AAVID AD8274ARMZ Very low distortion, precision difference amplifier Datasheet

Very Low Distortion,
Precision Difference Amplifier
AD8274
FEATURES
APPLICATIONS
ADC driver
High performance audio
Instrumentation amplifier building blocks
Level translators
Automatic test equipment
Sine/cosine encoders
FUNCTIONAL BLOCK DIAGRAM
+VS
7
2
12kΩ
6kΩ
5
6
3
6kΩ
12kΩ
1
4
–VS
07362-001
Very low distortion
0.00025% THD + N (20 kHz)
0.0015% THD + N (100 kHz)
Drives 600 Ω loads
Excellent gain accuracy
0.03% maximum gain error
2 ppm/°C maximum gain drift
Gain of ½ or 2
AC specifications
20 V/μs minimum slew rate
800 ns to 0.01% settling time
High accuracy dc performance
83 dB minimum CMRR
700 μV maximum offset voltage
8-lead SOIC and MSOP packages
Supply current: 2.6 mA maximum
Supply range: ±2.5 V to ±18 V
Figure 1.
Table 1. Difference Amplifiers by Category
Low
Distortion
AD8270
AD8273
AD8274
AMP03
High
Voltage
AD628
AD629
Single-Supply
Unidirectional
AD8202
AD8203
Single-Supply
Bidirectional
AD8205
AD8206
AD8216
GENERAL DESCRIPTION
The AD8274 is a difference amplifier that delivers excellent ac
and dc performance. Built on Analog Devices, Inc., proprietary
iPolar® process and laser-trimmed resistors, AD8274 achieves a
breakthrough in distortion vs. current consumption and has
excellent gain drift, gain accuracy, and CMRR.
With no external components, the AD8274 can be configured
as a G = ½ or G = 2 difference amplifier. For single-ended
applications that need high gain stability or low distortion
performance, the AD8274 can also be configured for several
gains ranging from −2 to +3.
Distortion in the audio band is an extremely low 0.00025%
(112 dB) at a gain of ½ and 0.00035% (109 dB) at a gain of 2
while driving a 600 Ω load
The excellent distortion and dc performance of the AD8274,
along with its high slew rate and bandwidth, make it an excellent
ADC driver. Because of the part’s high output drive, it also
makes a very good cable driver.
With supply voltages up to ±18 V (+36 V single supply), the
AD8274 is well suited for measuring large industrial signals.
Additionally, the part’s resistor divider architecture allows it to
measure voltages beyond the supplies.
The AD8274 only requires 2.6 mA maximum supply current. It
is specified over the industrial temperature range of −40°C to
+85°C and is fully RoHS compliant. For the dual version, see the
AD8273 data sheet.
Rev. C
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.
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 ©2008–2011 Analog Devices, Inc. All rights reserved.
AD8274
TABLE OF CONTENTS
Features .............................................................................................. 1
Pin Configurations and Function Description..............................5
Applications....................................................................................... 1
Typical Performance Characteristics ..............................................6
Functional Block Diagram .............................................................. 1
Theory of Operation ...................................................................... 12
General Description ......................................................................... 1
Circuit Information.................................................................... 12
Revision History ............................................................................... 2
Driving the AD8274................................................................... 12
Specifications..................................................................................... 3
Power Supplies ............................................................................ 12
Absolute Maximum Ratings............................................................ 4
Input Voltage Range................................................................... 12
Thermal Resistance ...................................................................... 4
Configurations............................................................................ 13
Maximum Power Dissipation ..................................................... 4
Driving Cabling .......................................................................... 14
Short-Circuit Current .................................................................. 4
Outline Dimensions ....................................................................... 15
ESD Caution.................................................................................. 4
Ordering Guide .......................................................................... 15
REVISION HISTORY
8/11—Rev. B to Rev. C
Changes to Input Voltage Range Parameter, Table 2 ................... 3
1/11—Rev. A to Rev. B
Changes to Impedance/Differential Parameter, Table 2.............. 3
Changes to Figure 17........................................................................ 8
Updated Outline Dimensions ....................................................... 15
12/08—Rev. 0 to Rev. A
Changes to Figure 8 and Figure 10................................................. 6
7/08—Revision 0: Initial Version
Rev. C | Page 2 of 16
AD8274
SPECIFICATIONS
VS = ±15 V, VREF = 0 V, TA = 25°C, RL = 2 kΩ, unless otherwise noted.
