LTC1387_15 Datasheet, PDF (8/12 Pages) Linear Technology – Single 5V RS232/RS485 Multiprotocol Transceiver

LTC1387
U
W
SWITCHI G WAVEFOR S
3V
D
0V
V_O
Z–Y
–V_O
Y
Z
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
1.5V
t_PLH
90%
50%
10%
t_r
V_DIFF = V(A) – V(B)
1/2 V_O
t_PHL
90%
50%
10%
t_f
V_O
t_SKEW
Figure 7. RS485 Driver Propagation Delays
t_{SKEW LTC1387 • F07}
3V
DXEN
0V
5V
Y, Z
V_OL
V_OH
Z, Y
0V
V_OD2
B–A
–V_OD2
V_OH
R
V_OL
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
1.5V
t_ZL
t_LZ
2.3V
OUTPUT NORMALLY LOW
0.5V
t_ZH
t_HZ
OUTPUT NORMALLY HIGH
0.5V
2.3V
Figure 8. RS485 Driver Enable and Disable Times
LTC1387 • F08
0V ^{f = 1MHz: tr ≤ 10ns: t f ≤ 10ns INPUT}
0V
t_PLH
1.5V
OUTPUT
t_PHL
1.5V
Figure 9. RS485 Receiver Propagation Delays
LTC1387 • F09
8
3V
D
0V
V_O
Y, Z
–V_O
1.5V
1.5V
t_PHL
t_PLH
0V
0V
Figure 10. RS232 Driver Propagation Delays
LTC1387 • F10