Datasheet

8
LTC1387
SWITCHI G WAVEFOR S
U
W
Figure 9. RS485 Receiver Propagation Delays
3V
D
Y, Z
–V
O
V
O
LTC1387 • F10
t
PHL
t
PLH
0V
0V
0V
1.5V
1.5V
Figure 10. RS232 Driver Propagation Delays
1.5V
3V
0V
D
f = 1MHz: t
r
≤ 10ns: t
f
≤ 10ns (FAST SLEW RATE MODE)
f = 100kHz: t
r
≤ 10ns: t
f
≤ 10ns (SLOW SLEW RATE MODE)
1.5V
Z – Y
–V
O
V
O
t
SKEW
1/2 V
O
LTC1387 • F07
t
PLH
t
r
90%
50%
10%
t
PHL
t
f
90%
50%
10%
V
O
t
SKEW
V
DIFF
= V(A) – V(B)
Z
Y
Figure 7. RS485 Driver Propagation Delays
1.5V
3V
0V
DXEN
f = 1MHz: t
r
≤ 10ns: t
f
≤ 10ns (FAST SLEW RATE MODE)
f = 100kHz: t
r
≤ 10ns: t
f
≤ 10ns (SLOW SLEW RATE MODE)
1.5V
Y, Z
V
OL
5V
t
ZL
t
LZ
0.5V
OUTPUT NORMALLY LOW
0V
LTC1387 • F08
2.3V
2.3V
t
ZH
V
OH
OUTPUT NORMALLY HIGH
t
HZ
0.5V
Z, Y
Figure 8. RS485 Driver Enable and Disable Times
0V
V
OD2
B – A
f = 1MHz: t
r
≤ 10ns: t
f
≤ 10ns
1.5V
R
V
OL
V
OH
LTC1387 • F09
t
PLH
t
PHL
INPUT
–V
OD2
OUTPUT
0V
1.5V