6

Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 50-668-707 • www.exar.com

SP48E,485E_00_2808

Figure 6. Driver Enable and Disable Times

Figure 8. Receiver Enable and Disable Times

+3V

0V

DE

5V

A,B

0V

1.5V

1.5V

A,B

2.3V

2.3V

0.5V

0.5V

Output normally LOW

Output normally HIGH

SWITCHING WAVEFORMS

FUNCTION TRUTH TABLES

INPUTS

OUTPUTS

RE

DE

DI

LINE

CONDITION

A

B

X





No Fault

0



X



0

No Fault



0

X

0

X

X

Z

Z

X



X

Fault

Z

Z

Table 1. Transmit Function Truth Table

INPUTS

OUTPUTS

RE

DE

A - B

R

0

0

+0.2V



0

0

-0.2V

0

0

0

Inputs Open





0

X

Z

Table 2. Receive Function Truth Table

R

1.5V

1.5V

OUTPUT

A – B

0V

0V

INPUT

≤

+3V

0V

5V

0V

1.5V

1.5V

R

1.5V

1.5V

0.5V

0.5V

Output normally LOW

Output normally HIGH

R

RE

Figure 7. Receiver Propagation Delays