AD8682ARZ-REEL [ADI]
Dual/Quad Low Power, High Speed JFET Operational Amplifiers; 双/四通道，低功耗，高速JFET运算放大器
| 型号： | AD8682ARZ-REEL |
| 厂家： | 
ADI |
| 描述： | Dual/Quad Low Power, High Speed JFET Operational Amplifiers |
| 文件： | 总16页 (文件大小：273K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Dual/Quad Low Power, High Speed
JFET Operational Amplifiers
AD8682/AD8684
PIN CONFIGURATIONS
FEATURES
Low supply current: 250 μA/amp maximum
High slew rate: 9 V/μs
Bandwidth: 3.5 MHz typical
Low offset voltage: 1 mV maximum @ 25°C
Low input bias current: 20 pA maximum @ 25°C
CMRR: 90 dB typical
OUT A
–IN A
+IN A
V–
1
2
3
4
8
7
6
5
V+
AD8682
OUT B
–IN B
+IN B
TOP VIEW
(Not to Scale)
Figure 1. 8-Lead SOIC_N and 8-Lead MSOP
Fast settling time
14
OUT D
OUT A
–IN A
+IN A
V+
1
2
3
4
5
6
7
Unity gain stable
13 –IN D
12 +IN D
APPLICATIONS
11
V–
AD8684
Portable telecommunication
Low power industrial and instrumentation
Loop filters
10 +IN C
+IN B
–IN B
OUT B
9
8
–IN C
OUT C
Active and precision filters
Integrators
TOP VIEW
(Not to Scale)
Strain gauge amplifiers
Portable medical instrumentation
Supply current monitoring
Figure 2. 14-Lead SOIC_N and 14-Lead TSSOP
GENERAL DESCRIPTION
The devices are ideal for portable, low power applications,
especially with high source impedance. The devices are unity gain
stable and can drive higher capacity loads (G = 1, noninverting),
as an example of their excellent dynamic response over a wide
range of conditions, delivering dc precision performance at low
quiescent currents.
The AD8682 and AD8684 are dual and quad low power, precision
(1 mV) JFET amplifiers featuring excellent speed at low supply
currents. The slew rate is typically 9 V/μs with a supply current
under 250 μA per amplifier. These unity-gain stable amplifiers
have a typical gain bandwidth of 3.5 MHz. The JFET input stage
ensures bias current is typically a few picoamps and below 125 pA
maximum over the full temperature operating range.
Rev. 0
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 registeredtrademarks arethe property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
www.analog.com
©2006 Analog Devices, Inc. All rights reserved.
AD8682/AD8684
TABLE OF CONTENTS
Features .............................................................................................. 1
ESD Caution...................................................................................4
Typical Performance Characteristic................................................5
Applications Information.............................................................. 10
High-Side Signal Conditioning ................................................ 10
Phase Inversion........................................................................... 10
Active Filters ............................................................................... 10
Programmable State Variable Filter ......................................... 11
Outline Dimensions....................................................................... 12
Ordering Guide .......................................................................... 13
Applications....................................................................................... 1
Pin Configurations ........................................................................... 1
General Description......................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Electrical Characteristics............................................................. 3
Absolute Maximum Ratings............................................................ 4
Thermal Resistance ...................................................................... 4
REVISION HISTORY
10/06—Revision 0: Initial Version
Rev. 0 | Page 2 of 16
AD8682/AD8684
SPECIFICATIONS
ELECTRICAL CHARACTERISTICS
VS = 15.0 V, TA = 25°C, VCM = 0 V, unless otherwise noted.
Table 1.
