RM0440 Rev 4 793/2126
RM0440 Operational amplifiers (OPAMP)
829
Programmable gain amplifier, non-inverting with external bias
or inverting mode
The procedure to use the OPAMP to amplify the amplitude of an input signal with bias
voltage for non-inverting mode or inverting mode.
• configure VM_SEL bits as “Feedback resistor is connected to OPAMPx_VINM input”,
10
• configure PGA_GAIN bits as “Inverting gain = -1, -3, -7, -15, -31, -63 / Non-inverting
gain =2, 4, 8, 16, 32, 64 with VINM0”, 01000 to 01101
• configure VP_SEL bits as “GPIO connected to OPAMPx_VINP”.
Figure 175. PGA mode, non-inverting gain setting (x2/x4/x8/x16/x32/x64)
or inverting gain setting (x-1/x-3/x-7/x-15/x-31/x-63)
Programmable gain amplifier, non-inverting with external bias
or inverting mode with filtering
The procedure to use the OPAMP to amplify the amplitude of an input signal with bias
voltage for non-inverting mode or inverting mode with filtering
• configure VM_SEL bits as “Feedback resistor is connected to OPAMPx_VINM input”,
10
• configure PGA_GAIN bits as “Inverting gain = -1, -3, -7, -15, -31, -63 / Non-inverting
gain = 2, 4, 8, 16, 32, 64 with VINM0, VINM1 pin for filtering”, 11000 to 11101
• configure VP_SEL bits as “GPIO connected to OPAMPx_VINP”.
Any external connection on VINM1 can be used in parallel with the internal PGA, for
example a capacitor can be connected between opamp_out and VINM1 for filtering
purpose (see datasheet for the value of resistors used in the PGA resistor network).
STM32
+
-
VINM0
MSv48043V1
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)
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