Programmable gain amplifier
A programmable gain amplifier (PGA) (in German: amplifier with programmable gain) consists of an operational amplifier that is wired as a non-inverted amplifier (electrometer). Depending on the type and manufacturer, the feedback can be changed by connecting individual pins (parallel), the SPI or I²C bus (serial) and thus the gain can be adjusted. In some cases, a programmable analog multiplexer is also installed, which can be used to switch between the various input channels.
application
PGAs are mainly used in measurement technology to improve the sensitivity of a measurement with ADC (which can only process signals discretely and depending on their operating voltage). The possibility of using an internal multiplexer has the advantage that only a few pins of the controlling element ( microcontroller ) have to be used.