Parameter
Symbol
Conditions
Min
Typ
Max
Unit
INPUT CHARACTERISTICS
Offset Voltage
VOS
0.35
1
mV
mV
mV
mV
mV
pA
pA
pA
pA
V
AD8682: +25°C ≤ TA ≤ +85°C
AD8684: +25°C ≤ TA ≤ +85°C
AD8682: −40°C ≤ TA ≤ +25°C
AD8684: −40°C ≤ TA ≤ +25°C
2.5
3.5
3
4
Input Bias Current
IB
6
20
125
20
100
+15
−40°C ≤ TA ≤ +85°C
−40°C ≤ TA ≤ +85°C
Input Offset Current
IOS
Input Voltage Range
Common-Mode Rejection Ratio
Large Signal Voltage Gain
−11
70
20
CMRR
AVO
−11 V ≤ VCM ≤ +15 V, −40°C ≤ TA ≤ +85°C
RL = 10 kΩ
RL = 10 kΩ, −40°C ≤ TA ≤ +85°C
90
dB
V/mV
V/mV
μV/°C
pA/°C
15
Offset Voltage Drift
Bias Current Drift
ΔVOS/ΔT
ΔIB/ΔT
10
8
OUTPUT CHARACTERISTICS
Output Voltage High
Output Voltage Low
Short-Circuit Limit
VOH
VOL
ISC
RL = 10 kΩ
RL = 10 kΩ
Source
Sink
f = 1 MHz
+13.5
3
+13.9
−13.9
10
−12
200
V
V
mA
mA
Ω
−13.5
−8
Open-Loop Output Impedance
POWER SUPPLY
ZOUT
Power Supply Rejection Ratio
Supply Current/Amplifier
Supply Voltage Range
DYNAMIC PERFORMANCE
Slew Rate
Full-Power Bandwidth
Settling Time
Gain Bandwidth Product
Phase Margin
PSRR
ISY
VS
VS = 4.5 V to 18 V, −40°C ≤ TA ≤ +85°C
VO = 0 V, −40°C ≤ TA ≤ +85°C
92
4.5
7
114
210
dB
μA
V
250
18
SR
BWP
tS
GBP
ØO
RL = 10 kΩ
1% distortion
To 0.01%
9
V/μs
kHz
μs
MHz
Degrees
125
1.6
3.5
55
NOISE PERFORMANCE
Voltage Noise
Voltage Noise Density
Current Noise Density
en p-p
en
in
0.1 Hz to 10 Hz
f = 1 kHz
1.3
36
0.01
μV p-p
nV/√Hz
pA/√Hz
Rev. 0 | Page 3 of 16
AD8682/AD8684
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter
THERMAL RESISTANCE
Rating
Supply Voltage
18 V
Table 3.
Input Voltage
18 V
36 V
Package Type
θJA
θJC
45
43
35
36
Unit
°C/W
°C/W
°C/W
°C/W
Differential Input Voltage1
Output Short-Circuit Duration
Storage Temperature Range
Operating Temperature Range
Junction Temperature Range
Lead Temperature (Soldering, 60 sec)
8-Lead MSOP [RM-8]
8-Lead SOIC_N [R-8]
14-Lead TSSOP [RU-14]
14-Lead SOIC [R-14]
210
158
180
120
Indefinite
−65°C to +150°C
−40°C to +85°C
−65°C to +150°C
300°C
ESD CAUTION
1 For supply voltages less than 18 V, the absolute maximum input voltage is
equal to the supply voltage.
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.