Table 2.
Parameter
DYNAMIC PERFORMANCE
Bandwidth
Slew Rate
Settling Time to 0.1%
Settling Time to 0.01%
NOISE/DISTORTION 1
THD + Noise
Noise Floor, RTO 2
Output Voltage Noise
(Referred to Output)
GAIN
Gain Error
Gain Drift
Gain Nonlinearity
INPUT CHARACTERISTICS
Offset 3
vs. Temperature
vs. Power Supply
Common-Mode Rejection
Ratio
Input Voltage Range 4
Impedance 5
Differential
Common Mode 6
OUTPUT CHARACTERISTICS
Output Swing
Short-Circuit Current Limit
Capacitive Load Drive
POWER SUPPLY
Supply Current (per
Amplifier)
TEMPERATURE RANGE
Specified Performance
Conditions
G=½
Typ
Min
Max
Min
20
G=2
Typ
Max
Unit
10
10 V step on output,
CL = 100 pF
10 V step on output,
CL = 100 pF
650
750
675
775
MHz
V/μs
ns
725
800
750
825
ns
f = 1 kHz,
VOUT = 10 V p-p,
600 Ω load
20 kHz BW
f = 20 Hz to 20 kHz
0.00025
0.00035
%
−106
3.5
−100
7
dBu
μV rms
f = 1 kHz
26
52
nV/√Hz
−40°C to +85°C
VOUT = 10 V p-p,
600 Ω load
0.5
2
Referred to output
−40°C to +85°C
VS = ±2.5 V to ±18 V
VCM = ±40 V,
RS = 0 Ω,
referred to input
150
3
20
20
0.03
2
0.5
2
700
300
6
5
77
86
3(−VS + 1.5)
VCM = 0 V
−VS + 1.5
−40
μV
μV/°C
μV/V
dB
1.5(+VS – 1.5)
9
9
+VS − 1.5
−VS + 1.5
90
60
200
2.3
1100
92
1.5(−VS + 1.5)
36
9
Sourcing
Sinking
%
ppm/°C
ppm
10
83
3(+VS − 1.5)
0.03
2
kΩ
kΩ
+VS − 1.5
V
mA
mA
pF
2.6
mA
+85
°C
90
60
1200
2.6
+85
1
2.3
−40
V
Includes amplifier voltage and current noise, as well as noise of internal resistors.
dBu = 20 log(V rms/0.7746).
Includes input bias and offset current errors.
4
May also be limited by absolute maximum input voltage or by the output swing. See the Absolute Maximum Ratings section and Figure 8 through Figure 11 for details.
5
Internal resistors are trimmed to be ratio matched but to have ±20% absolute accuracy.
6
Common mode is calculated by looking into both inputs. The common-mode impedance at only one input is 18 kΩ.
2
3
Rev. C | Page 3 of 16
AD8274
ABSOLUTE MAXIMUM RATINGS
MAXIMUM POWER DISSIPATION
Rating
±18 V
−VS + 40 V
+VS – 40 V
−65°C to +150°C
−40°C to +85°C
150°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.
THERMAL RESISTANCE
The θJA values in Table 4 assume a 4-layer JEDEC standard
board with zero airflow.
The maximum safe power dissipation for the AD8274 is limited
by the associated rise in junction temperature (TJ) on the die. At
approximately 150°C, which is the glass transition temperature,
the properties of the plastic change. Even temporarily exceeding
this temperature limit may change the stresses that the package
exerts on the die, permanently shifting the parametric performance
of the amplifiers. Exceeding a temperature of 150°C for an
extended period may result in a loss of functionality.
2.0
TJ MAX = 150°C
Table 4. Thermal Resistance
Package Type
8-Lead MSOP
8-Lead SOIC
θJA
135
121
Unit
°C/W
°C/W
1.6
SOIC
θJA = 121°C/W
1.2
MSOP
θJA = 135°C/W
0.8
0.4
0
–50
07362-004
Parameter
Supply Voltage
Maximum Voltage at Any Input Pin
Minimum Voltage at Any Input Pin
Storage Temperature Range
Specified Temperature Range
Package Glass Transition Temperature (TG)
MAXIMUM POWER DISSIPATION (W)
Table 3.
