THS1209 Datasheet, PDF (21/33 Pages) Texas Instruments – 12-BIT, 2 ANALOG INPUT, 8MSPS, SIMULTANEOUS SAMPLING ANALOG-TO-DIGITAL CONVERTER

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ANALOG INPUT CHANNEL SELECTION
THS1209
SLAS288B – JULY 2000 – REVISED DECEMBER 2002
The analog input channels of the THS1209 can be selected via bits 3 to 7 of control register 0. One single channel
(single-ended or differential) is selected via bit 3 and bit 4 of control register 0. Bit 5 controls the selection between
single-ended and differential configuration. Bit 6 and bit 7 select the autoscan mode, if more than one input channel
is selected. Table 9 shows the possible selections.
BIT 7
AS
0
0
0
0
0
0
1
1
1
1
1
1
0
0
1
1
1
1
1
1
1
1
1
1
BIT 6
DF1
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
1
1
1
1
1
1
1
BIT 5
DF0
0
0
0
0
1
1
0
0
0
0
1
1
1
1
0
1
1
0
0
0
1
1
1
1
Table 9. Analog Input Channel Configurations
BIT 4
CHS1
0
0
1
1
0
0
0
1
1
0
0
1
1
1
0
0
1
0
1
1
0
0
1
1
BIT 3
CHS0
0
1
0
1
0
1
1
0
1
1
1
0
0
1
0
0
1
0
0
1
0
1
0
1
DESCRIPTION OF THE SELECTED INPUTS
Analog input AINP (single ended)
Analog input AINM (single ended)
Reserved
Reserved
Differential channel (AINP–AINM)
Reserved
Autoscan two single ended channels: AINP, AINM, AINP, …
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Test Mode
The test mode of the ADC is selected via bit 8 and bit 9 of control register 0. The different selections are shown in
Table 10.
Table 10. Test Mode
BIT 9
TEST1
0
0
1
1
BIT 8
TEST0
0
1
0
1
OUTPUT RESULT
Normal mode
VREFP
((VREFM)+(VREFP))/2
VREFM
Three different options can be selected. This feature allows support testing of hardware connections between the
ADC and the processor.
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