Rev. 0 | Page 4 of 16
AD8682/AD8684
TYPICAL PERFORMANCE CHARACTERISTIC
80
180
135
90
70
60
V
= ±15V
= 25°C
V
T
= ±15V
= 25°C
S
S
T
A
A
60
50
A
A
= 100
= 10
VCL
40
40
30
VCL
20
45
20
10
A
= 1
0
0
VCL
0
–10
–20
–30
–20
–40
–45
–90
1k
10k
100k
1M
10M
1k
10k
100k
1M
10M
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 3. AD8682 Open-Loop Gain and Phase vs. Frequency
Figure 6. AD8682 Closed-Loop Gain vs. Frequency
30
25
20
15
10
5
45
40
35
30
25
20
15
10
5
V
= ±15V
= 10kΩ
= 50pF
S
V
R
= ±15V
= 10kΩ
S
L
R
L
C
L
–SR
+SR
0
–75
0
–75
–50
–25
0
25
50
75
100
125
–50
–25
0
25
50
75
100
125
TEMPERATURE (°C)
TEMPERATURE (°C)
Figure 7. Slew Rate vs. Temperature
Figure 4. AD8682 Open-Loop Gain vs. Temperature
1000
100
10
80
70
60
50
40
30
20
10
0
V
V
= ±15V
V
R
= ±15V
= 2kΩ
= 100mV p-p
S
S
= 0V
CM
L
V
IN
A
= 1
VCL
= 25°C
T
A
+OS
–OS
1
0.1
–75
–50
–25
0
25
50
75
100
125
0
100
200
300
400
500
TEMPERATURE (°C)
LOAD CAPACITANCE (pF)
Figure 8. AD8682 Input Bias Current vs. Temperature
Figure 5. Small Signal Overshoot vs. Load Capacitance
Rev. 0 | Page 5 of 16
AD8682/AD8684
1000
20
15
T
R
= 25°C
= 10kΩ
V
T
= ±15V
= 25°C
A
S
L
A
V
OH
10
100
10
5
0
–5
–10
–15
–20
V
OL
1
10
0
±5
±10
SUPPLY VOLTAGE (V)
±15
±20
100
FREQUENCY (Hz)
1k
10k
Figure 9. Voltage Noise Density vs. Frequency
Figure 12. Output Voltage Swing vs. Supply Voltage
1000
100
10
1000
100
10
V
T
= ±15V
= 25°C
V
T
= ±15V
= 25°C
S
S
A
A
A
= 100
VCL
VCL
A
= 10
= 1
1
1
A
VCL
0.1
0.1
100
–15
–10
–5
0
5
10
15
1k
10k
100k
1M
COMMON-MODE VOLTAGE (V)
FREQUENCY (Hz)
Figure 10. Input Bias Current vs. Common-Mode Voltage
Figure 13. Closed-Loop Output Impedance vs. Frequency
480
475
470
465
460
455
450
480
T
= 25°C
A
475
470
465
460
455
450
0
±5
±10
±15
±20
–50
–25
0
25
50
75
100
125
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
Figure 11. AD8682 Supply Current vs. Supply Voltage
Figure 14. AD8682 Supply Current vs. Temperature
Rev. 0 | Page 6 of 16
AD8682/AD8684
30
25
20
15
10
5
16
14
12
10
8
V
T
= ±15V
= 25°C
V
T
R
A
= ±15V
= 25°C
= 10kΩ
= 1
S
S
A
A
L
V
OL
V
VCL
OH
6
4
2
0
100
0
100
1k
10k
100k
1M
1k
LOAD RESISTANCE (Ω)
10k
FREQUENCY (Hz)
Figure 15. Absolute Output Voltage vs. Load Resistance
Figure 18. Maximum Output Swing vs. Frequency
140
120
100
80
140
120
100
80
V
T
= ±15V
= 25°C
S
V
T
= ±15V
= 25°C
S
A
A
+PSRR
60
60
40
40
20
–PSRR
20
0
0
–20
–40
–60
–20
–40
–60
100
1k
10k
100k
1M
100
1k
10k
100k
1M
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 19. AD8682 CMRR vs. Frequency
Figure 16. AD8682 PSRR vs. Frequency
20
18
14
12
10
8
V
T
= ±15V
= 25°C
S
V
= ±15V
= 25°C
S
A
T
A
100 ×AD8682
(200 OP AMPS)
16
14
12
SINK
10
8
SOURCE
6
6
4
4
2
2
0
0
–50
–25
0
25
50
75
100
125
–1.0 –0.8 –0.6 –0.4 –0.2
0
0.2
0.4
0.6
0.8
1.0
V
(µV)
TEMPERATURE (°C)
OS
Figure 20. AD8682 VOS Distribution
Figure 17. AD8682 Short-Circuit Current vs. Temperature
