MAX3291 Datasheet, PDF (5/16 Pages) Maxim Integrated Products – RS-485/RS-422 Transceivers with Preemphasis for High-Speed, Long-Distance Communication

RS-485/RS-422 Transceivers with Preemphasis
for High-Speed, Long-Distance Communication
__________________________________________Typical Operating Characteristics
(V_CC = +5V, T_A = +25°C, unless otherwise noted.)
TYPICAL PREEMPHASIS WAVEFORM
V_Y - V_Z
2V/
div
100ns/div
PREEMPHASIS INTERVAL vs. R_PSET
(C_PSET = 0.1µF)
2500
2250
2000
1750
1500
1250
NOTE A
1000
750
500
250
0
0 100 200 300 400 500 600 700 800 900 1000
R_PSET (kΩ)
1200
1000
800
600
400
200
0
0
R_PRE AND t_PRE vs. t_BAUD
NOTE A
500
1000
1500
2000
t_BAUD (ns)
DRIVER DIFFERENTIAL
OUTPUT VOLTAGE vs. R_DIFF
4.5
STRONG
4.0
DRIVER DIFFERENTIAL
OUTPUT VOLTAGE vs. TEMPERATURE
4.25
4.00
STRONG (V_ODP)
RECEIVER PROPAGATION DELAY
vs. TEMPERATURE
60.0
C_L = 50pF
57.5
3.5
3.0
NORMAL
2.5
2.0
1.5
1.0
3.75
55.0
3.50
52.5
3.25
50.0
3.00
47.5
2.75
2.50
NORMAL (V_OD)
45.0
0.5
0
10 20 30 40 50 60 70 80 90 100
2.25
R_DIFF = 54Ω
2.00
-40 -20 0 20 40 60 80 100
42.5
40.0
-40 -20 0 20 40 60
R_DIFF (Ω)
DRIVER PROPAGATION DELAY
TEMPERATURE (°C)
TEMPERATURE (°C)
vs. TEMPERATURE
RECEIVER PROPAGATION DELAY
50.0
C_L1 = C_L2 = 50pF
47.5
80 100
45.0
42.5
2.5V/
40.0
V_A - V_B
div
37.5
5V/
35.0
RO
div
32.5
30.0
-40 -20
0 20 40 60
TEMPERATURE (°C)
80 100
20ns/div
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.
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