XE8000EV101 Semtech, XE8000EV101 Datasheet - Page 93

• Manufacturer Part Number: XE8000EV101
• Description: EVAL BOARD FOR XE8801AMI027LF
• Manufacturer: Semtech
• Type: MCUr

Specifications of XE8000EV101

• Contents: Fully Assembled Evaluation Board
• For Use With/related Products: XE88LC01AMI027
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

16.5 Input Multiplexers
The ZoomingADC™ has eight analog inputs AC_A(0) to AC_A(7) and four reference inputs AC_R(0) to AC_R(3).
Let us first define the differential input voltage V
and:
As shown in Table 16-11 the inputs can be configured in two ways: either as 4 differential channels (V
- AC_A(0),..., V
paths all referred to AC_A(0). The control word for the analog input selection is AMUX[4:0]. Notice that the bit
AMUX[3] controls the sign of the input voltage.
Similarly, the reference voltage is chosen among two differential channels (V
AC_R(3)-AC_R(2)) as shown in Table 16-12. The selection bit is VMUX. The reference inputs V
(common-mode) can be up to the power supply range.
© Semtech 2005
V
(RegAcCfg5[5:1])
V
IN
REF
AMUX[4:0]
=
V
=
00x00
00x01
00x10
00x11
10000
10001
10010
10011
10100
10101
10110
10111
INP
V
REFP
IN4
−
V
INN
= AC_A(7) - AC_A(6)), or AC_A(0) can be used as a common reference, providing 7 signal
−
V
REFN
AC_A(1)
AC_A(3)
AC_A(5)
AC_A(7)
AC_A(0)
AC_A(1)
AC_A(2)
AC_A(3)
AC_A(4)
AC_A(5)
AC_A(6)
AC_A(7)
V
(V)
(V)
INP
(RegAcCfg5[0])
Table 16-12. Analog Reference input selection
VMUX
AC_A(0)
AC_A(2)
AC_A(4)
AC_A(6)
AC_A(0)
0
1
V
Table 16-11. Analog input selection
INN
IN
and reference voltage V
AC_R(1)
AC_R(3)
V
(RegAcCfg5[5:1])
16-8
REFP
AMUX[4:0]
01x00
01x01
01x10
01x11
11000
11001
11010
11011
11100
11101
11110
11111
AC_R(0)
AC_R(2)
V
REFN
(Eq. 3)
(Eq. 4)
REF
AC_A(0)
AC_A(2)
AC_A(4)
AC_A(6)
AC_A(0)
respectively as:
REF1
V
INP
= AC_R(1)-AC_R(0) or V
XE8801A – SX8801R
AC_A(1)
AC_A(3)
AC_A(5)
AC_A(7)
AC_A(0)
AC_A(1)
AC_A(2)
AC_A(3)
AC_A(4)
AC_A(5)
AC_A(6)
AC_A(7)
V
INN
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REFP
IN1
= AC_A(1)
and V
REF2
REFN
=