sx8725c Semtech Corporation, sx8725c Datasheet - Page 16

• Manufacturer Part Number: sx8725c
• Description: Zoomingadc For Sensing Data Acquisition
• Manufacturer: Semtech Corporation

Revision 1.01
© Semtech
6.3.1 Optional Operating Mode: External Vref
D0 and D1 are multi-functional pins with the following functions in different operating modes (see RegMode register
for control settings):
This allows external monitoring of the internal bandgap reference or the ability to use an external reference input for
the ADC, or the option to filter the internal V
V
any value between 0V and V
ADVANCED COMMUNICATIONS & SENSING
REF
D0/VREF
D0/VREF
D1/VREF
D1/VREF
Figure 8. D1 is Digital Input / Output and D0 Reference
is a trimmed as ADC reference with a nominal value of 1.22V. When using an external V
Figure 6. D0 and D1 are Digital Inputs / Outputs
OUT
OUT
IN
IN
reference
reference
Bandgap
Bandgap
Internal
Internal
+
-
+
-
Voltage Output
RegMode[1] = 0
V
V
RegMode[1] = 1
BG
BG
January 2011
0
1
0
1
BATT
. Simply substitute the external value for 1.22 V in the ADC conversion calculations.
RegMode[0] = 0
RegMode[0] = 0
0
1
1
0
0
1
1
0
V
V
REF
REF
REF
GPIO
ZoomingADC
GPIO
GPIO
ZoomingADC
GPIO
output before feeding back as V
Page 16
Figure 9. D0 is Reference Voltage Output and D1 is Reference
D0/VREF
D0/VREF
D1/VREF
D1/VREF
Figure 7. D1 is Reference Voltage Input and D0 is Digital
ZoomingADC for sensing data acquisition
OUT
OUT
IN
IN
reference
reference
Bandgap
Bandgap
Internal
Internal
REF,ADC
+
+
-
-
RegMode[1] = 1
V
RegMode[1] = 0
Input / Output
Voltage Input
BG
0
1
0
1
input. The internally generated
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REF,ADC
RegMode[0] = 1
RegMode[0] = 1
SX8725C
0
1
1
0
0
1
1
0
input, it may have
DATASHEET
V
V
REF
REF
GPIO
ZoomingADC
GPIO
GPIO
ZoomingADC
GPIO