AD623

AD623 (Rev. G)

Document overview

• Manufacturer or author: Analog Devices, Inc.
• PDF pages: 32

Technical content

Single and Dual-Supply, Rail-to-Rail, Low Cost Instrumentation Amplifier Data Sheet AD623 Rev. G Document Feedback 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. Tel: 781.329.4700 ©2020 Analog Devices, Inc. All rights reserved. Technical Support www.analog.com

FEATURES

Input voltage range extends 150 mV below ground (single supply) Low power, 550 µA maximum quiescent current Gain set with one external resistor Gain range: 1 to 1000 High accuracy dc performance 0.10% gain error (G = 1) 0.35% gain error (G > 1) Noise: 35 nV/√Hz RTI noise at 1 kHz Optimal dynamic specifications 800 kHz bandwidth (G = 1) 20 µs settling time to 0.01% (G = 10)

APPLICATIONS

Low power medical instrumentation Transducer interfaces Thermocouple amplifiers Industrial process controls Difference amplifiers Low power data acquisition GENERAL DESCRIPTION The AD623 is an integrated, single- or dual-supply instrumentation amplifier that delivers rail-to-rail output swing using supply voltages from 2.7 V to 12 V. T h e AD623 offers user flexibility by allowing single gain set resistor programming and by conforming to the 8-lead industry standard pinout configuration. With no external resistor, the AD623 is configured for unity gain (G = 1), and with an external resistor, the AD623 can be programmed for gains of up to 1000. The accuracy of the AD623 is the result of increasing ac common-mode rejection ratio (CMRR) coincident with increasing gain. Line noise harmonics are rejected due to constant CMRR up to 200 Hz. The AD623 has a wide input common-mode range and amplifies signals with common- mode voltages as low as 150 mV below ground. The AD623 maintains optimal performance with dual and single polarity power supplies. Table 1. Low Power Upgrades for the AD623

Rev. G | Page 3 of 32 7/2008—Rev. C to Rev. D Changes to Features Section and General Description Section .. 1 9/1999—Rev. B to Rev. C

Rev. G | Page 4 of 32 SPECIFICATIONS SINGLE SUPPLY Typical at 25°C, single supply, +VS = 5 V , −VS = 0 V, a n d load resistance (RL) = 10 kΩ, unless otherwise noted. Table 2. Test Conditions/ Comments AD623ANZ, AD623ARZ AD623ARM AD623BNZ, AD623BRZ Parameter Min Typ Max Min Typ Max Min Typ Max Unit GAIN G = 1 + (100 k/external resistor (RG)) Gain Range 1 1000 1 1000 1 1000 Gain Error1 G1 output voltage (VOUT) = 0.15 V to 3.5 V G > 1 VOUT = 0.15 V to 4.5 V Nonlinearity G1 VOUT = 0.15 V to 3.5 V G > 1 VOUT = 0.15 V to 4.5 V G = 1 to 1000 50 50 50 ppm Gain vs. Temperature G = 1 5 10 5 10 5 10 ppm/°C G > 11 50 50 50 ppm/°C VOLTAGE OFFSET Total referred to input (RTI) error = VOSI + VOSO/G Input Offset, VOSI 25 200 200 500 25 100 µV Over Temperature 350 650 160 µV Average Temperature Coefficient (Tempco) 0.1 2 0.1 2 0.1 1 µV/°C Output Offset, VOSO 200 1000 500 2000 200 500 µV Over Temperature 1500 2600 1100 µV Average Tempco 2.5 10 2.5 10 2.5 10 µV/°C Offset Referred to the Input vs. Supply (PSR) G = 1 80 100 80 100 80 100 dB G = 10 100 120 100 120 100 120 dB G = 100 100 130 100 130 100 130 dB G = 1000 100 130 100 130 100 130 dB INPUT CURRENT Input Bias Current 17 25 17 25 17 25 nA Over Temperature 27.5 27.5 27.5 nA Average Tempco 25 25 25 pA/°C Input Offset Current 0.25 2 0.25 2 0.25 2 nA Over Temperature 2.5 2.5 2.5 nA Average Tempco 5 5 5 pA/°C

