®
Preliminary SP1490E/SP1491E
Full Duplex RS-485 Transceivers
FEATURES
■
+5V Only
■
Low Power BiCMOS
■
Driver/Receiver Enable (SP1491E)
■
RS-485 and RS-422 Drivers/Receivers
■
Pin Compatible with SN75179
(SP1490E)
■
Pin Compatible with SN75180
(SP1491E)
■
Improved ESD Specifications
±15kV
Human Body Model
±15kV
IEC1000-4-2 Air Discharge
±8kV
IEC1000-4-2 Contact Discharge
VCC
1
RO
2
DI
3
GND
4
8
A
SP1490E
8 Pin - nSOIC
7
B
6
5
Z
Y
APPLICATIONS
■
Industial Networks
■
Telecom
■
Motor Control
■
HVAC/ Building Control
DESCRIPTION
The
SP1490E
is a low power differential line driver/receiver meeting RS-485 and RS-422
standards up to 20Mbps. The
SP1491E
is identical to the
SP1490E
with the addition of driver
and receiver tri-state enable lines. Both products feature
±200mV
receiver input sensitivity,
over wide common mode range. The
SP1490E
is available in 8-pin plastic DIP and 8-pin
NSOIC packages for operation over the commercial and industrial temperature ranges. The
SP1491E
is available in 14-pin DIP and 14-pin NSOIC packages for operation over the
commercial and industrial temperature ranges.
BLOCK DIAGRAM
NC 1
Vcc 1
RO 2
8 A
14 Vcc
13 NC
12 A
R
RO 2
7 B
REB 3
6 Z
DE 4
R
11 B
DI 3
GND 4
D
5 Y
DI 5
GND 6
GND 7
10 Z
D
9 Y
8 NC
SP1490E
SP1491E
Date: 5/18/04
SP1490E/1491E Full Duplex RS-485 Transceivers
© Copyright 2004 Sipex Corporation
1
ABSOLUTE MAXIMUM RATINGS
These are stress ratings only and functional operation of the device at
these ratings or any other above those indicated in the operation sections
of the specifications below is not implied. Exposure to absolute maximum
rating conditions for extended periods of time may affect reliability.
V
CC
...................................................................................................+7V
Input Voltages
Drivers................................................-0.5V to (V
CC
+0.5V)
Receivers..................................................................±14V
Output Voltages
Drivers......................................................................±14V
Receivers...........................................-0.5V to (V
CC
+0.5V)
Storage Temperature....................................................-65˚C to +150˚
Power Dissipation.....................................................................1000mW
ELECTRICAL CHARACTERISTICS
T
MIN
to T
MAX
and V
CC
= 5V
±
5% unless otherwise noted.
PARAMETERS
SP1490E/1491E DRIVER
DC Characteristics
Differential Output Voltage
Differential Output Voltage
Differential Output Voltage
Change in Magnitude of Driver
Differential Output Voltage for
Complimentary States
Driver Common-Mode
Output Voltage
Input High Voltage
Input Low Voltage
Input Current
Driver Short-Circuit Current
V
OUT
= HIGH
V
OUT
= LOW
SP1490E/1491E DRIVER
AC Characteristics
Maximum Data Rate
Driver Input to Output
Driver Input to Output
Driver Skew
Driver Rise or Fall Time
SP1491E only
Driver Enable to Output High
Driver Enable to Output Low
Driver Disable Time from Low
Driver Disable Time from High
MIN.
TYP.
MAX.
UNITS
CONDITIONS
3.5
2
1.5
V
CC
V
CC
V
CC
0.2
3
Volts
Volts
Volts
Volts
Volts
Volts
Volts
µA
mA
mA
Unloaded; R =
∞
;
see figure 1
With Load; R = 50Ω; (RS422);
see figure 1
With Load; R = 27Ω; (RS485);
see figure 1
R = 27Ω or R = 50Ω;
see figure 1
R = 27Ω or R = 50Ω;
see figure 1
Applies to D
Applies to D
Applies to D
-7V
≤
V
O
≤
+12V
-7V
≤
V
O
≤
+12V
2.0
0.8
±10
±250
±250
20
30
30
40
40
5
8
20
Mbps
ns
ns
ns
ns
t
R/F
; R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF;
see figures 3 and 6
t
R/F
; R
DIFF
= 54Ω, C
L1
= C
L2
= 100pF;
see figures 3 and 6
see figures 3 and 6,
t
R/F
= | t
DPLH
- t
DPHL
|
From 10% to 90%; R
DIFF
= 54Ω,
C
L1
= C
L2
= 100pF;
see figures 3 and 6
t
R/F
C
L1
= C
L2
= 100pF;
see figures
4 and 7;
S
2
closed
C
L1
= C
L2
= 100pF;
see figures
4 and 7;
S
1
closed
C
L1
= C
L2
= 100pF;
see figures
4 and 7;
S
1
closed
C
L1
= C
L2
= 100pF;
see figures
4 and 7;
S
2
closed
20
40
40
40
70
70
70
70
ns
ns
ns
ns
Date: 5/18/04
SP1490E/1491E Full Duplex RS-485 Transceivers
© Copyright 2004 Sipex Corporation
2
SPECIFICATIONS
(continued)
T
MIN
to T
MAX
and V
CC
= 5V
±
5% unless otherwise noted.
