TLC548C, TLC548I, TLC549C, TLC549I

8-BIT ANALOG-TO-DIGITAL CONVERTERS

WITH SERIAL CONTROL

SLAS067C – NOVEMBER 1983 – REVISED SEPTEMBER 1996

9

POST OFFICE BOX 655303

PRINCIPLES OF OPERATION

For certain applications, such as strobing applications, it is necessary to start conversion at a specific point in time.

This device accommodates these applications. Although the on-chip sample-and-hold function begins sampling

upon the high-to-low transition of the fourth I/O CLOCK cycle, the hold function does not begin until the high-to-low

transition of the eighth I/O CLOCK cycle, which should occur at the moment when the analog signal must be

converted. The TLC548 and TLC549 continue sampling the analog input until the high-to-low transition of the eighth

I/O CLOCK pulse. The control circuitry or software then immediately lowers I/O CLOCK and starts the holding function

to hold the analog signal at the desired point in time and starts the conversion.