SX8724C Datasheet, PDF (30/67 Pages) Semtech Corporation – ZoomingADC for sensing data acquisition

ADVANCED COMMUNICATIONS & SENSING
SX8724C
ZoomingADC for sensing data acquisition
DATASHEET
Table 16. Number of elementary conversion
SetOsr[2:0]
(RegACCfg[4:2])
00
01
10
11
# of Elementary Conversion
NELCONV [-]
1
2
4
8
As already mentioned, NELCONV must be equal or greater than 2 to reduce internal amplifier offsets.
7.7.5 Resolution
The theoretical resolution of the ADC, without considering thermal noise, is given by:
n = 2 ⋅ log₂(OSR) + log₂(N_ELCONV) [bit]
Equation 16
16.0
14.0
11
10
12.0
01
00
10.0
8.0
SetNelconv[1:0]
6.0
4.0
000
001
010
011
100
101
110
111
SetOsr[2:0]
Figure 15. Resolution vs. SetOsr[2:0] and SetNelconv[2:0]
Using look-up Table 17 or the graph plotted in Figure 15, resolution can be set between 6 and 16 bits. Notice that,
because of 16-bit register use for the ADC output, practical resolution is limited to 16 bits, i.e. n = 16. Even if the
Revision 1.01
© Semtech
January 2011
Page 30
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