Using Digital Potentiometers For Programmable Amplifier Gain

By Microchip Technology Inc.

Usually a sensor requires its output signal to be amplified before being converted to a digital representation. Many times an operational amplifier (op amp) is used to implement a signal gain circuit. The programmability of this type of circuit allows the following issues to be solved:

• Optimization of the sensor output voltage range
• Calibration of the amplifier circuit’s gain
• Adapting gain to input signal variations
  • sensor characteristics change over temperature/voltage
  • multiple input sources into a single gain circuit
• Field calibration updates
• Increased reliability vs mechanical potentiometer
• BOM consolidation – one op amp and one digital potentiometer supporting the various sensor options