AMP01:  Low Noise, Precision Instrumentation Amplifier

The AMP01 is a monolithic instrumentation amplifier designed for high-precision data acquisition and instrumentation applications. The design combines the conventional features of an instrumentation amplifier with a high current output stage. The output remains stable with high capacitance loads (1 µF), a unique ability for an instrumentation amplifier. Consequently, the AMP01 can amplify low level signals for transmission through long cables without requiring an output buffer. The output stage may be configured as a voltage or current generator.

Input offset voltage is very low (20 µV) which generally eliminates the external null potentiometer. Temperature changes have minimal effect on offset; TCV_IOS is typically 0.15 µV/°C. Excellent low-frequency noise performance is achieved with a minimal compromise on input protection. Bias current is very low, less than 10 nA over the military temperature range. High common-mode rejection of 130 dB, 16-bit linearity at a gain of 1000, and 50 mA peak output current are achievable simultaneously. This combination takes the instrumentation amplifier one step further towards the ideal amplifier.

AC performance complements the superb dc specifications. The AMP01 slews at 4.5 V/µs into capacitive loads of up to 15 nF, settles in 50 µs to 0.01% at a gain of 1000, and boasts a healthy 26 MHz gain-bandwidth product. These features make the AMP01 ideal for high speed data-acquisition systems.

Gain is set by the ratio of two external resistors over a range of 0.1 to 10,000. A very low gain-temperature-coefficient of 10 ppm/°C is achievable over the whole gain range. Output voltage swing is guaranteed with three load resistances; 50 Ohm, 500 Ohm, and 2 kOhm. Loaded with 500 Ohm, the output delivers ±13.0 V minimum. A thermal shutdown circuit prevents destruction of the output transistors during overload conditions.

The AMP01 can also be configured as a high performance operational amplifier. In many applications, the AMP01 can be used in place of op amp/power-buffer combinations.