Rev. 0 | Page 7 of 16
AD8682/AD8684
400
360
320
280
240
200
160
120
80
1000
100
10
V
= ±15V
S
300 × OP282
(600 OP AMPS)
1
40
0
0.1
–75
–50
–25
0
25
50
75
100
125
0
4
8
12
16
20
24
28
32
36
TEMPERATURE (°C)
TCV (µV/°C)
OS
Figure 21. AD8682 TCVOS Distribution SOIC_N Package
Figure 24. AD8684 Input Bias Current vs. Temperature
50
45
950
945
40
35
30
940
935
930
25
20
15
925
920
915
910
10
5
0
–50
–25
0
25
50
75
100
125
0
10
20
30
40
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
Figure 22. AD8684 Open-Loop Gain vs. Temperature
Figure 25. AD8684 Relative Supply Current vs. Supply Voltage
950
945
60
50
V
T
= ±15V
= 25°C
S
A
A
= 100
= 10
= 1
VCL
940
935
40
30
A
VCL
930
925
20
10
A
VCL
920
915
910
0
–10
–20
–50
–25
0
25
50
75
100
125
1k
10k
100k
1M
10M
100M
FREQUENCY (Hz)
TEMPERATURE (°C)
Figure 23. AD8684 Closed-Loop Gain vs. Frequency
Figure 26. AD8684 Supply Current vs. Temperature
Rev. 0 | Page 8 of 16
AD8682/AD8684
140
120
100
80
40
35
30
V
= ±15V
= 25°C
S
V
= ±15V
S
T
A
100 × AD8684
(400 OP AMPS)
PSRR+
25
20
15
PSRR–
60
40
10
5
20
0
0
1k
10k
100k
FREQUENCY (Hz)
1M
10M
–1.0 –0.8 –0.6 –0.4 –0.2
0
0.2
0.4
0.6
0.8 1.0
V
(µV)
OS
Figure 27. AD8684 PSRR vs. Frequency
Figure 30. AD8684 VOS Distribution Package
14
12
800
700
600
V
= ±15V
S
300 × OP282
(1200 OP AMPS)
SINK
10
SOURCE
500
400
300
8
6
4
200
100
0
2
0
–50
–25
0
25
50
75
100
125
0
4
8
12 16 20 24 28 32 36 40 44 48 52 56 60
TEMPERATURE (°C)
TCV (µV/°C)
OS
Figure 28. AD8684 Short-Circuit Current vs. Temperature
Figure 31. AD8684 TCVOS Distribution Package
140
120
100
80
V
= ±15V
S
60
40
20
0
1k
10k
100k
1M
10M
FREQUENCY (Hz)
Figure 29. AD8684 CMRR vs. Frequency
Rev. 0 | Page 9 of 16
AD8682/AD8684
APPLICATIONS INFORMATION
The AD8682 and AD8684 are dual and quad JFET op amps that
are optimized for high speed at low power. This combination
makes these amplifiers excellent choices for battery-powered or
low power applications that require above average performance.
Applications benefiting from this performance combination
include telecommunications, geophysical exploration, portable
medical equipment, and navigational instrumentation.
PHASE INVERSION
Most JFET input amplifiers invert the phase of the input signal
if either input exceeds the input common-mode range. For the
AD8682/AD8684, negative signals in excess of approximately
14 V cause phase inversion. This is caused by saturation of the
input stage leading to the forward-biasing of a drain-gate diode.
A simple fix for this in noninverting applications is to place
a resistor in series with the noninverting input. This limits the
amount of current through the forward-biased diode and prevents
shutting down of the output stage. For the AD8682/AD8684,
a value of 200 kΩ has been found to work; however, it adds
a significant amount of noise.
