Silicon Laboratories EFR32xG14 Wireless Gecko Reference Manual page 805

OPA Bitfields
OPAx POSSEL
OPAx NEGSEL
OPAx RESINMUX
24.3.4.4 Non-inverting PGA
Figure 24.6 Non-inverting PGA Overview on page 805
connected to the resistor ladder by setting the NEGSEL bit-field to OPATAP in VDACn_OPAx_MUX. This setting provides a program-
mable gain on the negative input, which is set by the RESSEL bit-field in VDACn_OPAx_MUX. In addition, the RESINMUX bit-field
must be set to VSS or NEGPAD in VDACn_OPAx_MUX. The positive input is selected by the POSSEL bit-field, and the output is con-
figured by VDACn_OPAx_OUT register.
OPA Bitfields
OPAx POSSEL
OPAx NEGSEL
OPAx RESINMUX
24.3.4.5 Cascaded Inverting PGA
This mode enables the opamp signals to be internally configured to cascade two or more opamps in inverting mode as shown in
24.7 Cascaded Inverting PGA Overview on page
POSSEL bit-field to PAD or APORT in VDACn_OPAx_MUX. When cascaded, the negative input is connected to the resistor ladder by
setting the NEGSEL bit-field to OPATAP in VDACn_OPAx_MUX. The input to the resistor ladder is configured by the RESINMUX bit-
field in VDACn_OPAx_MUX.
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Table 24.6. Inverting Input PGA Configuration
OPA Configuration
POSPADx, APORT[1-4]X
OPATAP
NEXTOUT, NEGPADx, POSPADx
shows the non-inverting input configuration. In this mode, the negative input is
VIN
+
-
R1
R2
Figure 24.6. Non-inverting PGA Overview
Table 24.7. Non-inverting PGA Configuration
OPA Configuration
NEXTOUT, POSPADx, APORT[1-4]X
OPATAP
VSS, NEGPAD
806. In both cases, the positive input is connected to signal ground by setting the
OPAMP - Operational Amplifier
VOUT
VOUT=VIN(1+ R2/R1)
Reference Manual
Figure
Rev. 1.1 | 805