Low Drift, Low Power a Instrumentation Amplifier AD621 CONNECTION DIAGRAM FEATURES 8-Lead Plastic Mini-DIP (N), Cerdip (Q) EASY TO USE and SOIC (R) Packages Pin-Strappable Gains of 10 and 100 All Errors Specified for Total System Performance Higher Performance than Discrete In Amp Designs 1 8 G = 10/100 G = 10/100 Available in 8-Lead DIP and SOIC IN 2 7 +V AD621 S Low Power, 1.3 mA Max Supply Current TOP VIEW +IN 3 6 OUTPUT Wide Power Supply Range ( 2.3 V to 18 V) (Not to Scale) V 4 5 REF S EXCELLENT DC PERFORMANCE 0.15% Max, Total Gain Error 5 ppm/ C, Total Gain Drift gain drift errors are achieved by the use of internal gain setting 125 V Max, Total Offset Voltage resistors. Fixed gains of 10 and 100 can easily be set via external 1.0 V/ C Max, Offset Voltage Drift pin strapping. The AD621 is fully specified as a total system, therefore, simplifying the design process. LOW NOISE 9 nV/Hz, 1 kHz, Input Voltage Noise For portable or remote applications, where power dissipation, 0.28 V p-p Noise (0.1 Hz to 10 Hz) size, and weight are critical, the AD621 features a very low supply current of 1.3 mA max and is packaged in a compact EXCELLENT AC SPECIFICATIONS 8-lead SOIC, 8-lead plastic DIP or 8-lead cerdip. The AD621 800 kHz Bandwidth (G = 10), 200 kHz (G = 100) also excels in applications requiring high total accuracy, such 12 s Settling Time to 0.01% as precision data acquisition systems used in weigh scales and APPLICATIONS transducer interface circuits. Low maximum error specifications Weigh Scales including nonlinearity of 10 ppm, gain drift of 5 ppm/C, 50 V Transducer Interface and Data Acquisition Systems offset voltage, and 0.6 V/C offset drift (B grade), make Industrial Process Controls possible total system performance at a lower cost than has been Battery-Powered and Portable Equipment previously achieved with discrete designs or with other mono- PRODUCT DESCRIPTION lithic instrumentation amplifiers. The AD621 is an easy to use, low cost, low power, high accu- When operating from high source impedances, as in ECG and racy instrumentation amplifier that is ideally suited for a wide blood pressure monitors, the AD621 features the ideal combina- range of applications. Its unique combination of high perfor- tion of low noise and low input bias currents. Voltage noise is mance, small size and low power, outperforms discrete in amp specified as 9 nV/Hz at 1 kHz and 0.28 V p-p from 0.1 Hz to implementations. High functionality, low gain errors, and low 10 Hz. Input current noise is also extremely low at 0.1 pA/Hz. 30,000 The AD621 outperforms FET input devices with an input bias current specification of 1.5 nA max over the full industrial tem- perature range. 