RS-485/RS-422 Transceivers with Preemphasis

for High-Speed, Long-Distance Communication

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5

TYPICAL PREEMPHASIS WAVEFORM

100ns/div

2V/

div

2500

0

0

1000

250

500

2250

200

100

300 400

600

500

800

700

900

2000

1750

750

1500

1250

1000

NOTE A

0

400

200

800

NOTE A

600

1000

1200

0

1000

500

1500

2000

0

1.0

0.5

2.0

1.5

2.5

3.0

4.0

3.5

4.5

10

30

40

50

20

60

70

80

90 100

DRIVER DIFFERENTIAL

STRONG

NORMAL

30.0

35.0

32.5

40.0

37.5

42.5

47.5

45.0

50.0

-40

0

20

-20

40

60

80

100

DRIVER PROPAGATION DELAY

vs. TEMPERATURE

TEMPERATURE (°C)

2.00

2.50

2.25

3.00

2.75

3.25

3.50

4.00

3.75

4.25

-40

0

20

-20

40

60

80

100

DRIVER DIFFERENTIAL

OUTPUT VOLTAGE vs. TEMPERATURE

TEMPERATURE (°C)

40.0

45.0

42.5

50.0

47.5

52.5

57.5

55.0

60.0

-40

0

20

-20

40

60

80

100

RECEIVER PROPAGATION DELAY

vs. TEMPERATURE

TEMPERATURE (°C)

RECEIVER PROPAGATION DELAY

20ns/div

RO

2.5V/

div

5V/

div

__________________________________________Typical Operating Characteristics

Note A: Dotted line represents region in which preemphasis may not work in systems with excessive power-supply noise. See

Preemphasis at Low Data Rates.