Opamp Modes; Figure 122. Timer Controlled Multiplexer Mode - STMicroelectronics RM0365 Reference Manual

Operational amplifier (OPAMP)
VMS_SEL bit fields in the OPAMP control register. If the TCM_EN bit is cleared, the
selection is done using the VP_SEL and VM_SEL bit fields in the OPAMP control register.
18.3.7

OPAMP modes

The operational amplifier inputs and outputs are all accessible on terminals. The amplifiers
can be used in multiple configuration environments:
•
Standalone mode (external gain setting mode)
• Follower configuration mode
•
PGA modes
Important note: the amplifier output pin is directly connected to the output pad to minimize
the output impedance. It cannot be used as a general purpose I/O, even if the amplifier is
configured as a PGA and only connected to the ADC channel.
Note: The impedance of the signal must be maintained below a level which avoids the input
leakage to create significant artefacts (due to a resistive drop in the source). Please refer to
the electrical characteristics section in the datasheet for further details.
Standalone mode (external gain setting mode)
The external gain setting mode gives full flexibility to choose the amplifier configuration and
feedback networks. This mode is enabled by writing the VM_SEL bits in the OPAMPx_CR
register to 00 or 01, to connect the inverting inputs to one of the two possible I/Os.
427/1080

Figure 122. Timer controlled Multiplexer mode

DocID025202 Rev 7
RM0365