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Table 30.6. Cascaded Non-inverting PGA Configuration
OPA
OPA0
OPA0
OPA0
OPA0
OPA1
OPA1
OPA1
OPA1
OPA2
OPA2
OPA2
OPA bit-fields
POSSEL
NEGSEL
RESINMUX
NEXTOUT
POSSEL
NEGSEL
RESINMUX
NEXTOUT
POSSEL
NEGSEL
RESINMUX
OPA Configuration
POSPAD0
OPATAP
VSS, NEGPAD0
1
OPA0INP
OPATAP
VSS, NEGPAD1
1
OPA1INP
OPATAP
VSS, NEGPAD2
30.3.2.7 Two Opamp Differential Amplifier
This mode enables OPA0 and OPA1 or OPA1 and OPA2 to be internally configured to form a two opamp
differential amplifier as shown in Figure 30.9 (p. 733) . When using OPA0 and OPA1, the positive input
of OPA0 can be connected to any input by configuring the OPA0POSSEL bit-field in DACn_OPA0MUX.
The OPA0 feedback path must be configured to unity gain by setting the OPA0NEGSEL bit-field to UG in
DACn_OPA0MUX. In addition, the OPA0RESINMUX bit-field must be set to DISABLED. The OPA0OUT
must be connected to OPA1 by setting NEXTOUT in DACn_OPA0MUX, and OPA1RESINMUX to
OPA0INP. The positive input on OPA1 can be set by configuring OPA1POSSEL. The OPA1 output can
be configured by configuring the OUTPEN and OUTMODE bit-field.
When using OPA1 and OPA2, the positive input of OPA1 can be connected to any input by configuring
the OPA1POSSEL bit-field in DACn_OPA1MUX. The OPA1 feedback path must be configured to unity
gain by setting the OPA1NEGSEL bit-field to UG in DACn_OPA1MUX. In addition, the OPA1RESINMUX
bit-field must be set to DISABLED. The OPA1OUT must be connected to OPA2 by setting NEXTOUT
in DACn_OPA1MUX, and OPA2RESINMUX to OPA1INP. The positive input on OPA2 can be set
by configuring OPA2POSSEL. The OPA2 output can be configured by configuring the OUTPEN and
OUTMODE bit-field.
Note
When making a differential connection with the ADC, only OPA1 and OPA2 can be used
2013-05-08 - Wonder Gecko Family - d0233_Rev0.50
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