HIGH-SIDE SIGNAL CONDITIONING
There are many applications requiring the sensing of signals near
the positive rail. The AD8682 and the AD8684 were tested and
are guaranteed over a common-mode range (−11 V ≤ VCM
≤
+15 V) that includes the positive supply.
15
The AD8682/AD8684 are commonly used in the sensing of
power supply currents and in current sensing applications, such
as the partial circuit shown in Figure 32. In this circuit, the
voltage drop across a low value resistor, such as the 0.1 Ω shown
here, is amplified and compared to 7.5 V. The output can then
be used for current limiting.
10
5
0
0.1Ω
15V
500kΩ
–5
–10
–15
R
L
100kΩ
100kΩ
1/2
AD8682
–15
–10
–5
0
5
10
15
500kΩ
V
IN
Figure 33. AD8682 Phase Reversal
Figure 32. High-Side Signal Conditioning
ACTIVE FILTERS
The wide bandwidth and high slew rates of the AD8682/AD8684
make either one an excellent choice for many filter applications.
There are many active filter configurations, but the four most
popular configurations are: Butterworth, elliptical, Bessel, and
Chebyshev. Each type has a response that is optimized for a
given characteristic, as shown in Table 4.
Table 4.
Type
Selectivity
Moderate
Good
Best
Poor
Overshoot
Good
Moderate
Poor
Phase
Amplitude (Pass Band)
Maximum flat
Equal ripple
Amplitude (Stop Band)
Butterworth
Chebyshev
Elliptical
Nonlinear
Linear
Equal ripple
Equal ripple
Bessel (Thompson)
Best
Rev. 0 | Page 10 of 16
AD8682/AD8684
PROGRAMMABLE STATE VARIABLE FILTER
This cutoff frequency can be expressed as
The circuit shown in Figure 34 can be used to accurately program
the Q; the cutoff frequency, fC; and the gain of a 2-pole state
variable filter. The AD8684 has been used in this design because
of its high bandwidth, low power, and low noise. This circuit takes
only three packages to build because of the quad configuration
of the op amps and DACs.
1
D1
⎛
⎝
⎞
⎟
⎠
fc =
⎜
2πR1C1 256
where D1 is the digital code for the DAC.
The gain of this circuit is set by adjusting D3. The gain equation is
R4 D3
The DACs shown are used in voltage mode; therefore, many
values are dependent on the accuracy of the DAC only and not
on the absolute values of the DAC resistive ladders. As a result, this
makes the circuit unusually accurate for a programmable filter.
⎛
⎞
⎟
⎠
Gain =
⎜
R5 256
⎝
DAC 2 is used to set the Q of the circuit. Adjusting this DAC
controls the amount of feedback from the band-pass node to
the input summing node. Note that the digital value of the
DAC is in the numerator; therefore, zero code is not a valid
operating point.
Adjusting DAC 1 changes the signal amplitude across R1; therefore,
the DAC attenuation × R1 determines the amount of signal current
that charges the integrating capacitor, C1.
