Category: Amplifiers CIRCUIT IDEAS FOR DESIGNERS Schematic no. amp_27006.0 Low Voltage Instrumentation Amplifier Description This circuit presents a low voltage instrumentation amplifier operating on +/-1V power supplies. This circuit is designed to amplify low level difference-mode signals over a common mode voltage range that may be relatively large compared to the signal voltage levels. Many transducer and bridge circuits that generate limited output voltages can be buffered and amplifier by using this low voltage instrumentation amplifier. In this amplifier, the circuit functions as a difference amplifier with high input impedance with respect to the input signals. The 1Mohm input resistances provide isolation and over-voltage protection between the input signal and the instrumentation amplifier. The output impedance for this instrumentation amplifier is very low. The gain of the first stage is given by (1+100K/50K) and the gain for the second stage is equal to (500K/100K). For a differential input VIN, the output is given by VOUT = VIN x (500K/100K) x (1+100K/50K). In this example, the gain is fixed at 15 Recommended Components ALD1706, ALD1701, ALD1721, ALD2701, ALD2706, ALD2711 Precision versions: ALD1726, ALD2711A, ALD2721 Other Related Circuit Ideas Schematic no. amp_27002.0 Low Voltage High Input Impedance Precision DC Summing Amplifier Schematic no. amp_27003.0 High Input Impedance Precision DC Summing Amplifier 2005 Advanced Linear Devices, Inc. Information furnished by Advanced Linear Devices, Inc. (ALD) is believed to be accurate and reliable. However, ALD assumes no responsibility for the use of such information nor for any infringement of patent or rights of third parties that may result from its use. No license is granted implication or otherwise under any patent rights of ALD. www.aldinc.com