Datasheet AD621 (Analog Devices)

a
Low Drift, Low Power Instrumentation Amplifier AD621 FEATURES CONNECTION DIAGRAM EASY TO USE 8-Lead Plastic Mini-DIP (N), Cerdip (Q) Pin-Strappable Gains of 10 and 100 and SOIC (R) Packages 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 AD621 +VS Low Power, 1.3 mA Max Supply Current TOP VIEW +IN 3 6 OUTPUT Wide Power Supply Range (
ⴞ
2.3 V to
ⴞ
18 V) (Not to Scale) –V 4 5 REF S EXCELLENT DC PERFORMANCE 0.15% Max, Total Gain Error
ⴞ
5 ppm/
ⴗ
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/
ⴗ
C Max, Offset Voltage Drift
pin strapping. The AD621 is fully specified as a total system,
LOW NOISE
therefore, simplifying the design process.
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
EXCELLENT AC SPECIFICATIONS
supply current of 1.3 mA max and is packaged in a compact
800 kHz Bandwidth (G = 10), 200 kHz (G = 100)
8-lead SOIC, 8-lead plastic DIP or 8-lead cerdip. The AD621
12
␮
s Settling Time to 0.01%
also excels in applications requiring high total accuracy, such 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 µV
Transducer Interface and Data Acquisition Systems
offset voltage, and 0.6 µV/°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 µV 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-
25,000
perature range.
3 OP AMP 10,000 IN AMP 20,000 (3 OP 07S) Vp-p
␮
– 1,000 15,000 ppm OF FULL SCALE TYPICAL STANDARD OR, BIPOLAR INPUT 10,000 AD621A 100 IN AMP L ERR 10Hz) A T – O 5,000 T (0.1 10 AD621 SUPER
␤
ETA 0 BIPOLAR INPUT 0 5 10 15 20 IN AMP 1 SUPPLY CURRENT – mA
Figure 1. Three Op Amp IA Designs vs. AD621
TOTAL INPUT VOLTAGE NOISE, G = 100 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
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