R2 256
⎛
⎞
⎟
⎠
Q =
⎜
R3 D2
⎝
R7
2kΩ
R4
2kΩ
V
IN
R5
2kΩ
C1
1000pF
1/4
AD8684
1/4
1/4
AD8684
DAC8408
R1
2kΩ
C1
1/4
AD8684
1000pF
1/4
DAC8408
1/4
AD8684
R1
2kΩ
1/4
AD8684
1/4
DAC8408
HIGH PASS
1/4
AD8684
LOW
PASS
R6
2kΩ
BAND PASS
R3
2kΩ
R2
2kΩ
1/4
AD8684
1/4
DAC8408
1/4
AD8684
Figure 34. Programmable State Variable Filter
Rev. 0 | Page 11 of 16
AD8682/AD8684
OUTLINE DIMENSIONS
5.00 (0.1968)
4.80 (0.1890)
8
1
5
4
6.20 (0.2440)
5.80 (0.2284)
4.00 (0.1574)
3.80 (0.1497)
0.50 (0.0196)
0.25 (0.0099)
1.27 (0.0500)
BSC
45°
1.75 (0.0688)
1.35 (0.0532)
0.25 (0.0098)
0.10 (0.0040)
8°
0°
0.51 (0.0201)
0.31 (0.0122)
COPLANARITY
0.10
1.27 (0.0500)
0.40 (0.0157)
0.25 (0.0098)
0.17 (0.0067)
SEATING
PLANE
COMPLIANT TO JEDEC STANDARDS MS-012-AA
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
Figure 35. 8-Lead Standard Small Outline Package [SOIC_N]
Narrow Body
(R-8)
Dimensions shown in millimeters and (inches)
3.20
3.00
2.80
8
1
5
4
5.15
4.90
4.65
3.20
3.00
2.80
PIN 1
0.65 BSC
0.95
0.85
0.75
1.10 MAX
0.80
0.60
0.40
8°
0°
0.15
0.00
0.38
0.22
0.23
0.08
SEATING
PLANE
COPLANARITY
0.10
COMPLIANT TO JEDEC STANDARDS MO-187-AA
Figure 36. 8-Lead Mini Small Outline Package [MSOP]
(RM-8)
Dimensions shown in millimeters
Rev. 0 | Page 12 of 16
AD8682/AD8684
8.75 (0.3445)
8.55 (0.3366)
8
7
14
1
6.20 (0.2441)
5.80 (0.2283)
4.00 (0.1575)
3.80 (0.1496)
1.27 (0.0500)
BSC
0.50 (0.0197)
0.25 (0.0098)
45°
1.75 (0.0689)
1.35 (0.0531)
0.25 (0.0098)
0.10 (0.0039)
8°
0°
COPLANARITY
0.10
SEATING
PLANE
1.27 (0.0500)
0.40 (0.0157)
0.51 (0.0201)
0.31 (0.0122)
0.25 (0.0098)
0.17 (0.0067)
COMPLIANT TO JEDEC STANDARDS MS-012-AB
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
Figure 37. 14-Lead Standard Small Outline Package [SOIC_N]
Narrow Body
(R-14)
Dimensions shown in millimeters and (inches)
5.10
5.00
4.90
14
8
7
4.50
4.40
4.30
6.40
BSC
1
PIN 1
0.65
BSC
1.05
1.00
0.80
0.20
0.09
1.20
MAX
0.75
0.60
0.45
8°
0°
0.15
0.05
0.30
0.19
SEATING
PLANE
COPLANARITY
0.10
COMPLIANT TO JEDEC STANDARDS MO-153-AB-1
Figure 38. 14-Lead Thin Shrink Small Outline Package [TSSOP]
(RU-14)
Dimensions shown in millimeters
ORDERING GUIDE
Model
Temperature Range
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
Package Description
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead MSOP
Package Option
R-8
R-8
Branding
AD8682ARZ1
AD8682ARZ-REEL1
AD8682ARZ-REEL71
AD8682ARMZ-R21
AD8682ARMZ-REEL1
AD8684ARZ1
R-8
RM-8
RM-8
R-14
R-14
R-14
A1K
A1K
8-Lead MSOP
14-Lead SOIC_N
14-Lead SOIC_N
14-Lead SOIC_N
14-Lead TSSOP
14-Lead TSSOP
AD8684ARZ-REEL1
AD8684ARZ-REEL71
AD8684ARUZ1
RU-14
RU-14
AD8684ARUZ_REEL1
1 Z= Pb-free part.
Rev. 0 | Page 13 of 16
AD8682/AD8684
NOTES
Rev. 0 | Page 14 of 16
AD8682/AD8684
NOTES
Rev. 0 | Page 15 of 16
AD8682/AD8684
NOTES
©2006 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D06278-0-10/06(0)
Rev. 0 | Page 16 of 16
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