AMP02 Analog Devices, AMP02 Datasheet - Page 10

• Manufacturer Part Number: AMP02
• Description: High Accuracy 8-Pin Instrumentation Amplifier
• Manufacturer: Analog Devices

OVERVOLTAGE PROTECTION
Instrumentation amplifiers invariably sit at the front end of in-
strumentation systems where there is a high probability of expo-
sure to overloads. Voltage transients, failure of a transducer, or
removal of the amplifier power supply while the signal source is
connected may destroy or degrade the performance of an unpro-
tected device. A common technique used is to place limiting re-
sistors in series with each input, but this adds noise. The
AMP02 includes internal protection circuitry that limits the in-
put current to 4 mA for a 60 V differential overload (see Figure
28) with power off, 2.5 mA with power on.
Figure 28. AMP02’s Input Protection Circuitry Limits Input
Current During Overvoltage Conditions
AMP02
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POWER SUPPLY CONSIDERATIONS
Achieving the rated performance of precision amplifiers in a
practical circuit requires careful attention to external influences.
For example, supply noise and changes in the nominal voltage
directly affect the input offset voltage. A PSR of 80 dB means
that a change of 100 mV on the supply, not an uncommon
value, will produce a 10 V input offset change. Consequently,
care should be taken in choosing a power unit that has a low
output noise level, good line and load regulation, and good tem-
perature stability. In addition, each power supply should be
properly bypassed.
REV. D