Operational Amplifier (Opamp); Opamp Introduction; Opamp Main Features; Opamp Functional Description - STMicroelectronics RM0365 Reference Manual

Operational amplifier (OPAMP)

18 Operational amplifier (OPAMP)
18.1

OPAMP introduction

STM32F302xB/C/D/E devices embed 2 operational amplifiers OPAMP1, OPAMP2 and
STM32F302x6/8 devices embed 1 operational amplifier OPAMP2. They can either be used
as standalone amplifiers or as follower / programmable gain amplifiers.
The operational amplifier output is internally connected to an ADC channel for measurement
purposes.
18.2

OPAMP main features

•
Rail-to-rail input/output
•
Low offset voltage
•
Capability of being configured as a standalone operational amplifier or as a
programmable gain amplifier (PGA)
•
Access to all terminals
•
Input multiplexer on inverting and non-inverting input
•
Input multiplexer can be triggered by a timer and synchronized with a PWM signal.
18.3

OPAMP functional description

18.3.1

General description

On every OPAMP, there is one 4:1 multiplexer on the non-inverting input and one 2:1
multiplexer on the inverting input.
The inverting and non inverting inputs selection is made using the VM_SEL and VP_SEL
bits respectively in the OPAMPx_CSR register.
The I/Os used as OPAMP input/outputs must be configured in analog mode in the GPIOs
registers.
The connections with dedicated I/O are summarized in the table below and in
and Figure
OPAMP1 inverting
PA3 (VM1)
PC5 (VM0)
PA5 (VP3)
1. Only in STM32F302xB/C/D/E devices.
423/1080
121.

Table 105. Connections with dedicated I/O

OPAMP1 non
(1)
input inverting input
-
OPAMP2 inverting
(1)
PA1 (VP0)
PA7 (VP1)
PA3 (VP2)
-
DocID025202 Rev 7
OPAMP2 non
input inverting input
PA5 (VM1)
PC5 (VM0)
-
- PB14 (VP3)
RM0365
Figure 120
PA7 (VP0)
PD14 (VP1)
PB0 (VP2)
(1)