Datasheet

MAX3291/MAX3292
RS-485/RS-422 Transceivers with Preemphasis
for High-Speed, Long-Distance Communication
8 _______________________________________________________________________________________
DI
DE
D
5V
Y
Z
C
L1
C
L2
R
DIFF
V
ODP
RE
RO
DE = LOW
t > t
SHDN
t < t
SHDN
t
RZH(SHDN)
Figure 3. Driver Timing Test Circuit Figure 4. Shutdown Timing Diagram
DI
5V
0
Z
N
Y
P
Z
P
Y
N
Z
N
Z
P
Y
P
Y
N
0 DIFFERENTIAL
0 DIFFERENTIAL
1.5V
t
DPLH
20%
80%
80%
t
DPHL
1.5V
20%
t
HL
t
LH
V
DIFF
= V
Y
- V
Z
V
DIFF
t
SKEW = |
t
PLH
- t
PHL |
|
Y
N
- Z
N |
= V
OD
|
Y
P
- Z
P |
= V
ODP
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
5V
0
Y, Z
Y, Z
0
1.5V
1.5V
V
PH
V
PL
V
OL
* + 0.5V
V
OH
* - 0.5V
2.3V
*NOTE: V
OH
AND V
OL
ARE THE OUTPUT LEVELS IN FIGURE 2 WITH
S2 AND S1 CLOSED, RESPECTIVELY.
2.3V
t
DZL(SHDN)
, t
DZL
t
DLZ
t
DZH(SHDN)
, t
DZH
t
DHZ
DE
Figure 5. Driver Propagation Delays Figure 6. Driver Enable and Disable Times
RO
V
OH
V
OL
A
+1V
B
-1V
0 DIFFERENTIAL
1.5V
t
RPHL
t
RPLH
1.5V
t
RSKEW = |
t
RPLH
- t
RPHL |
OUTPUT NORMALLY LOW
OUTPUT NORMALLY HIGH
3V
0
V
CC
RO
RO
0
1.5V 1.5V
V
OL
+ 0.5V
V
OH
- 0.5V
1.5V
1.5V
t
RZL(SHDN)
, t
RZL
t
RLZ
t
RZH(SHDN)
, t
RZH
t
RHZ
RE
Figure 7. Receiver Propagation Delays Figure 8. Receiver Enable and Disable Times