Datasheet

LTC2870/LTC2871
15
28701f
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
28701 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
+
–
+
–
28701 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
28701 F10
0V OR V
L
DXEN/DX232
DRIVER
OUTPUT
C
L
R
L
t
HZD232
t
LZD232
DXEN/
DX232
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