Analog Devices AD8628 9 30 d Datasheet
O
A
A
Zero-Drift, Single-Supply, Rail-to-Rail
FEATURES
Lowest auto-zero amplifier noise
Low offset voltage: 1 µV
Input offset drift: 0.002 µV/°C
Rail-to-rail input and output swing
5 V single-supply operation
High gain, CMRR, and PSRR: 120 dB
Very low input bias current: 100 pA max
Low supply current: 1.0 mA
Overload recovery time: 10 µs
No external components required
APPLICATIONS
Automotive sensors
Pressure and position sensors
Strain gage amplifiers
Medical instrumentation
Thermocouple amplifiers
Precision current sensing
Photodiode amplifier
Input/Output Operational Amplifier
AD8628/AD8629/AD8630
PIN CONFIGURATIONS
OUT
1
AD8628
TOP VIEW
V–
2
(Not to Scale)
+IN
3
Figure 1. 5-Lead TSOT (UJ-5)
and 5-Lead SOT-23 (RT-5)
NC
1
AD8628
–IN
2
+IN
3
TOP VIEW
(Not to Scale)
V–
4
NC = NO CONNECT
Figure 2. 8-Lead SOIC (R-8)
OUT A
1
V–
AD8629
2
3
TOP VIEW
(Not to Scale)
4
–IN A
+IN A
Figure 3. 8-Lead SOIC (R-8)
V+
5
–IN
4
02735-001
NC
8
V+
7
OUT
6
NC
5
02735-002
V+
8
OUT B
7
–IN B
6
+IN B
5
02735-063
Rev. D
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.
UT
–IN A
+IN A
V–
1
AD8629
2
TOP VIEW
3
(Not to Scale)
4
8
7
6
5
V+
OUT B
–IN B
+IN B
02735-064
Figure 4. 8-Lead MSOP (RM-8)
OUT A
–IN A
+IN A
+IN B
–IN B
OUT B
V+
1
2
3
AD8630
TOP VIEW
4
(Not to Scale)
5
6
7
14
13
12
11
10
9
8
OUT D
–IN D
+IN D
V–
+IN C
–IN C
OUT C
02735-066
Figure 5. 14-Lead SOIC (R-14)
OUT
–IN A
+IN A
+IN B
–IN B
OUT B
V+
1
2
3
AD8630
TOP VIEW
4
(Not to Scale)
5
6
7
14
13
12
11
10
9
8
OUT D
–IN D
+IN D
V–
+IN C
–IN C
OUT C
02735-065
Figure 6. 14-Lead TSSOP (RU-14)
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.326.8703 © 2005 Analog Devices, Inc. All rights reserved.
www.analog.com
AD8628/AD8629/AD8630
TABLE OF CONTENTS
Specifications..................................................................................... 4
Electrical Characteristics – V
Electrical Characteristics – V
Absolute Maximum Ratings............................................................ 6
ESD Caution.................................................................................. 6
Typical Performance Characteristics .............................................7
Functional Description.................................................................. 15
1/f Noise....................................................................................... 15
Peak-to-Peak Noise ....................................................................16
Noise Behavior with First-Order Low-Pass Filter.................. 16
= 5.0 V .............................................4
s
= 2.7 V .............................................5
s
REVISION HISTORY
1/05—Rev. C to Rev. D
Added AD8630....................................................................Universal
Added Figure 5 and Figure 6........................................................... 1
Changes to Caption in Figure 8 and Figure 9............................... 7
Changes to Caption in Figure 14.................................................... 8
Changes to Figure 17........................................................................ 8
Changes to Figure 23 and Figure 24............................................... 9
Changes to Figure 25 and Figure 26............................................. 10
Changes to Figure 31...................................................................... 11
Changes to Figure 40, Figure 41, Figure 42................................. 12
Changes to Figure 43 and Figure 44............................................. 13
Changes to Figure 51...................................................................... 15
Updated Outline Dimensions....................................................... 20
Changes to Ordering Guide.......................................................... 22
Total Integrated Input-Referred Noise
for First-Order Filter.................................................................. 16
Input Overvoltage Protection................................................... 17
Output Phase Reversal............................................................... 17
Overload Recovery Time .......................................................... 17
Infrared Sensors.......................................................................... 18
Precision Current Shunt Sensor............................................... 19
Output Amplifier for High Precision DACs........................... 19
Outline Dimensions....................................................................... 20
Ordering Guide .......................................................................... 22
10/03—Rev. A to Rev. B
Changes to General Description .....................................................1
Changes to Absolute Maximum Ratings........................................4
Changes to Ordering Guide.............................................................4
Added TSOT-23 Package .............................................................. 15
6/03—Rev. 0 to Rev. A
Changes to Specifications.................................................................3
Changes to Ordering Guide.............................................................4
Change to Functional Description............................................... 10
Updated Outline Dimensions....................................................... 15
10/02—Revision 0: Initial Version
10/04—B to Rev. C
Updated Formatting...........................................................Universal
Added AD8629....................................................................Universal
Added SOIC and MSOP Pin Configurations ............................... 1
Added Figure 48.............................................................................. 13
Changes to Figure 62...................................................................... 17
Added MSOP Package................................................................... 19
Changes to Ordering Guide.......................................................... 22
Rev. D | Page 2 of 24
AD8628/AD8629/AD8630
GENERAL DESCRIPTION
This amplifier has ultralow offset, drift, and bias current. The
AD8628/AD8629/AD8630 are wide bandwidth auto-zero
amplifiers featuring rail-to-rail input and output swings and low
noise. Operation is fully specified from 2.7 V to 5 V single
supply (±1.35 V to ±2.5 V dual supply).
