD8675 has very low input bias
current and low input current noise.
With typical offset voltage of only 10 µV, offset drift of 0.2 µV/°C,
and noise of only 0.10 V p-p (0.1 Hz to 10 Hz), the AD8675 is
perfectly suited for applications where large error sources
cannot be tolerated. For applications with even lower offset
tolerances, the proprietary nulling capability allows a combination
of both device and system offset errors up to 3.5 mV (referred
OP184,
Rail-to-Rail Output Op Amp
AD8675
PIN CONFIGURATIONS
1
NULL
–IN
+IN
V–
NULL
–IN
+IN
V–
AD8675
2
3
TOP VIEW
(Not to Scale)
4
NC = NO CONNECT
Figure 1. 8-Lead SOIC_N (R-8)
1
AD8675
2
TOP VIEW
3
(Not to Scale)
4
NC = NO CONNECT
Figure 2. 8-Lead MSOP (RM-8)
to the input) to be compensated externally. Unlike previous
circuits, the AD8675 accommodates this adjustment without
adversely affecting the offset drift, CMRR, and PSRR of the
amplifier. Precision instrumentation, PLL, and other precision
filter circuits, position and pressure sensors, medical instrumentation, and strain gage amplifiers benefit greatly from the very
low noise, low input bias current, and wide bandwidth. Many
systems can take advantage of the low noise, dc precision, and
rail-to-rail output swing provided by the AD8675 to maximize
SNR and dynamic range.
The smaller packages and low power consumption afforded by
the AD8675 allow maximum channel density or minimum
board size for space-critical equipment.
The AD8675 is specified for the extended industrial temperature
range (−40°C to +125°C). The AD8675 amplifier is available in
the tiny 8-lead MSOP, and the popular 8-lead, narrow SOIC,
RoHS compliant packages. MSOP packaged devices are only
available in tape and reel format.
8
7
6
5
8
7
6
5
NULL
V+
OUT
NC
NULL
V+
OUT
NC
05564-001
05564-002
Rev. A
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 ©2005-2007 Analog Devices, Inc. All rights reserved.
AD8675
TABLE OF CONTENTS
Features.............................................................................................. 1
Applications....................................................................................... 1
Pin Configurations ........................................................................... 1
General Description ......................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Electrical Specifications............................................................... 3
REVISION HISTORY
4/07—Rev. 0 to Rev. A
Inserted Figure 7 and Figure 8;
renumbered sequentially ................................................................. 6
10/05—Revision 0: Initial Version
Absolute Maximum Ratings ............................................................5
Thermal Resistance.......................................................................5
ESD Caution...................................................................................5
Typical Performance Characteristics..............................................6
Outline Dimensions....................................................................... 11
Ordering Guide .......................................................................... 11
Rev. A | Page 2 of 12
AD8675
SPECIFICATIONS
ELECTRICAL SPECIFICATIONS
VS = ±5.0 V, VCM = 0 V, VO = 0 V, TA = +25°C, unless otherwise specified.
Table 1.