Rev. G | Page 5 of 32 Test Conditions/ Comments AD623ANZ, AD623ARZ AD623ARM AD623BNZ, AD623BRZ Parameter Min Typ Max Min Typ Max Min Typ Max Unit INPUT Input Impedance Input Voltage Range2 VS = 3 V to 12 V (−VS) − 0.15 (+VS) − 1.5 (−VS) − 0.15 (+VS) − 1.5 (−VS) − 0.15 (+VS) − 1.5 V Common-Mode Rejection at 60 Hz with 1 kΩ Source Imbalance G = 1 Common-mode voltage (VCM) = 0 V to 3 V 70 80 70 80 77 86 dB G = 10 VCM = 0 V to 3 V 90 100 90 100 94 100 dB G = 100 VCM = 0 V to 3 V 105 110 105 110 105 110 dB G = 1000 VCM = 0 V to 3 V 105 110 105 110 105 110 dB OUTPUT Output Swing RL = 10 kΩ 0.2 (+VS) − 0.5 0.2 (+VS) − 0.5 0.2 (+VS) − 0.5 V RL = 100 kΩ 0.05 (+VS) − 0.15 0.05 (+VS) − 0.15 0.05 (+VS) − 0.15 V DYNAMIC RESPONSE Small Signal −3 dB Bandwidth G = 1 800 800 800 kHz G = 10 100 100 100 kHz G = 100 10 10 10 kHz G = 1000 2 2 2 kHz Slew Rate 0.3 0.3 0.3 V/µs Settling Time to 0.01% VS = 5 V G = 1 Step size = 3.5 V 30 30 30 µs G = 10 Step size = 4 V, VCM = 1.8 V 20 20 20 µs 1 Does not include effects of external resistor, RG. 2 One input grounded. G = 1.

Rev. G | Page 6 of 32 DUAL SUPPLIES Typical at 25°C dual supply, VS = ±5 V , and RL = 10 kΩ, unless otherwise noted. Table 3. Test Conditions/ Comments AD623ANZ, AD623ARZ AD623ARM AD623BNZ, AD623BRZ Parameter Min Typ Max Min Typ Max Min Typ Max Unit GAIN G = 1 + (100 k/RG) Gain Range 1 1000 1 1000 1 1000 Gain Error1 G1 VOUT = −4.8 V to +3.5 V G > 1 VOUT = −4.8 V to 4.5 V Nonlinearity G1 VOUT = −4.8 V to +3.5 V G > 1 VOUT = −4.8 V to +4.5 V G = 1 to 1000 50 50 50 ppm Gain vs. Temperature G = 1 5 10 5 10 5 10 ppm/°C G > 11 50 50 50 ppm/°C VOLTAGE OFFSET Total RTI error = VOSI + VOSO/G Input Offset, VOSI 25 200 200 500 25 100 µV Over Temperature 350 650 160 µV Average Tempco 0.1 2 0.1 2 0.1 1 µV/°C Output Offset, VOSO 200 1000 500 2000 200 500 µV Over Temperature 1500 2600 1100 µV Average Tempco 2.5 10 2.5 10 2.5 10 µV/°C Offset Referred to the Input vs. Supply (PSR) G = 1 80 100 80 100 80 100 dB G = 10 100 120 100 120 100 120 dB G = 100 100 130 100 130 100 130 dB G = 1000 100 130 100 130 100 130 dB INPUT CURRENT Input Bias Current 17 25 17 25 17 25 nA Over Temperature 27.5 27.5 27.5 nA Average Tempco 25 25 25 pA/°C Input Offset Current 0.25 2 0.25 2 0.25 2 nA Over Temperature 2.5 2.5 2.5 nA Average Tempco 5 5 5 pA/°C INPUT Input Impedance Input Voltage Range2 VS = +2.5 V to ±6 V (−VS) – 0.15 (+VS) – 1.5 (−VS) – 0.15 (+VS) – 1.5 (−VS) – 0.15 (+VS) – 1.5 V

Rev. G | Page 7 of 32 Test Conditions/ Comments AD623ANZ, AD623ARZ AD623ARM AD623BNZ, AD623BRZ Parameter Min Typ Max Min Typ Max Min Typ Max Unit Common-Mode Rejection at 60 Hz with 1 kΩ Source Imbalance G = 1 VCM = +3.5 V to −5.15 V 70 80 70 80 77 86 dB G = 10 VCM = +3.5 V to −5.15 V 90 100 90 100 94 100 dB G = 100 VCM = +3.5 V to −5.15 V 105 110 105 110 105 110 dB G = 1000 VCM = +3.5 V to −5.15 V 105 110 105 110 105 110 dB OUTPUT Output Swing RL = 10 kΩ, VS = ±5 V (−VS) + 0.2 (+VS) − 0.5 (−VS) + 0.2 (+VS) − 0.5 (−VS) + 0.2 (+VS) − 0.5 V RL = 100 kΩ (−VS) + 0.05 (+VS) − 0.15 (−VS) + 0.05 (+VS) − 0.15 (−VS) + 0.05 (+VS) − 0.15 V DYNAMIC RESPONSE Small Signal −3 dB Bandwidth G = 1 800 800 800 kHz G = 10 100 100 100 kHz G = 100 10 10 10 kHz G = 1000 2 2 2 kHz Slew Rate 0.3 0.3 0.3 V/µs Settling Time to 0.01% VS = ±5 V, 5 V step G = 1 30 30 30 µs G = 10 20 20 20 µs 1 Does not include effects of external resistor, RG. 2 One input grounded. G = 1.

