Low Cost, Low Power Instrumentation Amplifier AD620 CONNECTION DIAGRAM
FEATURES EASY TO USE Gain Set with One External Resistor (Gain Range 1 to 1000} Wide Power Supply Range (؎2.3 V to ؎18 V) Higher Performance than Three Op Amp IA Designs Available in 8-Pin DIP and SOIC Packaging Low Power, 1.3 mA max Supply Current
8-Pin Plastic Mini-DIP (N), Cerdip (Q) and SOIC (R) Packages
LOW NOISE 9 nV/√Hz, @ 1 kHz, Input Voltage Noise 0.28 V p Noise (0.1 Hz to 10 Hz)
The AD620, with its high accuracy of 40 ppm maximum nonlinearity, low offset voltage of 50 µV max and offset drift of 0.6 µV/°C max, is ideal for use in precision data acquisition systems, such as weigh scales and transducer interfaces. Furthermore, the low noise, low input bias current, and low power of the AD620 make it well suited for medical applications such as ECG and noninvasive blood pressure monitors.
APPLICATIONS Weigh Scales ECG and Medical Instrumentation Transducer Interface Data Acquisition Systems Industrial Process Controls Battery Powered and Portable Equipment PRODUCT DESCRIPTION
The AD620 is a low cost, high accuracy instrumentation amplifier which requires only one external resistor to set gains of 1 to 1000. Furthermore, the AD620 features 8-pin SOIC and DIP packaging that is smaller than discrete designs, and offers lower 30,000
The low input bias current of 1.0 nA max is made possible with the use of Superβeta processing in the input stage. The AD620 works well as a preamplifier due to its low input voltage noise of 9 nV/√Hz at 1 kHz, 0.28 µV p in the 0.1 Hz to 10 Hz band, 0.1 pA/√Hz input current noise. Also, the AD620 is well suited for multiplexed applications with its settling time of 15 µs to 0.01% and its cost is low enough to enable designs with one in amp per channel. 10,000
3 OP-AMP IN-AMP (3 OP-07s)
RTI VOLTAGE NOISE (0.1 –10Hz) – µV p
TOTAL ERROR, PPM OF FULL SCALE
power (only 1.3 mA max supply current), making it a good fit for battery powered, portable (or remote) applications.
EXCELLENT AC SPECIFICATIONS 120 kHz Bandwidth (G = 100) 15 s Settling Time to 0.01%
AD620A 10,000 RG
TYPICAL STANDARD BIPOLAR INPUT IN-AMP
10 G = 100
AD620 SUPERßETA BIPOLAR INPUT IN-AMP
EXCELLENT DC PERFORMANCE (“A GRADE”) 125 V max, Input Offset Voltage (50 V max “B” Grade) 1 V/؇C max, Input Offset Drift 2.0 nA max, Input Bias Current 93 dB min Common-Mode Rejection Ratio (G = 10)
SUPPLY CURRENT – mA
SOURCE RESISTANCE – Ω
Three Op Amp IA Designs vs. AD620
Total Voltage Noise vs. Source Resistance
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