The AD8628/AD8629/AD8630 provide benefits previously
found only in expensive auto-zeroing or chopper-stabilized
amplifiers. Using Analog Devices’ topology, these zero-drift
amplifiers combine low cost with high accuracy and low noise.
No external capacitor is required. In addition, the AD8628/
AD8629/AD8630 greatly reduce the digital switching noise
found in most chopper-stabilized amplifiers.
With an offset voltage of only 1 µ V, drift of less than
0.005 µV/°C, and noise of only 0.5 µV p-p (0 Hz to 10 Hz), the
AD8628/ AD8629/AD8630 are perfectly suited for applications
in which error sources cannot be tolerated. Position and
pressure sensors, medical equipment, and strain gage amplifiers
benefit greatly from nearly zero drift over their operating
temperature range. Many systems can take advantage of the railto-rail input and output swings provided by the
AD8628/AD8629/AD8630 to reduce input biasing complexity
and maximize SNR.
The AD8628/AD8629/AD8630 are specified for the extended
industrial temperature range (−40°C to +125°C). The AD8628 is
available in tiny TSOT-23, SOT-23, and the 8-lead narrow SOIC
plastic packages. The AD8629 is available in the standard 8-lead
narrow SOIC and MSOP plastic packages. The AD8630 quad
amplifier is available in standard 14-lead SOIC and TSSOP
plastic packages.
Rev. D | Page 3 of 24
AD8628/AD8629/AD8630
SPECIFICATIONS
ELECTRICAL CHARACTERISTICS – VS = 5.0 V
VS = 5.0 V, VCM = 2.5 V, TA = 25°C, unless otherwise noted.
Table 1.
Parameter Symbol Conditions Min Typ Max Unit
INPUT CHARACTERISTICS
Offset Voltage VOS 1 5 µV
−40°C ≤ TA ≤ +125°C 10 µV
Input Bias Current IB 30 100 pA
(AD8630) 100 300 pA
−40°C ≤ TA ≤ +125°C 1.5 nA
Input Offset Current IOS 50 200 pA
−40°C ≤ TA ≤ +125°C 250 pA
Input Voltage Range 0 5 V
Common-Mode Rejection Ratio CMRR VCM = 0 V to 5 V 120 140 dB
−40°C ≤ TA ≤ +125°C 115 130 dB
Large Signal Voltage Gain1 A
−40°C ≤ TA ≤ +125°C 120 135 dB
Offset Voltage Drift ∆VOS/∆T −40°C ≤ TA ≤ +125°C 0.002 0.02 µV/°C
OUTPUT CHARACTERISTICS
Output Voltage High VOH R
−40°C ≤ TA ≤ +125°C 4.99 4.995 V
R
−40°C ≤ TA ≤ +125°C 4.95 4.97 V
Output Voltage Low VOL R
−40°C ≤ TA ≤ +125°C 2 5 mV
R
−40°C ≤ TA ≤ +125°C 15 20 mV
Short-Circuit Limit ISC ±25 ±50 mA
−40°C ≤ TA ≤ +125°C ±40 mA
Output Current IO ±30 mA
−40°C ≤ TA ≤ +125°C ±15 mA
POWER SUPPLY
Power Supply Rejection Ratio PSRR VS = 2.7 V to 5.5 V
−40°C ≤ TA ≤ +125°C 115 130 dB
Supply Current/Amplifier ISY V
−40°C ≤ TA ≤ +125°C 1.0 1.2 mA
INPUT CAPACITANCE
Differential CIN 1.5 pF
Common-Mode 8.0 pF
DYNAMIC PERFORMANCE
Slew Rate SR RL = 10 kΩ 1.0 V/µs
Overload Recovery Time 0.05 ms
Gain Bandwidth Product GBP 2.5 MHz
NOISE PERFORMANCE
Voltage Noise en p-p 0.1 Hz to 10 Hz 0.5 µV p-p
e
Voltage Noise Density en f = 1 kHz 22 nV/√Hz
Current Noise Density in f = 10 Hz 5 fA/√Hz
1
Gain testing is highly dependent upon test bandwidth.
