®
SP3490/SP3491
+3.3V Low Power Full Duplex RS-485
Transceivers with 10Mbps Data Rate
■
Full Duplex RS-485 and RS-422
Transceivers
■
Operates from a single +3.3V supply
■
Interoperable with +5.0V logic
■
Driver/Receiver Tri-state Enable
Lines (SP3491)
■
-7V to +12V Common-Mode Input
Voltage Range
■
+200mV Receiver Input Sensitivity
■
Allows up to 32 transceivers on
the serial bus
■
Compatibility with LTC490
and SN75179 (SP3490)
■
Compatibility with LTC491
and SN75180 (SP3491)
DESCRIPTION
The
SP3490
and the
SP3491
are +3.3V low power full duplex transceivers that meet the
specifications of the RS-485 and RS-422 serial protocols. These devices are pin-to-pin
compatible with the
Sipex
SP490 and SP491 devices as well as popular industry standards.
The
SP3490
and the
SP3491
feature
Sipex's
BiCMOS process, allowing low power operation
without sacrificing performance. The
SP3490
and
SP3491
meet the electrical specifications
of RS-485 and RS-422 serial protocols up to 10Mbps under load. The
SP3491
is identical to
the
SP3490
with the addition of driver and receiver tri-state enable lines.
NC 1
14 Vcc
13 NC
12 A
Vcc 1
R 2
R 2
8 A
R
11 B
R
REB 3
7 B
DE 4
6 Z
D 3
GND 4
10 Z
D 5
D
5 Y
D
GND 6
GND 7
9 Y
8 NC
SP3490
SP3491
Rev. 10/11/02
SP3490/3491 Low Power Full-Duplex RS485 Transceivers
© Copyright 2002 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
............................................................................................. +6.0V
Input Voltages
Drivers ............................................................... -0.3V to +6.0V
Receivers .........................................................................
±14V
Output Voltages
Drivers ..............................................................................
±14V
Receivers .......................................................... -0.3V to +6.0V
Storage Temperature ................................................... -65˚C to +150˚
Power Dissipation per Package
8-pin NSOIC (derate 6.90mW/
o
C above +70
o
C) ..................... 600mW
8-pin PDIP (derate 11.8mW/
o
C above +70
o
C) ...................... 1000mW
14-pin NSOIC (derate 8.33mW/
o
C above +70
o
C) ................... 700mW
14-pin PDIP (derate 14.3mW/
o
C above +70
o
C) .................... 1200mW
SPECIFICATIONS
T
AMB
= T
MIN
to T
MAX
and V
CC
= 3.3V
±
5% unless otherwise noted.
PARAMETERS
SP3490 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
SP3490 DRIVER
AC Characteristics
Maximum Data Rate
Driver Input to Output, t
PLH
Driver Input to Output, t
PHL
Differential Driver Skew
Driver Rise or Fall Time
MIN.
TYP.
MAX.
UNITS
CONDITIONS
GND
2
1.5
V
CC
V
CC
V
CC
0.2
3
Volts
Volts
Volts
Volts
Volts
Volts
Volts
µA
mA
mA
Unloaded; R =
∞ Ω;
Figure 1
With Load; R = 50Ω; (RS-422);
Figure 1
With Load; R = 27Ω; (RS-485);
Figure 1
R = 27Ω or R = 50Ω;
Figure 1
R = 27Ω or R = 50Ω;
Figure 1
2.0
0.8
+10
+250
+250
-7V < V
O
< +12V
-7V < V
O
< +12V
10
20
20
40
40
2
5
60
60
Mbps
ns
ns
ns
R=27Ω,
Figures 2 and 8
R=27Ω,
Figures 2 and 8
t
PHL
(Y) - t
PLH
(Y) , t
PHL
(Z) - t
PLH
(Z) ,
Figures 2 and 8
From 10% to 90%;
Figures 3 and 9
20
ns
SP3490 RECEIVER
DC Characteristics
Differential Input Threshold
0.2
Input Hysteresis
Output Voltage High
V
CC
-0.4
Output Voltage Low
Input Resistance
12
Input Current (A, B); V
IN
= 12V
Input Current (A, B); V
IN
= -7V
Short-Circuit Current
+0.2
25
0.4
15
1.0
-0.8
60
Volts
mV
Volts
Volts
kΩ
mA
mA
mA
-7V < V
CM
< 12V
V
CM
= 0V
I
O
= -1.5mA, V
ID
= +200mV
I
O
= +2.5mA, V
ID
= -200mV
-7V < V
CM
≤
12V
V
IN
= 12V
V
IN
= -7V
0V < V
O
< V
CC
Rev. 10/11/02
SP3490/3491 Low Power Full-Duplex RS485 Transceivers
© Copyright 2002 Sipex Corporation
2
SPECIFICATIONS
(continued)
T
AMB
= T
MIN
to T
MAX
and V
CC
= 3.3V
±
5% unless otherwise noted.
