Programmable gain without the resistor network
The Microchip MCP6S91T-E/SN is a single-channel programmable gain amplifier (PGA) that replaces the traditional op-amp plus external resistor-ladder gain-setting circuit. It integrates an SPI-programmable gain stage with eight selectable gain settings, eliminating the need for precision feedback resistors and reducing board area. Input bias current is 1 pA typical, which minimizes offset errors when driving high-impedance sensors such as photodiodes or pH probes.
Supply current and output drive
Input offset voltage is 400 µV maximum, a figure that matters when the PGA is set to high gain because the offset is multiplied by the gain setting.
For a design that relies on programmable gain in a single 8-SOIC footprint, this part is a stable BOM line without forced-migration risk.