SX8801IRXXMLTRT View Datasheet(PDF) - Semtech Corporation
Part Name
Description
MFG CO.
'SX8801IRXXMLTRT' PDF : 135 Pages View PDF
XE8801A – SX8801R
OUTADC
= 216 ⋅ VIN , ADC
VREF
⋅ OSR + 1
OSR
(LSB)
Recalling equation Eq. 9, this can be rewritten as:
(Eq.17)
OUTADC
= 216 ⋅ VIN
VREF
⋅ ⎜⎜⎝⎛GDTOT
− GDoffTOT
⋅ VREF
VIN
⎟⎟⎠⎞
⋅ OSR +1
OSR
(LSB) (Eq. 18)
where, from Eq. 10 and Eq. 11, the total PGA gain and offset are respectively:
and:
GDTOT = GD3 ⋅ GD2 ⋅ GD1
(V/V)
GDoffTOT = GDoff3 + GD3 ⋅ GDoff 2
(V/V)
ADC Input
Voltage
VIN,ADC
+2.49505V
% of
Full
Scale
(FS)
+0.5⋅FS
+2.49497V
...
...
...
+76.145µV
...
0V
0
-76.145µV
...
...
...
-2.49505V
...
-2.49513V -0.5⋅FS
Output in
LSBs
+215-1
=+32'767
+215-2
=+32'766
...
+1
0
-1
...
-215-1
=-32'767
-215
=-32'768
Output
Code
in Hex
7FFF
7FFE
...
0001
0000
FFFF
...
8001
8000
Table 16-24. Basic ADC Relationships (example for: VREF = 5V, OSR = 512, n = 16 bits)
SET_OS
R
[2:0]
000
001
010
011
100
101
110
111
SET_NELC = 00
1000000000
10000000
100000
1000
10
-
-
-
SET_NELC = 01 SET_NELC = 10 SET_NELC = 11
100000000
1000000
10000
100
1
-
-
-
10000000
100000
1000
10
-
-
-
-
1000000
10000
100
1
-
-
-
-
Table 16-25. Last forced LSBs in conversion output registers for resolution settings smaller than 16
bits (n < 16) (RegAcOutMsb[7:0] & RegAcOutLsb[7:0])
© Semtech 2005
16-16
www.semtech.com
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