Datasheet

Transition Time − ns
V − DifferentialOutput − V
OD
0.5
0.7
0.9
1.1
1.3
1.5
1.7
1.9
2.1
2.3
2.5
500 700 900
1100
1300 1500 1700
1900 2100 2300
2500 2700
V =5V
CC
R =50
C =50pF
L
L
W,
V =5.5V
CC
V =4.5V
CC
V =4V
CC
V =3.6V
CC
V =3.3V
CC
V =3V
CC
SN65HVD1780
SN65HVD1781
SN65HVD1782
SLLS877F –DECEMBER 2007–REVISED FEBRUARY 2010 www.ti.com
TYPICAL CHARACTERISTICS (continued)
HVD1780 DIFFERENTIAL OUTPUT AMPLITUDE and TRANSITION TIME
vs
SUPPLY VOLTAGE
Figure 13.
70-V Fault-Protection
The SN65HVD17xx family of RS-485 devices is designed to survive bus pin faults up to ±70V. The devices
designed for fast signaling rate (10 Mbps) will not survive a bus pin fault with a direct short to voltages above
30V when:
1. the device is powered on AND
2a. the driver is enabled (DE=HIGH) AND D=HIGH AND the bus fault is applied to the A pin OR
2b. the driver is enabled (DE=HIGH) AND D=LOW AND the bus fault is applied to the B pin
Under other conditions, the device will survive shorts to bus pin faults up to 70V. Table 1 summarizes the
conditions under which the device may be damaged, and the conditions under which the device will not be
damaged.
Table 1. Device Conditions
POWER DE D A B RESULTS
OFF X X -70V < V
A
< 70V -70V < V
B
< 70V Device survives
ON LO X -70V < V
A
< 70V -70V < V
B
< 70V Device survives
ON HI L -70V < V
A
< 70V -70V < V
B
< 30V Device survives
ON HI L -70V < V
A
< 70V 30V < V
B
Damage may occur
ON HI H -70V < V
A
< 30V -70V < V
B
< 30V Device survives
ON HI H 30V < V
A
-70V < V
B
< 30V Damage may occur
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