R
VO
p-p 0.1 Hz to 1.0 Hz 0.16 µV p-p
n
= 10 kΩ, VO = 0.3 V to 4.7 V 125 145 dB
L
= 100 kΩ to ground 4.99 4.996 V
L
= 10 kΩ to ground 4.95 4.98 V
L
= 100 kΩ to V+ 1 5 mV
L
= 10 kΩ to V+ 10 20 mV
L
= 0 V 0.85 1.1 mA
O
Rev. D | Page 4 of 24
AD8628/AD8629/AD8630
ELECTRICAL CHARACTERISTICS – VS = 2.7 V
VS = 2.7 V, VCM = 1.35 V, VO = 1.4 V, TA = 25°C, unless otherwise noted.
Table 2.
Parameter Symbol Conditions Min Typ Max Unit
INPUT CHARACTERISTICS
Offset Voltage VOS 1 5 µV
−40°C ≤ TA ≤ +125°C 10 µV
Input Bias Current IB 30 100 pA
(AD8630) 100 300 pA
−40°C ≤ TA ≤ +125°C 1.0 1.5 nA
Input Offset Current IOS 50 200 pA
−40°C ≤ TA ≤ +125°C 250 pA
Input Voltage Range 0 2.7 V
Common-Mode Rejection Ratio CMRR VCM = 0 V to 2.7 V 115 130 dB
−40°C ≤ TA ≤ +125°C 110 120 dB
Large Signal Voltage Gain AVO R
−40°C ≤ TA ≤ +125°C 105 130 dB
Offset Voltage Drift ∆VOS/∆T −40°C ≤ TA ≤ +125°C 0.002 0.02 µV/°C
OUTPUT CHARACTERISTICS
Output Voltage High VOH R
−40°C ≤ TA ≤ +125°C 2.68 2.695 V
R
−40°C ≤ TA ≤ +125°C 2.67 2.675 V
Output Voltage Low VOL R
−40°C ≤ TA ≤ +125°C 2 5 mV
R
−40°C ≤ TA ≤ +125°C 15 20 mV
Short-Circuit Limit ISC ±10 ±15 mA
−40°C ≤ TA ≤ +125°C ±10 mA
Output Current IO ±10 mA
−40°C ≤ TA ≤ +125°C ±5 mA
POWER SUPPLY
Power Supply Rejection Ratio PSRR VS = 2.7 V to 5.5 V
−40°C ≤ TA ≤ +125°C 115 130 dB
Supply Current/Amplifier ISY V
−40°C ≤ TA ≤ +125°C 0.9 1.2 mA
INPUT CAPACITANCE
Differential CIN 1.5 pF
Common-Mode 8.0 pF
DYNAMIC PERFORMANCE
Slew Rate SR RL = 10 kΩ 1 V/µs
Overload Recovery Time 0.05 ms
Gain Bandwidth Product GBP 2 MHz
NOISE PERFORMANCE
Voltage Noise en p-p 0.1 Hz to 10 Hz 0.5 µV p-p
Voltage Noise Density en f = 1 kHz 22 nV/√Hz
Current Noise Density in f = 10 Hz 5 fA/√Hz
= 10 kΩ , VO = 0.3 V to 2.4 V 110 140 dB
L
= 100 kΩ to ground 2.68 2.695 V
L
= 10 kΩ to ground 2.67 2.68 V
L
= 100 kΩ to V+ 1 5 mV
L
= 10 kΩ to V+ 10 20 mV
L
= 0 V 0.75 1.0 mA
O
Rev. D | Page 5 of 24
AD8628/AD8629/AD8630
ABSOLUTE MAXIMUM RATINGS
Table 3.
Parameters Ratings
Supply Voltage 6 V
Input Voltage GND − 0.3 V to VS− + 0.3 V
Differential Input Voltage1 ±5.0 V
Output Short-Circuit Duration to GND Indefinite
Storage Temperature Range
R, RM,RU, RT, UJ Packages −65°C to +150°C
Operating Temperature Range −40°C to +125°C
Junction Temperature Range
R, RM,RU, RT, UJ Packages −65°C to +150°C
Lead Temperature Range
300°C
(Soldering, 60 sec)
1
Differential input voltage is limited to ±5 V or the supply voltage, whichever
is less.
