Based on the footprint of our popular thermocouple amplifier, Herdware is proud to present an Instrumentation amplifier in that same format.

FEATURES

Resistor programmable gain range: 101 to 1000
Supply voltage range: ±4 V to ±8 V
Rail-to-rail input and output
Maintains performance over −40°C to +125°C
Excellent ac and dc performance
110 dB minimum CMR @ 60 Hz, G = 10 to 1000
10 μV maximum offset voltage (RTI, ±5 V operation)
50 nV/°C maximum offset drift
20 ppm maximum gain nonlinearity
Load Cell Amplifier
Raw Thermocouple Amplifier

APPLICATIONS

Pressure measurements
Temperature measurements
Strain measurements
Automotive diagnostics

GENERAL DESCRIPTION

The AD8230 is a low drift, differential sampling, precision instrumentation amplifier. Auto-zeroing reduces offset voltage drift to less than 50 nV/°C.

The AD8230 is well-suited for thermocouple and bridge transducer applications. The AD8230’s high CMR of 110 dB (minimum) rejects line noise in measurements where the sensor is far from the instrumentation.

The 16 V rail-to-rail, common-mode input range is useful for noisy environments where ground potentials vary by several volts. Low frequency noise is kept to a minimal 3 μV p-p, making the AD8230 perfect for applications requiring the utmost dc precision. Moreover, the AD8230 maintains its high performance over the extended industrial temperature range of −40°C to +125°C.

Two external resistors are used to program the gain. By using matched external resistors, the gain stability of the AD8230 is much higher than instrumentation amplifiers that use a single resistor to set the gain. In addition to allowing users to program the gain between 101 and 1000, users can adjust the output offset voltage.

Gain resistors may be soldered directly to the board, inserted into high quality machine terminals, or turret terminals.

Instrumentation Amplifier schematic

Instrumentation Amplifier Wiring Diagram Instrumentation Amp Wiring Rev0

AD8230 Data Sheet

AD8230 Gain Setting Resistors

THEORY OF OPERATION

Auto-zeroing is a dynamic offset and drift cancellation
technique that reduces input-referred voltage offset to the
μV level and voltage offset drift to the nV/°C level.

A further advantage of dynamic offset cancellation is the reduction of
low frequency noise, in particular the 1/f component.

The AD8230 is an instrumentation amplifier that uses an
auto-zeroing topology and combines it with high commonmode signal rejection.

The internal signal path consists of an active differential sample-and-hold stage (preamp) followed by a differential amplifier (gain amp). Both amplifiers implement auto-zeroing to minimize offset and drift. A fully differential topology increases the immunity of the signals to parasitic noise and temperature effects.

Amplifier gain is set by two external resistors for convenient TC matching.