sx8725 Semtech Corporation, sx8725 Datasheet - Page 24

• Manufacturer Part Number: sx8725
• Description: Sx8725 Zoomingadc? For Pressure And Temperature Sensing
• Manufacturer: Semtech Corporation

ADVANCED COMMUNICATIONS & SENSING
Resolution
The theoretical resolution of the ADC, without considering thermal noise, is given by:
Using look-up Table 13 or the graph plotted in Figure 12, resolution can be set between 6 and 16 bits. Notice
that, because of 16-bit register use for the ADC output, practically the resolution is limited to 16 bits,
i.e. n
OSR and N
external noises (see section “PGA Gain & Offset, Linearity and Noise” in page 37).
V1.5 © 2007 Semtech Corp.
16. Even though the resolution is truncated to 16 bit by the output register size, it may make sense to set
ELCONV
Table 13 - Resolution vs. SET_OSR[2:0] and SET_NELC[1:0] Settings
to higher values in order to reduce the influence of the thermal noise in the PGA and of
Figure 12 - Resolution vs. SET_OSR[2:0] and SET_NELC[1:0]
output register size RegACOut[15:0]
Note: shaded area: resolution truncated to 16 bits due to
SET_OSR
n
[2:0]
000
001
010
011
100
101
110
111
2
17
15
13
11
9
7
5
log
000
ZoomingADC™ for Pressure and Temperature Sensing
SET_NELC=
2
001
OSR
00
10
12
14
16
16
16
6
8
Equation 15
010
11
10
01
00
24
log
SET_OSR
011
SET_NELC[1:0]
01
11
13
15
16
16
16
7
9
2
100
N
ELCONV
101
10
10
12
14
16
16
16
16
8
110
111
(Bits)
11
11
13
15
16
16
16
16
9
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SX8725