TLC2543C, TLC2543I, TLC2543M

12-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

SLAS079F – DECEMBER 1993 – REVISED NOVEMBER 2001

14

POST OFFICE BOX 655303

PRINCIPLES OF OPERATION

data input

The data input is internally connected to an 8-bit serial-input address and control register. The register defines

the operation of the converter and the output data length. The host provides the data word with the MSB first.

Each data bit is clocked in on the rising edge of the I/O CLOCK sequence (see Table 2 for the data input-register

format).

Table 2. Input-Register Format

INPUT DATA BYTE

FUNCTION SELECT

ADDRESS BITS

L1

L0

LSBF

BIP

FUNCTION SELECT

D7

(MSB)

D6

D5

D4

D3

D2

D1

D0

(LSB)

Select input channel

AIN0

AIN1

AIN2

AIN3

AIN4

AIN5

AIN6

AIN7

AIN8

AIN9

AIN10

0

0

0

0

0

0

0

0

1

1

1

0

0

0

0

1

1

1

1

0

0

0

0

0

1

1

0

0

1

1

0

0

1

0

1

0

1

0

1

0

1

0

1

0

Select test voltage

(Vref + – Vref –)/2

Vref –

Vref +

1

1

1

0

1

1

1

0

0

1

0

1

Software power down

1

11

0

Output data length

8 bits

12 bits

16 bits

0

X†

1

1

0

1

Output data format

MSB first

LSB first (LSBF)

0

1

Unipolar (binary)

0

Bipolar (BIP) 2s complement

1

† X represents a do not care condition.

data input address bits

The four MSBs (D7 – D4) of the data register address one of the 11 input channels, a reference-test voltage,

or the power-down mode. The address bits affect the current conversion, which is the conversion that