5

 2000 Semtech Corp.

www.semtech.com

EDGE HIGH-PERFORMANCE PRODUCTS

Edge649

Circuit Description (continued)

Driver Output Protection

In a functional testing environment, where a resistor is

added in series with the driver output, the Edge649 can

withstand a short to any legal DUT voltage for an indefinite

amount of time.

In a low impedance application with no additional output

series resistance, care must be exercised and systems

should be designed to check for this condition and tristate

the driver if a short is detected.

Receiver Functionality

Edge649 suppor ts programmable thresholds per

channel. There are no shared lines between comparators.

THRESHOLD is a high input impedance analog input

which defines a logical “1” and “0” at the DUT (see

Figure 4).

If the DUT voltage is more positive than

THRESHOLD, DATA OUT will be high. With DUT lower

than THRESHOLD, DATA OUT will be low.

Figure 4. Receiver Functionality

DATA OUT

DUT

DUT

THRESHOLD

THRESHOLD

DATA OUT

Tpd

–

+