–25
0
25
50
75
100
125
AMBIENT TEMERATURE (°C)
Figure 2. Maximum Power Dissipation vs. Ambient Temperature
SHORT-CIRCUIT CURRENT
The AD8274 has built-in, short-circuit protection that limits the
output current (see Figure 16 for more information). While the
short-circuit condition itself does not damage the part, the heat
generated by the condition can cause the part to exceed its
maximum junction temperature, with corresponding negative
effects on reliability. Figure 2 and Figure 16, combined with
knowledge of the part’s supply voltages and ambient temperature,
can be used to determine whether a short circuit will cause the
part to exceed its maximum junction temperature.
ESD CAUTION
Rev. C | Page 4 of 16
AD8274
–IN 2
+IN 3
AD8274
TOP VIEW
(Not to Scale)
–VS 4
8
NC
REF 1
7
+VS
–IN 2
6
OUT
+IN 3
5
SENSE
NC = NO CONNECT
AD8274
TOP VIEW
–VS 4 (Not to Scale)
07362-002
REF 1
8
NC
7
+VS
6
OUT
5
SENSE
07362-003
PIN CONFIGURATIONS AND FUNCTION DESCRIPTION
NC = NO CONNECT
Figure 4. SOIC Pin Configuration
Figure 3. MSOP Pin Configuration
Table 5. Pin Function Descriptions
Pin No.
1
Mnemonic
REF
2
−IN
3
+IN
4
5
−VS
SENSE
6
7
8
OUT
+VS
NC
Description
6 kΩ Resistor to Noninverting Terminal of Op Amp. Used as reference pin in G = ½ configuration. Used as
positive input in G = 2 configuration.
12 kΩ Resistor to Inverting Terminal of Op Amp. Used as negative input in G = ½ configuration. Connect
to output in G = 2 configuration.
12 kΩ Resistor to Noninverting Terminal of Op Amp. Used as positive input in G = ½ configuration. Used
as reference pin in G = 2 configuration.
Negative Supply.
6 kΩ Resistor to Inverting Terminal of Op Amp. Connect to output in G = ½ configuration. Used as
negative input in G = 2 configuration.
Output.
Positive Supply.
No Connect.
Rev. C | Page 5 of 16
AD8274
TYPICAL PERFORMANCE CHARACTERISTICS
VS = ±15 V, TA = 25°C, gain = ½, difference amplifier configuration, unless otherwise noted.
30
20
G=½
0V, +25V
10
0
–5
–10
–15
–25
–30
–50
07362-106
–20
REPRESENTATIVE SAMPLES
–30
–10
10
30
50
70
90
110
VS = ±15V
10
–13.5V, +11.5V
+13.5V, +11.5V
–13.5V, –11.5V
+13.5V, –11.5V
0
–10
–20
0V, –25V
–30
–15
130
–10
–5
0
5
10
Figure 5. CMR vs. Temperature, Normalized at 25°C, Gain = ½
Figure 8. Input Common-Mode Voltage vs. Output Voltage,
Gain = ½, ±15 V Supplies
150
20
100
15
G=½
50
0
–50
–100
07362-107
–150
REPRESENTATIVE SAMPLES
–10
10
30
50
70
90
110
+3.5V, +8.8V
10
+1.0V, +4.2V
0
–1.0V, –4.0V
–5
+1.0, –6.0V
–10
–15
–3.5V, –8.7V
–3
+3.5V, –15.5V
–2
Figure 6. System Offset vs. Temperature, Normalized at 25°C,
Referred to Output, Gain = ½
25
INPUT COMMON-MODE VOLTAGE (V)
20
10
0
–10
–20
–30
07362-108
–40
REPRESENTATIVE SAMPLES
–30
–10
10
30
50
70
0
1
2
3
4
Figure 9. Input Common-Mode Voltage vs. Output Voltage,
Gain = ½, ±5 V and ±2.5 V Supplies
30
GAIN ERROR (µV/V)
–1
OUTPUT VOLTAGE (V)
TEMPERATURE (°C)
–50
–50
VS = ±2.5V
–1.0V, +6.2V
5
–20–4
130
VS = ±5V
90
110
