Datasheet

MAX3291/MAX3292
RS-485/RS-422 Transceivers with Preemphasis
for High-Speed, Long-Distance Communication
_______________________________________________________________________________________ 5
TYPICAL PREEMPHASIS WAVEFORM
MAX3291/2-01
100ns/div
V
Y
- V
Z
2V/
div
2500
0
0 1000
PREEMPHASIS INTERVAL vs. R
PSET
(C
PSET
= 0.1µF)
250
500
2250
MAX3291/2-02
R
PSET
(kΩ)
PREEMPHASIS INTERVAL (ns)
200100 300 400 600500
800
700 900
2000
1750
750
1500
1250
1000
NOTE A
0
400
200
800
NOTE A
600
1000
1200
0 1000500 1500 2000
R
PRE
AND t
PRE
vs. t
BAUD
MAX3291/92 toc 03
t
BAUD
(ns)
R
PRE
(kΩ)
0
1.0
0.5
2.0
1.5
2.5
3.0
4.0
3.5
4.5
10 30 40 5020 60 70 80 90
100
DRIVER DIFFERENTIAL
OUTPUT VOLTAGE vs. R
DIFF
MAX3291/2-04
R
DIFF
(Ω)
DRIVER DIFFERENTIAL OUTPUT VOLTAGE (V)
STRONG
NORMAL
30.0
35.0
32.5
40.0
37.5
42.5
47.5
45.0
50.0
-40 0 20-20 40 60 80
100
DRIVER PROPAGATION DELAY
vs. TEMPERATURE
MAX3291/2-07
TEMPERATURE (°C)
PROPAGATION DELAY (ns)
C
L1
= C
L2
= 50pF
2.00
2.50
2.25
3.00
2.75
3.25
3.50
4.00
3.75
4.25
-40 0 20-20 40 60 80
100
DRIVER DIFFERENTIAL
OUTPUT VOLTAGE vs. TEMPERATURE
MAX3291/2-05
TEMPERATURE (°C)
DIFFERENTIAL OUTPUT VOLTAGE (V)
STRONG (V
ODP
)
R
DIFF
= 54Ω
NORMAL (V
OD
)
40.0
45.0
42.5
50.0
47.5
52.5
57.5
55.0
60.0
-40 0 20-20 40 60 80
100
RECEIVER PROPAGATION DELAY
vs. TEMPERATURE
MAX3291/2-06
TEMPERATURE (°C)
PROPAGATION DELAY (ns)
C
L
= 50pF
RECEIVER PROPAGATION DELAY
MAX3291/2-08
20ns/div
V
A
- V
B
RO
2.5V/
div
5V/
div
__________________________________________Typical Operating Characteristics
(V
CC
= +5V, T
A
= +25°C, unless otherwise noted.)
Note A: Dotted line represents region in which preemphasis may not work in systems with excessive power-supply noise. See
Preemphasis at Low Data Rates .