Datasheet

ManualsBrandsANALOG DEVICES ManualsLinear ICsLinear IC - Op-amp, differential amplifier Differential SOIC 8

Very Low Distortion,

Precision Difference Amplifier

AD8274

Rev. C

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FEATURES

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

APPLICATIONS

ADC driver

High performance audio

Instrumentation amplifier building blocks

Level translators

Automatic test equipment

Sine/cosine encoders

FUNCTIONAL BLOCK DIAGRAM

3 1

12kΩ 6kΩ

12kΩ

–V

6kΩ

07362-001

Figure 1.

Table 1. Difference Amplifiers by Category

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.

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  load

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.

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.

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.

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.

Low

Distortion

High

Voltage

Single-Supply

Unidirectional

Single-Supply

Bidirectional

AD8270 AD628 AD8202 AD8205

AD8273 AD629 AD8203 AD8206

AD8274 AD8216

AMP03

Summary of content (16 pages)

PAGE 1
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.
PAGE 2
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 .....
PAGE 3
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.
PAGE 4
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.
PAGE 5
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.
PAGE 6
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.
PAGE 7
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.
PAGE 8
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.
PAGE 9
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.
PAGE 10
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.
PAGE 11
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.
PAGE 12
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.
PAGE 13
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.
PAGE 14
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.
PAGE 15
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.