0V, +20.85V
VS = ±15V
15
10
–13.5V, +11.5V
+13.5V, +11.5V
–13.5V, –11.5V
+13.5V, –11.5V
5
0
–5
–10
–15
–20
–25
–15
130
G=2
20
07362-111
–30
INPUT COMMON-MODE VOLTAGE (V)
SYSTEM OFFSET (µV)
–3.5V, +15.8V
–200
–50
15
OUTPUT VOLTAGE (V)
TEMPERATURE (°C)
07362-110
CMR (µV/V)
5
20
07362-210
INPUT COMMON-MODE VOLTAGE (V)
15
0V, –20.85V
–10
–5
0
5
10
15
OUTPUT VOLTAGE (V)
TEMPERATURE (°C)
Figure 10. Input Common-Mode Voltage vs. Output Voltage,
Gain = 2, ±15 V Supplies
Figure 7. Gain Error vs. Temperature, Normalized at 25°C, Gain = ½
Rev. C | Page 6 of 16
AD8274
–3.5V, +6.9V
6
10
G=2
VS = ±5V
G=2
+3.5V, +5.2V
5
4
–1.0V, +2.7V
VS = ±2.5V
0
+1.0V, +2.2V
GAIN (dB)
2
0
–1.0V, –2.0V
–2
+1.0, –2.6V
G=½
–5
–10
–4
+3.5V, –6.9V
–8–4
–3
–2
–1
0
1
2
3
–20
100
4
1k
10k
OUTPUT VOLTAGE (V)
100k
1M
10M
100M
FREQUENCY(Hz)
Figure 11. Input Common-Mode Voltage vs. Output Voltage,
Gain = 2, ±5 V and ±2.5 V Supplies
07362-007
–15
–3.5V, –5.2V
–6
07362-112
INPUT COMMON-MODE VOLTAGE (V)
8
Figure 14. Gain vs. Frequency
140
120
120
100
GAIN = ½
NEGATIVE PSRR
CMRR (dB)
80
80
60
60
40
40
1
10
100
1k
10k
100k
1M
FREQUENCY (Hz)
0
10
Figure 12. Power Supply Rejection Ratio vs. Frequency,
Gain = ½, Referred to Output
10k
100k
1M
Figure 15. Common-Mode Rejection Ratio vs. Frequency, Referred to Input
120
±15V SUPPLY
20
16
12
±5V SUPPLY
4
SOURCING
80
60
40
20
0
–20
–40
SINKING
–60
07362-117
SHORT-CIRCUIT CURRENT (mA)
100
24
8
1k
FREQUENCY (Hz)
32
28
100
07362-217
20
20
0
–80
0
100
1k
10k
100k
1M
FREQUENCY (Hz)
10M
–100
–40
07362-006
MAXIMUM OUTPUT VOLTAGE (V p-p)
GAIN = 2
100
07362-021
POWER SUPPLY REJECTION (dB)
POSITIVE PSRR
–20
0
20
40
60
80
100
TEMPERATURE (°C)
Figure 16. Short-Circuit Current vs. Temperature
Figure 13. Maximum Output Voltage vs. Frequency
Rev. C | Page 7 of 16
120
AD8274
+85°C
+125°C
+VS – 2
CL = 100pF
+25°C
–40°C
+VS – 4
50mV/DIV
OUTPUT VOLTAGE SWING (V)
+VS
0
–VS + 4
NO LOAD
+125°C
600Ω
2kΩ
–40°C +25°C
+85°C
200
1k
LOAD RESISTANCE (Ω)
10k
07362-009
–VS
1µs/DIV
Figure 20. Small-Signal Step Response, Gain = ½
Figure 17. Output Voltage Swing vs. RL, VS = ±15 V
+VS
07362-025
–VS + 2
–40°C
+25°C
+125°C
+85°C
50mV/DIV
+VS – 6
+125°C
–VS + 6
+85°C
+25°C
–40°C
0
20
40
60
80
100
CURRENT (mA)
07362-023
–VS
1µs/DIV
07362-026
–VS + 3
Figure 21. Small-Signal Pulse Response with 500 pF Capacitor Load,
Gain = 2
Figure 18. Output Voltage vs. IOUT
50mV/DIV
CL = 100pF
NO LOAD
2kΩ
1µs/DIV
07362-024
600Ω
1µs/DIV
07362-027
50mV/DIV
OUTPUT VOLTAGE (V)
+VS – 3
Figure 22. Small-Signal Pulse Response for 100 pF Capacitive Load,
Gain = ½
Figure 19. Small-Signal Step Response, Gain = 2
Rev. C | Page 8 of 16
AD8274
100
100
80
80
5V
70
70
60
OVERSHOOT (%)
15V
18V
50
40
40
30
20
20
10
10
0
20
40
60
80
100
120
140
160
180
200
CAPACITIVE LOAD (pF)
5V 15V
50
30
0
2.5V
60
0
07362-037
OVERSHOOT (%)
90
2.5V
18V
0
200
400
600
800
1000
1200
CAPACITIVE LOAD (pF)
Figure 26. Small-Signal Overshoot vs. Capacitive Load,