Parameter Symbol Conditions Min Typ Max Unit
INPUT CHARACTERISTICS
Offset Voltage VOS 10 75 μV
−40°C ≤ TA ≤ +125°C 12 240
Input Bias Current IB −2 0.5 2 nA
−40°C ≤ TA ≤ +125°C −5.5 −2 5.5 nA
Input Offset Current IOS −1 0.1 1 nA
−40°C ≤ TA ≤ +125°C −2.8 0.1 2.8 nA
Input Voltage Range −3.5 3.5 V
Common-Mode Rejection Ratio CMRR VCM = −3.5 V to +3.5 V 105 130 dB
−40°C ≤ TA ≤ +125°C 105 130 dB
Open-Loop Gain AVO R
V
−40°C ≤ TA ≤ +125°C 700 1250 V/mV
Offset Voltage Drift ΔVOS/ΔT −40°C ≤ TA ≤ +125°C 0.2 0.6 μV/°C
OUTPUT CHARACTERISTICS
Output Voltage High VOH R
−40°C ≤ TA ≤ +125°C 4.82 4.85 V
Output Voltage Low VOL R
−40°C ≤ TA ≤ +125°C −4.91 −4.82 V
Short-Circuit Limit ISC 40 mA
Output Current IO ±20 mA
POWER SUPPLY
Power Supply Rejection Ratio PSRR VS = ±5.0 V to ±15.0 V 120 140 dB
−40°C ≤ TA ≤ +125°C 120 140 dB
Supply Current/Amplifier ISY V
−40°C ≤ TA ≤ +125°C 2.7 3.4 mA
DYNAMIC PERFORMANCE
Slew Rate SR RL = 2 kΩ 2.5 V/μs
Gain Bandwidth Product GBP 10 MHz
NOISE PERFORMANCE
Voltage Noise e
0.1 Hz to 10 Hz 0.1 μV p-p
n p-p
Voltage Noise Density en f = 1 kHz 2.8 nV/√Hz
Current Noise Density in f = 10 Hz 0.3 pA/√Hz
= 2 kΩ to ground, 1000 2000 V/mV
L
= −4.0 V to +4.0 V
O
= 2 kΩ to ground 4.86 4.90 V
L
= 2 kΩ to ground −4.91 −4.86 V
L
= 0 V 2.3 2.7 mA
O
Rev. A | Page 3 of 12
AD8675
VS = ±15 V, VCM = 0 V, VO = 0 V, TA = +25°C, unless otherwise specified.
Table 2.
Parameter Symbol Conditions Min Typ Max Units
INPUT CHARACTERISTICS
Offset Voltage VOS 10 75 μV
−40°C ≤ TA ≤ +125°C 12 240
Input Bias Current IB −2 0.5 2 nA
−40°C ≤ TA ≤ +125°C −4.5 1 4.5 nA
Input Offset Current IOS −1 0.1 1 nA
−40°C ≤ TA ≤ +125°C −2.8 0.1 2.8 nA
Input Voltage Range −13.5 13.5 V
Common-Mode Rejection Ratio CMRR VCM = −12.5 V to +12.5 V 114 130 dB
−40°C ≤ TA ≤ +125°C 114 130 dB
Open-Loop Gain AVO R
V
−40°C ≤ TA ≤ +125°C 700 1700 V/mV
Offset Voltage Drift ΔVOS/ΔT −40°C ≤ TA ≤ +125°C 0.2 0.6 μV/°C
OUTPUT CHARACTERISTICS
Output Voltage High VOH SOIC RL: 2 kΩ to ground 14.75 14.8 V
MSOP RL: 2 kΩ to ground 14.67 14.78 V
SOIC −40°C ≤ TA ≤ +125°C 14.69 14.75 V
MSOP −40°C ≤ TA ≤ +125°C 14.3 14.66 V
Output Voltage Low VOL R
−40°C ≤ TA ≤ +125°C −14.78 −14.69 V
Short-Circuit Limit ISC 40 mA
Output Current IO ±20 mA
POWER SUPPLY
Power Supply Rejection Ratio PSRR VS = ±5.0 V to ±15.0 V 120 140 dB
−40°C ≤ TA ≤ +125°C 120 140 dB
Supply Current/Amplifier ISY V
−40°C ≤ TA ≤ +125°C 2.9 3.8 mA
DYNAMIC PERFORMANCE
Slew Rate SR RL =10 kΩ 2.5 V/μs
Gain Bandwidth Product GBP 10 MHz
NOISE PERFORMANCE
Voltage Noise e
0.1 Hz to 10 Hz 0.1 μV p-p
n p-p
Voltage Noise Density en f = 1 kHz 2.8 nV/√Hz
Current Noise Density in f = 10 Hz 0.3 pA/√Hz
= 2 kΩ to ground, 1500 4000 V/mV
L
= −14.0 V to +14.0 V
O
= 2 kΩ to ground −14.85 −14.75 V
L
= 0 V 2.5 2.9 mA
O
Rev. A | Page 4 of 12
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