Datasheet

LTC2872
13
2872f
TesT circuiTs
Figure 8. RS485 Termination Resistance and Timing Measurements (Note 5)
Figure 9. RS232 Driver Timing and Slew Rate Measurements
Figure 10. RS232 Driver Enable and Disable Times
2872 F08
RECEIVER
V
AB
A
B
V
AB
I
A
R
TERM
=
V
B
½V
L
½V
L
TE485
I
A
I
A
90%
10%
t
RTZ485
t
RTEN485
0V
V
L
TE485
+
–
+
–
2872 F09
DRIVER
INPUT
DRIVER
OUTPUT
C
L
R
L
t
PHLD232
t
PLHD232
t
SKEWD232
= |t
PHLD232
– t
PLHD232
|
t
F
t
R
DRIVER
INPUT
DRIVER
INPUT
SLEW RATE =
6V
t
F
OR t
R
3V
–3V
0V
V
OLD
V
L
½V
L
½V
L
0V
3V
–3V
0V
V
OHD
2872 F10
0V OR V
L
DXEN
DRIVER
OUTPUT
C
L
R
L
t
HZD232
t
LZD232
DXEN
DRIVER
OUTPUT
DRIVER
OUTPUT
0.5V
t
ZHD232
t
ZLD232
5V
5V
0.5V
0V
0V
0V
V
OHD
V
L
½V
L
½V
L
V
OLD