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. Thermal Characteristics
Package Type θ
5-Lead TSOT-23 (UJ-5) 207 61 °C/W
5-Lead SOT-23 (RT-5) 230 146 °C/W
8-Lead SOIC (R-8) 158 43 °C/W
8-Lead MSOP (RM-8) 190 44 °C/W
14-Lead SOIC (R-14) 105 43 °C/W
14-Lead TSSOP (RU-14) 148 23 °C/W
1
θJA is specified for worst-case conditions, that is, θJA is specified for the device
soldered in a circuit board for surface-mount packages. This was measured
using a standard 2-layer board.
1
θ
JA
Unit
JC
ESD CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on
the human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.
Rev. D | Page 6 of 24
AD8628/AD8629/AD8630
TYPICAL PERFORMANCE CHARACTERISTICS
180
VS = 2.7V
= 25°C
T
160
A
140
120
100
80
60
NUMBER OF AMPLIFIERS
40
20
0
–2.5 –1.5 –0.5 0.5 1.5 2.5
INPUT OFFSET VOLTAGE (µV)
Figure 7. Input Offset Voltage Distribution at 2.7 V
02735-003
100
VS = 5V
90
= 2.5V
V
CM
= 25°C
T
A
80
70
60
50
40
30
NUMBER OF AMPLIFIERS
20
10
0
–2.5 –1.5 –0.5 0.5 1.5 2.5
INPUT OFFSET VOLTAGE (µV)
Figure 10. Input Offset Voltage Distribution at 5 V
02735-006
60
VS = 5V
50
40
30
20
INPUT BIAS CURRENT (pA)
10
0
012345
INPUT COMMON-MODE VOLTAGE (V)
+85°C
+25°C
–40°C
02735-004
6
Figure 8. AD8628 Input Bias Current vs. Input Common-Mode Voltage at 5 V
1500
VS = 5V
1000
500
0
–500
INPUT BIAS CURRENT (pA)
–1000
150°C
125°C
7
VS = 5V
TA = –40°C TO +125°C
6
5
4
3
2
NUMBER OF AMPLIFIERS
1
0
0
2
Figure 11. Input Offset Voltage Drift
1k
VS = 5V
= 25°C
T
A
100
10
1
OUTPUT VOLTAGE (mV)
0.1
4
TCVOS (nV/°C)
SOURCE
68
SINK
10
02735-007
–1500
012345
INPUT COMMON-MODE VOLTAGE (V)
02735-005
6
Figure 9. AD8628 Input Bias Current vs. Input Common-Mode Voltage at 5 V
Rev. D | Page 7 of 24
0.01
0.0001 0.001 0.10.01 1 10
LOAD CURRENT (mA)
Figure 12. Output Voltage to Supply Rail vs. Load Current at 5 V
02735-008
AD8628/AD8629/AD8630
1k
VS = 2.7V
1000
TA = 25°C
100
10
SOURCE
1
OUTPUT VOLTAGE (mV)
0.1
0.01
0.0001 0.001 0.10.01 1 10
LOAD CURRENT (mA)
SINK
Figure 13. Output Voltage to Supply Rail vs. Load Current at 2.7 V
1500
VS = 5V
V
= 2.5V
CM
= –40°C TO +150°C
T
A
1150
900
450
INPUT BIAS CURRENT (pA)
100
02735-009
800
A)
µ
600
400
SUPPLY CURRENT (
200
0
012 4536
SUPPLY VOLTAGE (V)
02735-012
Figure 16. Supply Current vs. Supply Voltage
60
40
20
0
OPEN-LOOP GAIN (dB)
VS = 2.7V
= 20pF
C
L
= ∞
R
L
φ
= 45°
M
0
45
90
135
180
225
PHASE SHIFT (Degrees)
0
–50 0 25–25 50 75 100 125 150 175
TEMPERATURE (°C)
Figure 14. AD8628 Input Bias Current vs. Temperature
1250
TA = 25°C
1000
A)
µ
750
500
SUPPLY CURRENT (
250
0
–50 0 50 150100 200
TEMPERATURE (
°C
5V
2.7V
)
Figure 15. Supply Current vs. Temperature
02735-010
02735-011
10k 100k 1M 10M
FREQUENCY (Hz)
Figure 17. Open-Loop Gain and Phase vs. Frequency
70
60
50
40
30
20
10
0
OPEN-LOOP GAIN (dB)
–10
–20
–30
10k 100k 1M 10M
FREQUENCY (Hz)
Figure 18. Open-Loop Gain and Phase vs. Frequency
VS = 5V
= 20pF
C
L
= ∞
R
L
= 52.1°
φ
M
02735-013
0
45
90
135
180
225
02735-014
PHASE SHIFT (Degrees)
Rev. D | Page 8 of 24
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