Unlike a discrete operational amplifier, the latest OPA module has unique
features and integrations that reduce board space, the number of external components
required, and allows for easy configuration. The module is configurable in software,
which allows the designer to change gain settings, amplifier configurations, or to
disable the module without using any external components.
Figure 3-1 shows the block diagram
of the OPA module. The key components of this module are:
Operational amplifier, which uses
OPAxIN+ and OPAxIN- as inputs.
Feedback control multiplexer
(FMS), which selects the internal feedback path from the options of
VDD, OPAxOUT or No Connection.
Unity gain multiplexer (UG),
which is used to enable unity gain on the device.
Channel input multiplexers (NCH
and PCH), which selects which signal is connected to the operational amplifier’s
inputs.
Resistor ladder (GSEL and RESON),
which provides the programmable gain options for the operational amplifier.
Input source multiplexers (NSS
and PSS), which select the I/O pins that are inputs to the module.
Figure 3-1. PIC18-Q41 OPA Module Block
Diagram
Note:
Refer to the “Pin
Allocation Table” section of the device data sheet for details about
OPAxIN- and OPAxIN+ availability per port.
