Low-Power, Slew-Rate-Limited
RS-485/RS-422 Transceivers
MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487
_______________________________________________________Switching Waveforms
3V
DI
0V
1.5V
t
PLH
t
PHL
1.5V
1/2 V
O
t
ZL(SHDN)
, t
ZL
Y, Z
V
O
Y
1/2 V
O
V
O
V
DIFF
0V
-V
O
10%
t
R
t
SKEW =
| t
PLH
- t
PHL
|
V
DIFF
= V (Y) - V (Z)
90%
90%
t
F
10%
V
OL
Y, Z
2.3V
0V
t
ZH(SHDN)
, t
ZH
t
HZ
2.3V OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
V
OH
-0.5V
V
OL
+0.5V
t
LZ
DE
0V
3V
1.5V
1.5V
Z
Figure 8. Driver Propagation Delays
Figure 9. Driver Enable and Disable Times (except MAX488 and
MAX490)
3V
RE
0V
RO
V
OH
V
OL
V
ID
-V
ID
0V
1.5V
t
PHL
INPUT
OUTPUT
t
PLH
0V
RO
0V
t
ZH(SHDN)
, t
ZH
t
HZ
1.5V
1.5V
V
CC
RO
t
ZL(SHDN)
, t
ZL
t
LZ
V
OL
+ 0.5V
1.5V
1.5V
1.5V OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
A-B
V
OH
- 0.5V
Figure 10. Receiver Propagation Delays
Figure 11. Receiver Enable and Disable Times (except MAX488
and MAX490)
_________________Function Tables
(MAX481/MAX483/MAX485/MAX487/MAX1487)
Table 1. Transmitting
INPUTS
RE
X
X
0
1
DE
1
1
0
0
DI
1
0
X
X
Z
0
1
High-Z
High-Z
*
OUTPUTS
Y
1
0
High-Z
High-Z
*
RE
0
0
0
1
Table 2. Receiving
INPUTS
DE
0
0
0
0
A-B
> +0.2V
< -0.2V
Inputs open
X
OUTPUT
RO
1
0
1
High-Z
*
X = Don't care
High-Z = High impedance
*
Shutdown mode for MAX481/MAX483/MAX487
X = Don't care
High-Z = High impedance
*
Shutdown mode for MAX481/MAX483/MAX487
10
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MAXIM [ MAXIM INTEGRATED PRODUCTS ]
