
8
LTC1387
SWITCHI G WAVEFOR S
U
W
Figure 9. RS485 Receiver Propagation Delays
3V
D
Y, Z
–VO
VO
LTC1387 F10
tPHL
tPLH
0V
1.5V
Figure 10. RS232 Driver Propagation Delays
1.5V
3V
0V
D
f = 1MHz: t r ≤ 10ns: tf ≤ 10ns (FAST SLEW RATE MODE)
f = 100kHz: t r ≤ 10ns: tf ≤ 10ns (SLOW SLEW RATE MODE)
1.5V
Z – Y
–VO
VO
tSKEW
1/2 VO
LTC1387 F07
tPLH
tr
90%
50%
10%
tPHL
tf
90%
50%
10%
VO
tSKEW
VDIFF = V(A) – V(B)
Z
Y
Figure 7. RS485 Driver Propagation Delays
1.5V
3V
0V
DXEN
f = 1MHz: t r ≤ 10ns: tf ≤ 10ns (FAST SLEW RATE MODE)
f = 100kHz: t r ≤ 10ns: tf ≤ 10ns (SLOW SLEW RATE MODE)
1.5V
Y, Z
VOL
5V
tZL
tLZ
0.5V
OUTPUT NORMALLY LOW
0V
LTC1387 F08
2.3V
tZH
VOH
OUTPUT NORMALLY HIGH
tHZ
0.5V
Z, Y
Figure 8. RS485 Driver Enable and Disable Times
0V
VOD2
B – A
f = 1MHz: tr ≤ 10ns: tf ≤ 10ns
1.5V
R
VOL
VOH
LTC1387 F09
tPLH
tPHL
INPUT
–VOD2
OUTPUT
0V
1.5V