Gain = 2, 600 Ω in Parallel with Capacitive Load
Figure 23. Small-Signal Overshoot vs. Capacitive Load,
Gain = ½, No Resistive Load
100
90
80
2.5V
5V
15V
60
2V/DIV
OVERSHOOT (%)
70
18V
50
40
30
0
0
20
40
60
80
100
120
140
160
180
200
CAPACITIVE LOAD (pF)
07362-038
10
1µs/DIV
Figure 24. Small-Signal Overshoot vs. Capacitive Load,
Gain = ½, 600 Ω in Parallel with Capacitive Load
07362-032
20
Figure 27. Large-Signal Pulse Response,
Gain = ½
100
90
80
2.5V
60
15V
2V/DIV
5V
50
18V
40
30
20
0
0
200
400
600
800
1000
CAPACITIVE LOAD (pF)
1200
1µs/DIV
Figure 28. Large-Signal Pulse Response,
Gain = 2
Figure 25. Small-Signal Overshoot vs. Capacitive Load,
Gain = 2, No Resistive Load
Rev. C | Page 9 of 16
07362-033
10
07362-039
OVERSHOOT (%)
70
07362-040
90
AD8274
40
0.1
22kHz FILTER
VOUT = 10V p-p
RL = 600Ω
35
0.01
25
THDN + N (%)
SLEW RATE (V/µS)
30
+SR
20
–SR
15
0.001
10
GAIN = 2
5
0
20
40
60
80
100
120
TEMPERATURE (°C)
07362-010
–20
0.0001
10
100
1k
FREQUENCY (Hz)
10k
100k
07362-131
GAIN = ½
0
–40
Figure 32. THD + N vs. Frequency, Filter = 22k Hz
Figure 29. Slew Rate vs. Temperature
0.1
10k
1k
THD + N (%)
0.01
GAIN = 2
0.001
GAIN = 2
GAIN = ½
GAIN = ½
1
10
100
1k
10k
100k
FREQUENCY (Hz)
0.0001
10
07362-034
10
100
1k
FREQUENCY (Hz)
100k
10k
07362-135
100
Figure 33. THD + N vs. Frequency, Filter = 120 kHz
Figure 30. Voltage Noise Density vs. Frequency, Referred to Output
1
GAIN = ½
f = 1kHz
G=2
G=½
RL = 2kΩ, 100Ω
0.01
RL = 600Ω
1s/DIV
07362-035
0.001
0.0001
0
5
10
15
OUTPUT AMPLITUDE (dBu)
20
Figure 34. THD + N vs. Output Amplitude, G = ½
Figure 31. 0.1 Hz to 10 Hz Voltage Noise, RTO
Rev. C | Page 10 of 16
25
07362-136
THD + N (%)
0.1
1µV/DIV
VOLTAGE NOISE DENSITY (nV/√Hz)
VOUT = 10V p-p
AD8274
1
0.1
GAIN = 2
f = 1kHz
THD + N (%)
0.1
0.01
RL = 600Ω
RL = 2kΩ
RL = 100kΩ
0.0001
0
5
10
15
OUTPUT AMPLITUDE (dBu)
20
25
07362-137
0.001
Figure 35. THD + N vs. Output Amplitude, G = 2
0.01
0.001
THIRD HARMONIC ALL LOADS
SECOND HARMONIC R L = 600Ω
SECOND HARMONIC R L = 100kΩ, 2kΩ
100
1k
FREQUENCY (Hz)
10k
100k
07362-138
AMPLITUDE (% OF FUNDAMENTAL)
GAIN = ½
VOUT = 10V p-p
0.00001
10
0.001
THIRD HARMONIC ALL LOADS
0.0001
SECOND HARMONIC R L = 600Ω
SECOND HARMONIC R L = 100kΩ, 2kΩ
0.00001
10
100
1k
FREQUENCY (Hz)
10k
100k
Figure 37. Harmonic Distortion Products vs. Frequency, G = 2
0.1
0.0001
0.01
Figure 36. Harmonic Distortion Products vs. Frequency, G = ½
Rev. C | Page 11 of 16
07362-139
AMPLITUDE (% OF FUNDAMENTAL)
GAIN = 2
VOUT = 10V p-p
AD8274
THEORY OF OPERATION
+VS
DRIVING THE AD8274
7
12kΩ
The AD8274 is easy to drive, with all configurations presenting
at least several kilohms (kΩ) of input resistance. The AD8274
should be driven with a low impedance source: for example,
another amplifier. The gain accuracy and common-mode rejection
of the AD8274 depend on the matching of its resistors. Even
source resistance of a few ohms can have a substantial effect on
these specifications.
