SX8725C View Datasheet(PDF) - Semtech Corporation
Part Name
Description
MFG CO.
'SX8725C' PDF : 68 Pages View PDF
SX8725C
ZoomingADC for sensing data acquisition
ADVANCED COMMUNICATIONS & SENSING
DATASHEET
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):
0
D0/VREFOUT
1
GPIO
0
D0/VREFOUT
1
GPIO
RegMode[1] = 0
Internal
VBG
+
Bandgap
reference -
0 VREF
ZoomingADC
1
RegMode[1] = 0
Internal +
Bandgap
reference -
0 VREF
ZoomingADC
1
RegMode[0] = 0
RegMode[0] = 1
D1/VREFIN
1
GPIO
0
Figure 6. D0 and D1 are Digital Inputs / Outputs
D1/VREFIN
1
GPIO
0
Figure 7. D1 is Reference Voltage Input and D0 is Digital
Input / Output
0
D0/VREFOUT
1
GPIO
0
D0/VREFOUT
1
GPIO
RegMode[1] = 1
Internal
VBG
+
Bandgap
reference -
0 VREF
ZoomingADC
1
RegMode[1] = 1
Internal
VBG
+
Bandgap
reference -
0 VREF
ZoomingADC
1
RegMode[0] = 0
RegMode[0] = 1
D1/VREFIN
1
GPIO
0
D1/VREFIN
1
GPIO
0
Figure 8. D1 is Digital Input / Output and D0 Reference Figure 9. D0 is Reference Voltage Output and D1 is Reference
Voltage Output
Voltage Input
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 VREF output before feeding back as VREF,ADC input. The internally generated
VREF is a trimmed as ADC reference with a nominal value of 1.22V. When using an external VREF,ADC input, it may have
any value between 0V and VBATT. Simply substitute the external value for 1.22 V in the ADC conversion calculations.
Revision 1.01
© Semtech
January 2011
Page 16
www.semtech.com/products/
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