5

®

ISO808

FIGURE 1. Basic Conversion Timing.

MODE Acquire

t

4

t

5

t

1

t

3

t

7

t

6

Convert

Acquire

t

2

BUSY

R/C

1

MSB Valid

R/C

DATACLK

SDATA

t

8

t

11

t

10

t

9

2

3

11

12

Bit 10 Valid

Bit 1 Valid

Bit 9 Valid

LSB Valid

t

2

t

3

BUSY

FIGURE 2. Serial Data Timing.

SPECIFIC FUNCTION

R/C

BUSY

DATACLK

SB/BTC

OPERATION

TABLE III. Control Truth Table.

Initiate Conversion and Output Data

0

1

Output

X

Initiates Conversion “n”. Data from conversion “n–1” clocked out

on DATA synchronized to 12 clock pulses output on DATACLK.

1 > 0

1

Output

X

Initiates Conversion “n”. Data from conversion “n–1” clocked out

on DATA synchronized to 12 clock pulses output on DATACLK.

Incorrect Conversions

0

0 > 1

X

X

R/C must be HIGH or a new conversion will be initiated without

time for acquisition.

Selecting Output Format

X

X

X

0

Serial Data is output in Binary Two’s Complement format.

X

X

X

1

Serial Data is output in Straight Binary format.

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)

ANALOG INPUT

DIGITAL OUTPUT

TABLE IV. Output Codes and Ideal Input Voltages.