TC520A

DS21431B-page 8

© 2002 Microchip Technology Inc.

FIGURE 4-1:

TC520 initialization & startup conversion timing relatioNships

FIGURE 4-2:

lOad value modify cycle

4.4.6

OPTO-ISOLATED APPLICATIONS

The 3 wire serial port of the TC520A can be opto-

isolated for applications requiring isolated data acquisi-

tion. The additional control lines (LOAD,DV, READ)

are normally not needed in such applications, but can

also be brought across the isolation barrier with the

addition of a second isolator.

LOAD

LOAD VALUE updated

and conversion started

TC520A Conversion State

CE is pulled

high only during

AZ (DV = Low)

New LOAD VALUE

can be loaded

(if so desired)

TC520A held in

AZ phase

as long as CE = HIGH

CE

AZ

INT

IZ

DINT

AZ

INT

INT

DINT

IZ

AZ

AZ

DIN, DCLK

DV

LOAD VALUE

shifted into

DIN

Load

Value

LOAD

LOAD VALUE updated

and conversion started

TC520A Conversion State

CE

AZ

INT

IZ

DINT

AZ

INT

INT

DINT

IZ

AZ

DV

LOAD VALUE

shift into