sx8724s Semtech Corporation, sx8724s Datasheet - Page 21

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

Revision 1.0
© Semtech
As shown in
= AC7 - AC6), or AC0 can be used as a common reference, providing 7 signal paths all referred to AC0. The control word
for the analog input selection is Amux. Notice that the Amux bit 4 controls the sign of the input voltage.
Similarly, the reference voltage is chosen among two differential channels (V
V
be up to the power supply range.
7.4 First Stage Programmable Gain Amplifier (PGA1)
The first stage can have a buffer function (unity gain) or provide a gain of 10 (see
output of PGA1 is:
ADVANCED COMMUNICATIONS & SENSING
Sign S = 1
REF,IN
(RegACCfg5[5:1])
-V
Amux
10000
10001
10010
10011
10100
10101
10110
10111
00x00
00x01
00x10
00x11
SS
) as shown in
Table
8, the inputs can be configured in two ways: either as 4 differential channels (V
Table
1.
February 2011
AC1(V
AC1(V
AC0(V
V
AC3
AC5
AC7
AC2
AC3
AC4
AC5
AC6
AC7
INP
(RegACCfg5[0])
9. The selection bit is Vmux. The reference inputs V
External voltage reference on D1 GPIO pin. See
GPIO and “RegMode[0x70]” on page 48.
REF
REF
SS
)
)
)
Vmux
0
1
Table 9. Analog reference Input Selection
Table 8. Analog Input Selection
AC0(V
AC0(V
V
AC2
AC4
AC6
V
INN
D
SS
SS
1
V
)
)
REF
=
Page 21
Equation 5
GD
V
= V
REF
V
BG
1
REFP
= V
⋅
or V
V
Sign S = -1
BATT
IN
(RegACCfg5[5:1])
REF,IN
ZoomingADC for sensing data acquisition
1
[
Amux
11000
11001
11010
11011
11100
11101
11110
11111
01x00
01x01
01x10
01x11
V
section 6.3 on page 13
]
REF
= V
REFP
V
Table
V
V
REFN
SS
SS
BATT
and V
AC1(V
AC0(V
-V
V
10). The voltage V
AC2
AC4
AC6
INP
SS
about
REFN
SS
SS
, V
)
)
REF
(common-mode) can
SX8724S
= V
IN1
www.semtech.com
= AC1 - AC0,... , V
BG
DATASHEET
-V
SS
AC0(V
AC1(V
AC0(V
D1
or V
V
AC3
AC5
AC7
AC2
AC3
AC4
AC5
AC6
AC7
INN
at the
REF
REF
SS
REF
)
)
)
=
IN4