sx8724s Semtech Corporation, sx8724s Datasheet - Page 28

• Manufacturer Part Number: sx8724s
• Description: Zoomingadc For Sensing Data Acquisition
• Manufacturer: Semtech Corporation

Revision 1.0
© Semtech
resolution is truncated to 16 bit by the output register size, it may make sense to set OSR and N
in order to reduce the influence of the thermal noise in the PGA.
7.7.6 Conversion Time & Throughput
As explained in
and throughput is then simply 1/T
and a sampling frequency of 500 kHz (SetOsr = "101", SetNelconv = "01" and SetFs = "00"). In this case, using
the conversion time is 515 sampling periods, or 1.03ms. This corresponds to a throughput of 971Hz in continuous-time
mode. The plot of
ADVANCED COMMUNICATIONS & SENSING
Table 17. Normalized conversion time (Tconv x fs) vs. SetOsr and SetNelconv settings
Figure
1.
SetOsr
‘000‘
‘001‘
‘010‘
‘011‘
‘100‘
‘101‘
‘110‘
‘111‘
control bits
Figure 14
SetOsr bits
In shaded area, the resolution is truncated to 16 bits due to output register size RegA-
COut[15:0]
13, conversion time is given by:
‘000‘
‘001‘
‘010‘
‘011‘
OSR
February 2011
illustrates the classic trade-off between resolution and conversion time.
Table 16. Resolution
CONV
SetNelconv control bits
‘00‘
6
8
10
12
14
16
16
16
. For example, consider an over-sampling ratio of 256, 2 elementary conversions,
T
‘00‘
CONV
10
18
34
66
1
=
(
N
ELCONV
1
‘01‘
7
9
11
13
15
16
16
16
vs. SetOsr and SetNelconv settings
Equation 17
Page 28
⋅
(
SetNelconv control bits
‘01‘
131
OSR
19
35
67
2
+
N
) 1
ELCONV
ZoomingADC for sensing data acquisition
+
‘10‘
8
10
12
14
16
16
16
16
1
/ )
f
S
‘10‘
133
261
37
69
4
] [
s
‘11’
9
11
13
15
16
16
16
16
‘11‘
137
265
521
73
8
ELCONV
SX8724S
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to higher values
1
Table
17,