SP1490E/1491E RECEIVER
DC Characteristics
Differential Input Threshold
Input Hysteresis
Output Voltage High
Output Voltage Low
Input Resistance
Input Current (A, B); V
IN
= 12V
Input Current (A, B); V
IN
= -7V
Short-Circuit Current
0.2
70
3.5
+0.2
0.4
12
15
±1.0
-0.8
85
Volts
mV
Volts
Volts
kΩ
mA
mA
mA
-7V
≤
V
CM
≤
12V
V
CM
= 0V
I
O
= -4mA, V
ID
= +200mV
I
O
= +4mA, V
ID
= -200mV
-7V
≤
V
CM
≤
12V (1 unit load)
V
IN
= 12V
V
IN
= -7V
0V
≤
V
O
≤
V
CC
PARAMETERS
SP1490E/1491E RECEIVER
AC Characteristics
Maximum Data Rate
Receiver Input to Output
Receiver Input to Output
Diff. Receiver Skew It
PLH
-t
PHL
I
Receiver Tplh/Tphl
POWER REQUIREMENTS
Supply Voltage
Supply Current
ENVIRONMENTAL AND
MECHANICAL
Operating Temperature
Commercial (_C_)
Industrial (_E_)
Storage Temperature
Package
Plastic DIP (_S_)
NSOIC (_N)
A
R
V
OD
R
B
V
OC
MIN.
TYP.
MAX.
UNITS
CONDITIONS
20
20
20
45
45
5
40
50
50
10
70
Mbps
ns
ns
ns
ns
t
PLH
; R
DIFF
= 54Ω,
C
L1
= C
L2
= 100pF;
Figures 3 & 8
t
PHL
; R
DIFF
= 54Ω,
C
L1
= C
L2 =
100pF;
Figures 3 & 8
R
DIFF
= 54Ω; C
L1
= C
L2
= 100pF;
+4.75
900
+5.25
Volts
µA
0
-40
-65
+70
+85
+150
°C
°C
°C
Receiver
Output
C
RL
Test Point
S
1
1K
S
2
1K
V
CC
Figure 1. Driver DC Test Load Circuit
3V
DE
DI
A
B
C
L2
R
DIFF
C
L1
A
RO
B
15pF
Figure 2. Receiver Timing Test Load Circuit
Output
Under
Test
500
C
L
S
1
V
CC
S
2
Figure 3. Driver/Receiver Timing Test Circuit
Figure 4. Driver Timing Test Load #2 Circuit
Date: 5/18/04
SP1490E/1491E Full Duplex RS-485 Transceivers
© Copyright 2004 Sipex Corporation
3
+3V
DI
0V
DRIVER
OUTPUT
B
A
f = 1MHz; t
R
< 10ns; t
F
< 10ns
1.5V
t
PLH
V
O
1/2V
O
t
DPLH
t
DPHL
t
PHL
1/2V
O
1.5V
DIFFERENTIAL V
O
+
OUTPUT 0V
V
A
– V
B
V
O
–
t
SKEW =
| t
DPLH -
t
DPHL
|
Figure 6. Driver Propagation Delays
t
R
t
F
+3V
DE
0V
5V
A, B
V
OL
V
OH
A, B
0V
f = 1MHz; t
R
< 10ns; t
F
< 10ns
1.5V
t
ZL
2.3V
Output normally LOW
1.5V
t
LZ
0.5V
0.5V
t
HZ
2.3V
t
ZH
Output normally HIGH
Figure 7. Driver Enable and Disable Times SP1491E only
V
0D2
+
A–B
V
0D2
–
V
OH
R
V
OL
t
PHL
0V
INPUT
0V
1.5V
OUTPUT
1.5V
t
PLH
f = 1MHz; t
R
< 10ns; t
F
< 10ns
t
SKEW =
| t
PHL -
t
PLH
|
Figure 8. Receiver Propagation Delays
Date: 5/18/04
SP1490E/1491E Full Duplex RS-485 Transceivers
© Copyright 2004 Sipex Corporation
4
DETAILED DESCRIPTION
The
SP1490E
and
SP1491E
are full-duplex dif-
ferential transceivers that meet the requirements
of RS-485 and RS-422. Fabricated with a
Sipex
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 receivers
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 accommodate
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...
The receivers for both the
SP1490E
and
SP1491E
have differential inputs with an input
sensitivity as low as
±200mV.
Input impedance
of the receivers is typically 15KΩ (12KΩ mini-
mum). A wide common mode range of -7V to
+12V allows for large ground potential differ-
ences 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 floating.
The receiver of the
SP1491E
has a receiver
enable control line which is active low. A logic
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
DE
SP1491E only
1
1
0
OUTPUTS
INPUTS
OUTPUTS
DI
1
0
x
Y
1
0
z
Z
0
1
z
RE
SP1491E
only
0
0
0
1
A-B
R
Transmit Function Truth Table
+0.2V
-0.2V
open
x
1
0
1
z
Recieve Function Truth Table
Date: 5/18/04
SP1490E/1491E Full Duplex RS-485 Transceivers
© Copyright 2004 Sipex Corporation
5
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