6kΩ
5
6
12kΩ
6kΩ
4
–VS
1
07362-001
3
POWER SUPPLIES
Figure 38. Functional Block Diagram
CIRCUIT INFORMATION
The AD8274 consists of a high precision, low distortion op amp
and four trimmed resistors. These resistors can be connected to
make a wide variety of amplifier configurations, including
difference, noninverting, and inverting configurations. Using
the on-chip resistors of the AD8274 provides the designer with
several advantages over a discrete design.
DC Performance
Much of the dc performance of op amp circuits depends on the
accuracy of the surrounding resistors. The resistors on the AD8274
are laid out to be tightly matched. The resistors of each part are
laser trimmed and tested for their matching accuracy. Because
of this trimming and testing, the AD8274 can guarantee high
accuracy for specifications such as gain drift, common-mode
rejection, and gain error.
AC Performance
Because feature size is much smaller in an integrated circuit than
on a printed circuit board (PCB), the corresponding parasitics are
also smaller. The smaller feature size helps the ac performance of
the AD8274. For example, the positive and negative input terminals
of the AD8274 op amp are not pinned out intentionally. By not
connecting these nodes to the traces on the PCB, the capacitance
remains low, resulting in both improved loop stability and
common-mode rejection over frequency.
A stable dc voltage should be used to power the AD8274. Noise
on the supply pins can adversely affect performance. A bypass
capacitor of 0.1 μF should be placed between each supply pin
and ground, as close as possible to each supply pin. A tantalum
capacitor of 10 μF should also be used between each supply and
ground. It can be farther away from the supply pins and, typically,
it can be shared by other precision integrated circuits.
The AD8274 is specified at ±15 V, but it can be used with
unbalanced supplies, as well. For example, −VS = 0 V, +VS = 20 V.
The difference between the two supplies must be kept below 36 V.
INPUT VOLTAGE RANGE
The AD8274 can measure voltages beyond the rails. For the G = ½
and G = 2 difference amplifier configurations, see the input voltage
range in Table 2 for specifications.
The AD8274 is able to measure beyond the rail because the
internal resistors divide down the voltage before it reaches the
internal op amp. Figure 39 shows an example of how the voltage
division works in the difference amplifier configuration. For the
AD8274 to measure correctly, the input voltages at the internal
op amp must stay within 1.5 V of either supply rail.
R2 (V )
R1 + R2 IN+
R4
R3
R1
R2
Production Costs
Because one part, rather than several, is placed on the PCB, the
board can be built more quickly.
Size
The AD8274 fits a precision op amp and four resistors in one
8-lead MSOP or SOIC package.
R2 (V )
R1 + R2 IN+
07362-061
2
Figure 39. Voltage Division in the Difference Amplifier Configuration
For best long-term reliability of the part, voltages at any of the
part’s inputs (Pin 1, Pin 2, Pin 3, or Pin 5) should stay within
+VS – 40 V to −VS + 40 V. For example, on ±10 V supplies,
input voltages should not exceed ±30 V.
Rev. C | Page 12 of 16
AD8274
CONFIGURATIONS
The AD8274 can be configured in several ways; see Figure 40 to Figure 47. Because these configurations rely on the internal, matched
resistors, all of these configurations have excellent gain accuracy and gain drift. Note that the AD8274 internal op amp is stable for noise
gains of 1.5 and higher, so the AD8274 should not be placed in a unity-gain follower configuration.
