Datasheet

ADS7808
6
SBAS018A
www.ti.com
HEX HEX
DESCRIPTION BINARY CODE CODE BINARY CODE CODE
Full-Scale Range ±10 ±5 ±3.33V 0V to 5V 0V to 10V 0V to 4V
Least Significant Bit (LSB) 4.88mV 2.44mV 1.63mV 1.22mV 2.44mV 0.98mV
+Full Scale (FS – 1LSB) 9.99512V 4.99756V 3.33171V 4.99878V 9.99756V 3.99902V 0111 1111 1111 7FF 1111 1111 1111 FFF
Midscale 0V 0V 0V 2.5V 5V 2V 0000 0000 0000 000 1000 0000 0000 800
One LSB Below Midscale –4.88mV –2.44mV –1.63mV 2.49878V 4.99756V 1.99902V 1111 1111 1111 FFF 0111 1111 1111 7FF
–Full Scale –10V –5V –3.333333V 0V 0V 0V 1000 0000 0000 800 0000 0000 0000 000
BINARY TWO’S
COMPLEMENT STRAIGHT BINARY
(SB/BTC LOW) (SB/BTC HIGH)
Initiate Conversion and
Output Data Using External
Clock
Power Down
Selecting Output Format
Incorrect Conversions
SPECIFIC FUNCTION CS R/C BUSY EXT/INT DATACLK PWRD SB/BTC OPERATION
Initiate Conversion and 1>0 0 1 0 Output 0 x Initiates conversion “n”. Data from conversion “n–1”
Output Data Using clocked out on DATA synchronized to 12 clock
Internal Clock pulses output on DATACLK.
0 1>0 1 0 Output 0 x Initiates conversion “n”. Data from conversion “n–1”
clocked out on DATA synchronized to 12 clock
pulses output on DATACLK.
1>0 0 1 1 Input 0 x Initiates conversion “n”.
0 1>0 1 1 Input 0 x Initiates conversion “n”.
1>0 1 1 1 Input x x Outputs a pulse on SYNC followed by data from
conversion “n” clocked out synchronized to external
DATACLK.
1>0 1 0 1 Input 0 x Outputs a pulse on SYNC followed by data from
conversion “n–1” clocked out synchronized to
external DATACLK.
(1)
Conversion “n” in process.
0 0>1 0 1 Input 0 x Outputs a pulse on SYNC followed by data from
conversion “n–1” clocked out synchronized to
external DATACLK .
(1)
Conversion “n” in process.
0 0 0>1 x x 0 x CS or R/C must be HIGH or a new conversion will
be initiated without time for acquisition.
x x x x x 0 x Analog circuitry powered. Conversion can proceed.
x x x x x 1 x Analog circuitry disabled. Data from previous
conversion maintained in output registers.
x x x x x x 0 Serial data is output in Binary Two’s Complement
format.
x x x x x x 1 Serial data is output in Straight Binary format.
NOTE: (1) See Figure 3b for constraints on previous data valid during conversion.
Table III. Control Truth Table.
ANALOG INPUT
DIGITAL OUTPUT
Table IV. Output Codes and Ideal Input Voltages.