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2016-04-28 - Giant Gecko Family - d0053_Rev1.20
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OPA2 by setting the NEXTOUT bit-field in DACn_OPA1MUX and OPA2RESINMUX to OPA1INP in
DACn_OPA2MUX. In addition the OPA2POSSEL must be set to 0PATAP. The OPA2 output can be
configured by configuring the OUTPEN and OUTMODE bit-field.
Figure 30.10. Three Op-amp Differential Amplifier Overview
R1
R2
V2
-
+
VOUT
VOUT= (V2- V1)R2/ R1
R1
R2
-
+
-
+
V1
OPA1
OPA0
OPA2
The gain values for the Three Opamp Differential Amplifier is determined by the combination of the gain
settings of OPA0 and OPA2. The 3 different gain values available, 1/3, 1 and 3, can be programmed
as shown in the table below.
Table 30.9. Three Opamp Differential Amplifier Gain Programming
Gain
OPA0 RESSEL
OPA2 RESSEL
1/3
4
0
1
1
1
3
0
4
Table 30.10. Three Opamp Differential Amplifier Configuration
OPA
OPA bit-fields
OPA Configuration
OPA0
POSSEL
POSPAD
OPA0
NEGSEL
UG
OPA0
RESINMUX
DISABLE
OPA1
POSSEL
POSPAD
OPA1
NEGSEL
UG
OPA1
RESINMUX
DISABLE
OPA1
NEXTOUT
1
OPA2
POSSEL
OPATAP
OPA2
NEGSEL
OPATAP
OPA2
RESINMUX
OPA1INP
30.3.2.9 Dual Buffer ADC Driver
It is possible to use OPA0 and OPA1 to form a Dual Buffer ADC driver as shown in Figure 30.11 (p.
743) . Both opamps used can be configured in the same way. The positive input is configured by
setting the 0PAxPOSSEL to PAD and the negative input can be connected to the resistor ladder by
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