35.2 Overview

The Analog Signal Conditioning (OPAMP) peripheral features three operational amplifiers (op amps), designated OPn where n is zero, one or two. These op amps are implemented with a flexible connection scheme using analog multiplexers and resistor ladders, which allows a large number of analog signal conditioning configurations to be achieved, many of which require no external components. A multiplexer at the non-inverting (+) input of each op amp allows connection to either an external pin, a wiper position from a resistor ladder, a DAC output, ground, V_DD/2, or an output from another op amp. A second multiplexer at the inverting (-) input of each op amp allows connection to either an external pin, a wiper position from a resistor ladder, the output of the op amp, or DAC output. Three more multiplexers connected to each resistor ladder provide additional configuration flexibility. Two of these multiplexers select the top and bottom connections to the resistor ladder, and the third controls the wiper position.