6kΩ
OUT
1
VOUT = ½ (VIN+ − VIN−)
+IN
6kΩ
12kΩ
2
6
1
+IN
6kΩ
12kΩ
1
3
6kΩ
+IN
OUT
3
1
+IN
07362-013
12kΩ
5
OUT
6kΩ
3 12kΩ
VOUT = 1½ VIN
Figure 46. Noninverting Amplifier, G = 1.5
2
6
6kΩ
6
5
6kΩ
OUT
12kΩ
2
6
OUT
3 12kΩ
+IN
6kΩ
VOUT = –2 VIN
12kΩ
OUT
07362-017
3
6kΩ
1
2 12kΩ
Figure 42. Inverting Amplifier, G = −½
1 12kΩ
2
Figure 45. Noninverting Amplifier, G = 2
5
6
6kΩ
6kΩ
12kΩ
6
VOUT = –½ VIN
5
1
VOUT = 2 VIN
3 12kΩ
–IN
6kΩ
OUT
Figure 41. Difference Amplifier, G = 2
2 12kΩ
6kΩ
5
VOUT = 2 (VIN+ − VIN−)
–IN
3 12kΩ
Figure 44. Noninverting Amplifier, G = ½
07362-016
5
OUT
VOUT = ½ VIN
Figure 40. Difference Amplifier, G = ½
–IN
5
6
07362-012
3 12kΩ
6kΩ
07362-015
6
+IN
2 12kΩ
5
07362-019
6kΩ
07362-014
2 12kΩ
1
VOUT = 3 VIN
6kΩ
07362-018
–IN
Figure 47. Noninverting Amplifier, G = 3
Figure 43. Inverting Amplifier, G = −2
Rev. C | Page 13 of 16
AD8274
DRIVING CABLING
Because the AD8274 can drive large voltages at high output
currents and slew rates, it makes an excellent cable driver. It is
good practice to put a small value resistor between the AD8274
output and cable, since capacitance in the cable can cause peaking
or instability in the output response. A resistance of 20 Ω or higher
is recommended.
R ≥ 20Ω
06979-060
AD8274
Figure 48. Driving Cabling
Rev. C | Page 14 of 16
AD8274
OUTLINE DIMENSIONS
5.00 (0.1968)
4.80 (0.1890)
8
4.00 (0.1574)
3.80 (0.1497)
5
1
4
1.27 (0.0500)
BSC
0.25 (0.0098)
0.10 (0.0040)
6.20 (0.2441)
5.80 (0.2284)
1.75 (0.0688)
1.35 (0.0532)
0.51 (0.0201)
0.31 (0.0122)
COPLANARITY
0.10
SEATING
PLANE
0.50 (0.0196)
0.25 (0.0099)
45°
8°
0°
0.25 (0.0098)
0.17 (0.0067)
1.27 (0.0500)
0.40 (0.0157)
012407-A
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 49. 8-Lead Standard Small Outline Package [SOIC_N]
Narrow Body (R-8)
Dimensions shown in millimeters and (inches)
3.20
3.00
2.80
3.20
3.00
2.80
8
1
5.15
4.90
4.65
5
4
PIN 1
IDENTIFIER
0.65 BSC
0.95
0.85
0.75
15° MAX
1.10 MAX
0.40
0.25
6°
0°
0.23
0.09
COMPLIANT TO JEDEC STANDARDS MO-187-AA
0.80
0.55
0.40
10-07-2009-B
0.15
0.05
COPLANARITY
0.10
Figure 50. 8-Lead Mini Small Outline Package [MSOP]
(RM-8)
Dimensions shown in millimeters
ORDERING GUIDE
Model 1
AD8274ARZ
AD8274ARZ-R7
AD8274ARZ-RL
AD8274ARMZ
AD8274ARMZ-R7
AD8274ARMZ-RL
1
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
Package Description
8-Lead SOIC_N
8-Lead SOIC_N, 7" Tape and Reel
8-Lead SOIC_N, 13" Tape and Reel
8-Lead MSOP
8-Lead MSOP, 7" Tape and Reel
8-Lead MSOP, 13" Tape and Reel
Z = RoHS Compliant Part.
Rev. C | Page 15 of 16
Package Option
R-8
R-8
R-8
RM-8
RM-8
RM-8
Branding
Y1B
Y1B
Y1B
AD8274
NOTES
©2008–2011 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D07362-0-8/11(C)
Rev. C | Page 16 of 16