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TLC2543-EP

12-BIT ANALOG-TO-DIGITAL CONVERTER

WITH SERIAL CONTROL AND 11 ANALOG INPUTS

SGLS125A – JULY 2002 – REVISED NOVEMBER 2006

TERMINAL FUNCTIONS

TERMINAL

I/O

DESCRIPTION

NAME

NO.

AIN0

1

AIN1

2

AIN2

3

AIN3

4

AIN4

5

Analog input. These 11 analog-signal inputs are internally multiplexed. The driving source

AIN5

6

I

impedance should be less than or equal to 50

Ω for 4.1-MHz I/O CLOCK operation, and be capable

AIN6

7

of slewing the analog input voltage into a capacitance of 60 pF.

AIN7

8

AIN8

9

AIN9

11

AIN10

12

Chip select. A high-to-low transition on CS resets the internal counters and controls and enables

CS

15

I

DATA OUT, DATA INPUT, and I/O CLOCK. A low-to-high transition disables DATA INPUT and I/O

CLOCK within a setup time.

Serial-data input. A 4-bit serial address selects the desired analog input or test voltage to be

converted next. The serial data is presented with the most significant bit (MSB) first and is shifted in

DATA INPUT

17

I

on the first four rising edges of I/O CLOCK. After the four address bits are read into the address

register, I/O CLOCK clocks the remaining bits in order.

The 3-state serial output for the A/D conversion result. DATA OUT is in the high-impedance state

when CS is high and active when CS is low. With a valid CS, DATA OUT is removed from the

high-impedance state and is driven to the logic level corresponding to the most significant bit/least

DATA OUT

16

O

significant bit (MSB/LSB) value of the previous conversion result. The next falling edge of I/O

CLOCK drives DATA OUT to the logic level corresponding to the next MSB/LSB, and the remaining

bits are shifted out in order.

End of conversion. EOC goes from a high to a low logic level after the falling edge of the last I/O

EOC

19

O

CLOCK and remains low until the conversion is complete and the data is ready for transfer.

Ground. GND is the ground return terminal for the internal circuitry. Unless otherwise noted, all

GND

10

voltage measurements are with respect to GND.

Input/output clock. I/O CLOCK receives the serial input and performs the following four functions:

• It clocks the eight input data bits into the input data register on the first eight rising edges of I/O

CLOCK with the multiplexer address available after the fourth rising edge.

• On the fourth falling edge of I/O CLOCK, the analog input voltage on the selected multiplexer input

begins charging the capacitor array and continues to do so until the last falling edge of the I/O

I/O CLOCK

18

I

CLOCK.

• It shifts the 11 remaining bits of the previous conversion data out on DATA OUT. Data changes on

the falling edge of I/O CLOCK.

• It transfers control of the conversion to the internal state controller on the falling edge of the last

I/O CLOCK.

REF+

14

I

The maximum input voltage range is determined by the difference between the voltage applied to

this terminal and the voltage applied to the REF– terminal.

Negative reference voltage. The lower reference voltage value (nominally ground) is applied to

REF–

13

I

REF–.

20

Positive supply voltage

3

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