Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
_______________________________________________________Switching Waveforms
3V
0V
3V
0V
DE
DI
1.5V
1.5V
1.5V
1.5V
V
t
t
PHL
PLH
1/2 V
O
t
t
, t
LZ
ZL(SHDN) ZL
Z
Y, Z
V
2.3V
+0.5V
-0.5V
O
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
OL
V
OL
Y
1/2 V
O
V
= V (Y) - V (Z)
DIFF
Y, Z
0V
V
O
V
OH
2.3V
V
DIFF
90%
90%
0V
-V
10%
10%
O
t
, t
t
HZ
ZH(SHDN) ZH
t
R
t
F
t | t - t
SKEW = PLH PHL
|
Figure 8. Driver Propagation Delays
Figure 9. Driver Enable and Disable Times (except MAX488 and
MAX490)
3V
RE
1.5V
1.5V
0V
V
OH
t
LZ
t
, t
ZL(SHDN) ZL
RO
1.5V
1.5V
V
V
CC
OUTPUT
OL
RO
1.5V
V
V
+ 0.5V
- 0.5V
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
OL
t
t
PLH
PHL
V
ID
A-B
0V
0V
-V
ID
INPUT
RO
1.5V
OH
0V
t
, t
t
HZ
ZH(SHDN) ZH
Figure 11. Receiver Enable and Disable Times (except MAX488
and MAX490)
Figure 10. Receiver Propagation Delays
_________________Function Tables (MAX481/MAX483/MAX485/MAX487/MAX1487)
Table 1. Transmitting
Table 2. Receiving
INPUTS
OUTPUTS
INPUTS
OUTPUT
RE
DE
A-B
RO
RE
DE
DI
Z
Y
0
0
> +0.2V
1
0
1
X
1
1
0
1
0
0
0
0
0
< -0.2V
Inputs open
X
X
0
1
0
0
0
X
X
1
0
High-Z
High-Z
High-Z
1
High-Z
1
High-Z
*
*
*
X = Don't care
X = Don't care
High-Z = High impedance
Shutdown mode for MAX481/MAX483/MAX487
High-Z = High impedance
Shutdown mode for MAX481/MAX483/MAX487
*
*
10 ______________________________________________________________________________________
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
