LTC2872
TesT circuiTs
I
, I
OZD485 OSD485
Y OR Z
Z OR Y
Y
Z
R
R
L
GND
OR
GND
DY
+
DY
OR
DRIVER
DRIVER
V
OD
V
L
V
L
+
–
V
OUT
–
+
L
V
OC
–
2872 F02
2872 F01
Figure 1. RS485 Driver DC Characteristics
Figure 2. RS485 Driver Output Short-Circuit Current
I
IN485
A OR B
B OR A
RECEIVER
+
–
V
IN
V
IN
R
=
IN485
I
2872 F03
IN485
Figure 3. RS485 Receiver Input Current and Resistance (Note 5)
V
L
t
t
PLHD485
DY
Y, Z
PLHD485
Y
Z
0V
t
SKEWD485
C
C
L
L
DY
V
½V
OD
OD
R
DIFF
DRIVER
90%
10%
90%
10%
0V
0V
Y - Z
t
t
FD485
RD485
2872 F04
Figure 4. RS485 Driver Timing Measurement
2872f
11
Linear Systems [ Linear Systems ]
