Datasheet
LTC1863/LTC1867
9
18637fa
APPLICATIONS INFORMATION
Examples of Multiplexer Options
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7/COM
GND (
–
)
8 Single-Ended
+
+
+
+
+
+
+
4 Differential
+
(
–
)
+
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7/COM (
–
)
7 Single-Ended
to CH7/COM
+
+
+
+
+
+
+
+
(
–
)
+
(
–
)
+
(
–
)
–
(
+
)
–
(
+
)
–
(
+
)
–
(
+
)
GND (
–
)
Combinations of Differential
and Single-Ended
+
+
+
+
+
+
–
–
{
{
{
{
{
{
18637 AI01
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7/COM
CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7/COM
Analog Input Multiplexer
The analog input multiplexer is controlled by a 7-bit input
data word. The input data word is defi ned as follows:
SD OS S1 S0 COM UNI SLP
SD = SINGLE/DIFFERENT IAL BIT
OS = ODD/SIGN BIT
S1 = ADDRESS SELECT BIT 1
S0 = ADDRESS SELECT BIT 0
COM = CH7/COM CONFIGURATION BIT
UNI = UNIPOLAR/BIPOLAR BIT
SLP = SLEEP MODE BIT
Tables 1 and 2 show the confi gurations when COM = 0,
and COM = 1.
Table 1. Channel Confi guration (When COM = 0, CH7/COM Pin
Is Used as CH7)
Channel Confi guration
SD OS S1 S0 COM “+” “–”
00000 CH0 CH1
00010 CH2 CH3
00100 CH4 CH5
00110 CH6 CH7
01000 CH1 CH0
01010 CH3 CH2
01100 CH5 CH4
01110 CH7 CH6
10000 CH0 GND
10010 CH2 GND
10100 CH4 GND
10110 CH6 GND
11000 CH1 GND
11010 CH3 GND
11100 CH5 GND
11110 CH7 GND
Table 2. Channel Confi guration (When COM = 1, CH7/COM Pin
Is Used as COMMON)
Channel Confi guration
SD OS S1 S0 COM “+” “–”
10001 CH0 CH7/COM
10011 CH2 CH7/COM
10101 CH4 CH7/COM
10111 CH6 CH7/COM
11001 CH1 CH7/COM
11011 CH3 CH7/COM
11101 CH5 CH7/COM
Changing the MUX Assignment “On the Fly”
CH7/COM
(UNUSED)
CH7/COM (
–
)
1st Conversion 2nd Conversion
+
–
+
–
+
–
+
+
{
{
{
{
CH2
CH3
CH4
CH5
CH2
CH3
CH4
CH5
18637 AI02