HD26LS32

9

This circuit provides for the receiver input section to be pulled up or down by a high resistance that

prevents it from becoming a driver load so that the output goes high in the event of a transmission line

breakage or connector detachment.

When the input pin is placed in the open state by the pull-up/pull-down resistance, the differential input

voltage V

V

(V

and the output is fixed high.

However, if the receiver-side termination resistance remains connected despite a line breakage or connector

detachment, the output will be undetermined (figure 5).

1Y

2Y

3Y

4Y

1A

1B

2A

2B

3A

3B

4A

4B

Enable G

Enable G

Figure 1 HD26LS32 Block Diagram

5

4

3

2

1

0

–1

–2

–3

–4

–5

–25 –20 –15 –10 –5

0

5

10 15 20 25

Input Voltage Vin (V)

Ta = 25

°C

+3.25 mA

=

0

V

=

5.25

V

–3.25 mA

–10 V –3 V

+3 V +10 V

Figure 2 Input Voltage vs. Input Current Characteristics