25,000 3 OP AMP 10,000 IN AMP 20,000 (3 OP 07S) 1,000 15,000 TYPICAL STANDARD BIPOLAR INPUT 10,000 AD621A 100 IN AMP 5,000 10 AD621 SUPER ETA BIPOLAR INPUT 0 025 10 150 IN AMP 1 SUPPLY CURRENT mA Figure 1. Three Op Amp IA Designs vs. AD621 0.1 1k 10k 100k 1M 10M 100M SOURCE RESISTANCE REV. B Figure 2. Total Voltage Noise vs. Source Resistance 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 One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. which may result from its use. No license is granted by implication or Tel: 781/329-4700 World Wide Web Site: AD621SPECIFICATIONS (Typical 25 C, V = 15 V, and R = 2 k , unless otherwise noted.) Gain = 10 S L 1 AD621A AD621B AD621S Model Conditions Min Typ Max Min Typ Max Min Typ Max Unit GAIN = 10 V 0.15 0.05 0.15 % Gain Error V OUT Nonlinearity, V = 10 V to +10 V R = 2 k 2 10 2 10 2 10 ppm of FS OUT L Gain vs. Temperature 1.5 5 1.5 51 5 ppm/C TOTAL VOLTAGE OFFSET Offset (RTI) V = 15 V 75 250 50 125 75 250 V S Over Temperature V = 5 V to 15 V 400 215 500 V S Average TC V = 5 V to 15 V 1.0 2.5 0.6 1.5 1.0 2.5 V/C S Offset Referred to the 2 Input vs. Supply (PSR) V = 2.3 V to 18 V 95 120 100 120 95 120 dB S Total NOISE Voltage Noise (RTI) 1 kHz 13 17 13 17 13 17 nV/Hz RTI 0.1 Hz to 10 Hz 0.55 0.55 0.8 0.55 0.8 V p-p Current Noise f = 1 kHz 100 100 100 fA/Hz 0.1 Hz10 Hz 10 10 10 pA p-p = 15 V INPUT CURRENT V S Input Bias Current 0.5 2.0 0.5 1.0 0.5 2 nA Over Temperature 2.5 1.5 4 nA Average TC 3.0 3.0 8.0 pA/C Input Offset Current 0.3 1.0 0.3 0.5 0.3 1.0 nA Over Temperature 1.5 0.75 2.0 nA Average TC 1.5 1.5 8.0 pA/C INPUT Input Impedance Differential 10 210 210 2G pF Common-Mode 10 210 210 2G pF 3 Input Voltage Range V = 2.3 V to 5 V V + 1.9 +V 1.2 V + 1.9 +V 1.2 V + 1.9 +V 1.2 V S S S S S S S Over Temperature V + 2.1 +V 1.3 V + 2.1 +V 1.3 V + 2.1 +V 1.3 V S S S S S S V = 5 V to 18 V V + 1.9 +V 1.4 V + 1.9 +V 1.4 V + 1.9 +V 1.4 V S S S S S S S Over Temperature V + 2.1 +V 1.4 V + 2.1 +V 1.4 V + 2.3 +V 1.4 V S S S S S S Common-Mode Rejection Ratio DC to 60 Hz with 1 k Source Imbalance V = 0 V to 10 V 93 110 100 110 93 110 dB CM OUTPUT Output Swing R = 10 k , L V = 2.3 V to 5 V V + 1.1 +V 1.2 V + 1.1 +V 1.2 V + 1.1 +V 1.2 V S S S S S S S Over Temperature V + 1.4 +V 1.3 V + 1.4 +V 1.3 V + 1.6 +V 1.3 V S S S S S S V = 5 V to 18 V V + 1.2 +V 1.4 V + 1.2 +V 1.4 V + 1.2 +V 1.4 V S S S S S S S Over Temperature V + 1.6 +V 1.5 V + 1.6 +V 1.5 V + 2.3 +V 1.5 V S S S S S S Short Current Circuit 18 18 18 mA DYNAMIC RESPONSE Small Signal, 3 dB Bandwidth 800 800 800 kHz Slew Rate 0.75 1.2 0.75 1.2 0.75 1.2 V/ s Settling Time to 0.01% 10 V Step 12 12 12 s REFERENCE INPUT R 20 20 20 k IN I V +, V = 0 50 60 50 60 +50 +60 A IN IN REF Voltage Range V + 1.6 +V 1.6 V + 1.6 +V 1.6 V + 1.6 +V 1.6 V S S S S S S Gain to Output 1 0.0001 1 0.0001 1 0.0001 POWER SUPPLY Operating Range 2.3 18 2.3 18 2.3 18 V Quiescent Current V = 2.3 V to 18 V 0.9 1.3 0.9 1.3 0.9 1.3 mA S Over Temperature 1.1 1.6 1.1 1.6 1.1 1.6 mA TEMPERATURE RANGE For Specified Performance 40 to +85 40 to +85 55 to +125 C NOTES 1 See Analog Devices military data sheet for 883B tested specifications. 2 This is defined as the supply range over which PSRR is defined. 3 Input Voltage Range = CMV + (Gain V ). DIFF Specifications subject to change without notice. 2 REV. B