ST STM32G474 User Manual (English)

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RM0440 Rev 4 791/2126

RM0440 Operational amplifiers (OPAMP)

829

Programmable gain amplifier mode

The procedure to use the OPAMP as programmable gain amplifier is presented hereafter.

• configure VM_SEL bits as “Feedback resistor is connected to OPAMPx_VINM input”,

• configure PGA_GAIN bits as “internal Gain 2, 4, 8, 16,32, or 64”, 00000 to 00101

• configure VP_SEL bits as “GPIO connected to OPAMPx_VINP”, 00

As soon as the OPAEN bit is set, the voltage on pin OPAMPx_VINP is amplified by the

selected gain and visible on pin OPAMPx_VOUT.

Note: To avoid saturation, the input voltage must stay below V

DDA

divided by the selected gain.

Figure 173. PGA mode, internal gain setting (x2/x4/x8/x16/x32/x64),

inverting input not used

STM32

VINM0

VINM1

MSv48041V1

VOUT

VINP3 or DACx_CHy

VINP2

VINP1

VINP0

1. opamp_out can be redirected internally to an ADC channel by setting OPAINTOEN bit.

In this case, the I/O on which is mapped the OPAMPx_VOUT is free and can be used for another purpose.

opamp_out

(1)

ST STM32G474 User Manual