5.4.5 Operational Amplifiers (Op Amp)

Some PIC16F, PIC18F and PIC32CM MCUs have integrated Operational Amplifier (Op Amp) peripherals designed for flexible, low-power analog signal conditioning. The op amp peripherals provide up to three individually configurable op amps with rail-to-rail inputs, internal resistor ladders for feedback and gain control, and a wide range of selectable configurations. The PIC16F, PIC18F and PIC32CM op amps enable complex analog signal processing with minimal or no external components. Table 5-18 provides a comparison of features between PIC16F, PIC18F and PIC32CM.

Table 5-18. PIC16F, PIC18F and PIC32CM OPAMP Features
Feature/AspectPIC16F OPAPIC18F OPAPIC32CM OPAMP
Number of Op AmpsUp to fourUp to twoUp to three
Input Selection

I/O pins, DAC

Basic OPA: FVR

Enhanced OPA: internal resistor ladder

I/O pins, DAC

Internal resistor ladder

I/O pins, DAC, ground

Other op amps

Internal resistor ladder

Output SelectionI/O pinI/O pins, ADC, ACI/O pins, ADC, AC

Other op amps

Internal Resistor LadderConfigurable for internal feedback/programmable gainConfigurable for internal feedback/programmable gainConfigurable for internal feedback/programmable gain
Configurations

Stand-alone

Unity gain buffer

Inverting/non-inverting PGA

Comparator

Stand-alone

Unity gain buffer

Inverting/non-inverting PGA

Comparator

Stand-alone

Unity gain buffer

Inverting/non-inverting PGA

Cascaded PGAs

Instrumentation amplifier

Comparator with hysteresis

CalibrationAutomatic input or adjustable input offset voltage calibrationAutomatic input or adjustable input offset voltage calibrationOffset/gain measurement with ADC
Power ModesStandardStandardFour selectable modes (speed vs. power), on-demand start-up
Event System IntegrationN/AN/AOn-demand start-up for ADC/AC
Special Features—Built-in hardware peak detect

Voltage doubler

Programmable hysteresis

Low Power OperationSupported Supported Supported
Output to PinSupported Supported Supported