Datasheet AD620 (Analog Devices)

Low Cost Low Power Instrumentation Amplifier AD620 FEATURES CONNECTION DIAGRAM Easy to use Gain set with one external resistor R 1 8 G RG (Gain range 1 to 10,000) –IN 2 7 +V Wide power supply range (±2.3 V to ±18 V) S Higher performance than 3 op amp IA designs +IN 3 6 OUTPUT Available in 8-lead DIP and SOIC packaging –VS 4 5 REF AD620 Low power, 1.3 mA max supply current TOP VIEW
00775-0-001
Excellent dc performance (B grade) 50 μV max, input offset voltage
Figure 1. 8-Lead PDIP (N), CERDIP (Q), and SOIC (R) Packages
0.6 μV/°C max, input offset drift PRODUCT DESCRIPTION 1.0 nA max, input bias current
The AD620 is a low cost, high accuracy instrumentation
100 dB min common-mode rejection ratio (G = 10)
amplifier that requires only one external resistor to set gains of
Low noise
1 to 10,000. Furthermore, the AD620 features 8-lead SOIC and
9 nV/√Hz @ 1 kHz, input voltage noise
DIP packaging that is smaller than discrete designs and offers
0.28 μV p-p noise (0.1 Hz to 10 Hz)
lower power (only 1.3 mA max supply current), making it a
Excellent ac specifications
good fit for battery-powered, portable (or remote) applications.
120 kHz bandwidth (G = 100) 15 μs settling time to 0.01%
The AD620, with its high accuracy of 40 ppm maximum nonlinearity, low offset voltage of 50 μV max, and offset drift of
APPLICATIONS
0.6 μV/°C max, is ideal for use in precision data acquisition
Weigh scales
systems, such as weigh scales and transducer interfaces.
ECG and medical instrumentation
Furthermore, the low noise, low input bias current, and low power
Transducer interface
of the AD620 make it well suited for medical applications, such
Data acquisition systems
as ECG and noninvasive blood pressure monitors.
Industrial process controls
The low input bias current of 1.0 nA max is made possible with
Battery-powered and portable equipment
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-p in the 0.1 Hz to 10 Hz band, and 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.
Table 1. Next Generation Upgrades for AD620 30,000 Part Comment 25,000 3 OP AMP
AD8221 Better specs at lower price
IN-AMP (3 OP-07s)
AD8222 Dual channel or differential out
20,000 FULL SCALE
AD8226 Low power, wide input range
F O 15,000
AD8220 JFET input
R, PPM AD620A
AD8228 Best gain accuracy
10,000 R
AD8295 +2 precision op amps or differential out
G TAL ERRO
AD8429 Ultra low noise
5,000 TO 0 0 5 10 15 20 SUPPLY CURRENT (mA)
00775-0-002 Figure 2. Three Op Amp IA Designs vs. AD620
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Document Outline SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ESD CAUTION TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION Make vs. Buy: a Typical Bridge Application Error Budget Pressure Measurement Medical ECG Precision V-I Converter GAIN SELECTION INPUT AND OUTPUT OFFSET VOLTAGE REFERENCE TERMINAL INPUT PROTECTION RF INTERFERENCE COMMON-MODE REJECTION GROUNDING GROUND RETURNS FOR INPUT BIAS CURRENTS AD620ACHIPS INFORMATION OUTLINE DIMENSIONS ORDERING GUIDE