Datasheet

LTC1863/LTC1867
10
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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 defined as follows:
SD OS S1 S0 COM UNI SLP
SD = SINGLE/DIFFERENTIAL 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 configurations when COM = 0,
and COM = 1.
Table 1. Channel Configuration (When COM = 0, CH7/COM Pin
Is Used as CH7)
Channel Configuration
SD OS S1 S0 COM “+” “–”
0 0 0 0 0 CH0 CH1
0 0 0 1 0 CH2 CH3
0 0 1 0 0 CH4 CH5
0 0 1 1 0 CH6 CH7
0 1 0 0 0 CH1 CH0
0 1 0 1 0 CH3 CH2
0 1 1 0 0 CH5 CH4
0 1 1 1 0 CH7 CH6
1 0 0 0 0 CH0 GND
1 0 0 1 0 CH2 GND
1 0 1 0 0 CH4 GND
1 0 1 1 0 CH6 GND
1 1 0 0 0 CH1 GND
1 1 0 1 0 CH3 GND
1 1 1 0 0 CH5 GND
1 1 1 1 0 CH7 GND
Table 2. Channel Configuration (When COM = 1, CH7/COM Pin
Is Used as COMMON)
Channel Configuration
SD OS S1 S0 COM “+” “–”
1 0 0 0 1 CH0 CH7/COM
1 0 0 1 1 CH2 CH7/COM
1 0 1 0 1 CH4 CH7/COM
1 0 1 1 1 CH6 CH7/COM
1 1 0 0 1 CH1 CH7/COM
1 1 0 1 1 CH3 CH7/COM
1 1 1 0 1 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