Rev. G | Page 8 of 32 SPECIFICATIONS COMMON TO DUAL AND SINGLE SUPPLIES Table 4. Test Conditions/ Comments AD623ANZ, AD623ARZ AD623ARM AD623BNZ, AD623BRZ Parameter Min Typ Max Min Typ Max Min Typ Max Unit NOISE Voltage Noise, 1 kHz Total RTI noise = √((eNI)2 + (2eNO/G)2) Input, Voltage Noise, eni 35 35 35 nV/√Hz Output, Voltage Noise, eno 50 50 50 nV/√Hz RTI, 0.1 Hz to 10 Hz G = 1 3.0 3.0 3.0 µV p-p G = 1000 1.5 1.5 1.5 µV p-p Current Noise f = 1 kHz 100 100 100 fA/√Hz 0.1 Hz to 10 Hz 2.5 2.5 2.5 pA p-p REFERENCE INPUT Input Resistance, RIN 100 ± 20% 100 ± 20% 100 ± 20% kΩ Input Current, IIN Input voltage (V+IN) = 0 V, reference voltage (VREF) = 0 V 50 60 50 60 50 60 µA Voltage Range −VS +VS −VS +VS −VS +VS V Gain to Output 1 ± 0.0002 1 ± 0.0002 1 ± 0.0002 V/V POWER SUPPLY Operating Range Dual supply ±2.5 ±6 ±2.5 ±6 ±2.5 ±6 V Single supply 2.7 12 2.7 12 2.7 12 V Quiescent Current Dual supply 375 550 375 550 375 550 µA Single supply 305 480 305 480 305 480 µA Over Temperature 625 625 625 µA TEMPERATURE RANGE For Specified Performance −40 +85 −40 +85 −40 +85 °C

Rev. G | Page 9 of 32 ABSOLUTE MAXIMUM RATINGS Table 5. Parameter Rating Supply Voltage 12 V Internal Power Dissipation1 650 mW Differential Input Voltage ±6 V Output Short-Circuit Duration Indefinite Storage Temperature Range −65°C to +125°C Operating Temperature Range −40°C to +85°C Lead Temperature (Soldering, 10 sec) 300°C

1 Specification is for device in free air:

8-Lead PDIP Package: θJA = 95°C/W 8-Lead SOIC Package: θJA = 155°C/W 8-Lead MSOP Package: θJA = 200°C/W Stresses at or above those listed under Absolute Maximum Ratings may cause permanent damage to the product. This is a stress rating only; functional operation of the product at these or any other conditions above those indicated in the operational section of this specification is not implied. Operation beyond the maximum operating conditions for extended periods may affect product reliability. ESD CAUTION

Figure 2. Pin Configuration Table 6. Pin Function Descriptions 1 −RG Inverting Terminal of External Gain Setting Resistor, RG. 2 −IN Inverting In-Amp Input. 3 +IN Noninverting In-Amp Input. 4 −VS Negative Supply Terminal. 5 REF In-Amp Output Reference Input. The voltage input establishes the common-mode voltage of the output. 7 +VS Positive Supply Terminal. 8 +RG Noninverting Terminal of External Gain Setting Resistor, RG.

AD623 a versatile instrumentation amplifier. common-mode signal at the output of the input amplifiers. enhanced (see Figure 30, Figure 31, Figure 32, and Figure 33). (OUTPUT) is all that is needed. Figure 70. Simplified Schematic

film capacitors are recommended. optimal CMR over frequency, the shield must be properly driven. capacitance mismatch between the inputs. Figure 75. Common-Mode Shield Driver minimize interference between the digital and analog circuitry. to route current to both digital and analog circuitry.

4 VIN1

3 VIN2

Figure 76. Optimal Grounding Practice for a Bipolar Supply Environment with Separate Analog and Digital Supplies Figure 77. Optimal Ground Practice in a Single-Supply Environment

proportional with the input offset voltage of the amplifier. Figure 78. Ground Returns for Bias Currents with Transformer-Coupled Figure 79. Ground Returns for Bias Currents with Thermocouple Inputs Figure 80. Ground Returns for Bias Currents with AC-Coupled Inputs summarizes the performance of some buffer op amps. Figure 81. Output Buffering Table 9. Buffering Options

0.1 V below ground, it is possible to measure small differential

Figure 82. Amplifying Bipolar Signals with Low Common-Mode Voltage couple delivers a voltage ranging from −7.890 mV to +10.777 m V. from 1.110 V to 3.077 V relative to ground.

Table 10. Maximum Attainable Gain and Resulting Output Swing for Different Input Conditions For an updated design of the AD623, see the AD8223. Analog Devices website at www.analog.com/inamps.

0.65 BSC

1.10 MAX

Figure 87. 8-Lead Mini Small Outline Package [MSOP] registered trademarks are the property of their respective owners.