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SP1491ECN-L/TR

P1-P3P4-P6P7-P8
4
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 510-668-7017 • www.exar.com SP1490_SP1491E_101_052413
Figure 6. Driver Propagation Delays
+3V
0V
DE
5V
V
OL
A, B
0V
1.5V 1.5V
t
ZL
t
ZH
f = 1MHz; t
R
< 10ns; t
F
< 10ns
V
OH
A, B
2.3V
2.3V
t
LZ
t
HZ
0.5V
0.5V
Output normally LOW
Output normally HIGH
Figure 7. Driver Enable and Disable Times SP1491E only
Figure 8. Receiver Propagation Delays
+3V
0V
DI
B
A
DRIVER
OUTPUT
V
O
+
DIFFERENTIAL
OUTPUT
V
A
– V
B
0V
V
O
–
t
SKEW
t
SKEW
1.5V 1.5V
t
PLH
t
PLH
t
R
t
F
f = 1MHz; t
R
< 10ns; t
F
< 10ns
V
O
1/2V
O
1/2V
O
t
PHL
V
OH
V
OL
R
1.5V 1.5V
t
PHL
f = 1MHz; t
R
10ns; t
F
10ns
OUTPUT
V
0D2
+
V
0D2
–
A – B
0V 0V
t
PHL
INPUT
5
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 510-668-7017 • www.exar.com SP1490_SP1491E_101_052413
TheSP1490EandSP1491Earefull-duplexdif-
ferentialtransceiversthatmeettherequirements
ofRS-485andRS-422.FabricatedwithaExar
proprietary BiCMOS process, both products
requireafractionofthepowerofolderbipolar
designs.
The RS-485 standard is ideal for multi-drop
applications or for long-distance interfaces.
RS-485allowsupto32driversand32receiv-
ers to be connected to a data bus, making it
an ideal choice for multi-drop applications.
Sincethecablingcanbeaslongas4,000feet,
RS-485transceiversareequippedwithawide
(-7Vto+12V)commonmoderangetoaccom-
modate ground potential differences. Because
RS-485isadifferentialinterface,dataisvirtually
immunetonoiseinthetransmissionline.
Driver...
ThedriversforboththeSP1490EandSP1491E
have differential outputs. The typical voltage
outputswingwithnoloadwillbe0voltsto+5
volts. With worst case loading of 54Ω across
thedifferentialoutputs,thedrivercanmaintain
greaterthan1.5Vvoltagelevels.
ThedriveroftheSP1491Ehasadriverenable
control line which is active high. A logic high
on DE (pin 4) of the SP1491E will enable
thedifferentialdriveroutputs.
A logiclow onDE(pin 4)ofthe SP1491Ewill
tri-statethedriveroutputs.TheSP1490Edoes
nothaveadriverenable.
Receiver...
ThereceiversforboththeSP1490EandSP1491E
have differential inputs with an input sensitiv-
ityas low as±200mV.Inputimpedance ofthe
receivers is typically 15KΩ (12KΩ minimum).
A wide common mode range of -7V to +12V
allows for large ground potential differences
between systems. The receivers for both the
SP1490E and SP1491E are equipped with
the fail-safe feature. Fail-safe guarantees that
thereceiveroutputwillbeinahighstatewhen
theinputisleftunconnectedandoating.
The receiver of the SP1491E has a receiver
enablecontrol linewhich isactive low.Alogic
lowonREB(pin3)oftheSP1491Ewillenable
the differential receiver. A logic high on REB
(pin 3) of the SP1491E will tri-state the re-
ceiver.
INPUTS OUTPUTS
DE
SP1491E only
DI Y Z
1
1
0
1
0
x
1
0
z
0
1
z
INPUTS OUTPUTS
RE
SP1491E
A-B R
0
0
0
1
+0.2V
-0.2V
open
x
1
0
1
z
Transmit Function Truth Table
Recieve Function Truth Table
only
DETAILED DESCRIPTION
6
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 510-668-7017 • www.exar.com SP1490_SP1491E_101_052413
PACKAGE: 8 PIN NSOIC
P1-P3P4-P6P7-P8

SP1491ECN-L/TR

Mfr. #:
Buy SP1491ECN-L/TR
Manufacturer:
MaxLinear
Description:
RS-485 Interface IC 20MBPS FULL-DUPLEX RS485 W/+/-15KV ESD
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
Payment:
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