PARAMETERS
SP3490 RECEIVER
AC Characteristics
Maximum Data Rate
Receiver Input to Output, t
PLH
Receiver Input to Output, t
PHL
Differential Receiver Skew
POWER REQUIREMENTS
Supply Voltage
Supply Current
MIN.
TYP.
MAX.
UNITS
CONDITIONS
10
40
40
70
70
4
120
85
120
85
Mbps
ns
ns
ns
ns
ns
Figures 6 and 11
T
AMB
= 25
o
C, V
CC
= 3.3V,
Figures 6 and 11
Figures 6 and 11
T
AMB
= 25
o
C, V
CC
= 3.3V,
Figures 6 and 11
t
PHL
(A) - t
PLH
(A) , t
PHL
(B) - t
PLH
(B) ,
Figures 6 and 11
+3.0
1000
800
+3.6
2000
1500
Volts
µA
DE = V
CC
DE = 0
V
DM
R
S1
R
L
= 27Ω
D
V
CC
V
OD
R
V
OC
GENERATOR
(NOTE 1)
50Ω
D
OUT
C
L
= 15pF
(NOTE 2)
V
CC
V
OM
= V
OH
+ V
OL
2
1.5V
Figure 1. Driver DC Test Load Circuit
Figure 2. Driver Propagation Delay Test Circuit
S1
D
OUT
C
L
= 50pF
(NOTE 2)
GENERATOR
(NOTE 1)
C
L
= 15pF (NOTE 2)
C
L
D
GENERATOR
(NOTE 1)
50Ω
V
CC
R
L
=
60Ω
OUT
R
L
= 110Ω
50Ω
V
OM
= V
OH
+ V
OL
2
1.5V
Figure 3. Driver Differential Output Delay and
Transition Time Circuit
V
CC
R
L
= 110Ω
S1
0V OR 3V
D
C
L
= 50pF
(NOTE 2)
GENERATOR
(NOTE 1)
50Ω
OUT
Figure 4. Driver Enable and Disable Timing Circuit,
Output HIGH
OUT
C
L
= 15pF
(NOTE 2)
V
ID
GENERATOR
(NOTE 1)
R
50Ω
1.5V
0V
V
OM
= V
CC
2
Figure 5. Driver Enable and Disable Timing Circuit,
Output LOW
Figure 6. Receiver Propagation Delay Test Circuit
Rev. 10/11/02
SP3490/3491 Low Power Full-Duplex RS485 Transceivers
© Copyright 2002 Sipex Corporation
3
3V
INPUT
0V
1.5V
-1.5V
S3
1k
V
ID
R
S2
S1
V
CC
1.5V
t
PLH
V
OM
V
OL
t
PHL
V
OH
1.5V
t
PHL
V
OM
V
OH
Y OUTPUT
C
L =
15pF
(NOTE 2)
GENERATOR
(NOTE 1)
50Ω
t
PLH
V
OM
V
OM
Z OUTPUT
V
OL
V
OM
= V
OH
+ V
OL
≈
1.5V
2
Figure 7. Receiver Enable and Disable Timing Circuit
Figure 8. Driver Propagation Delay Waveforms
3V
3V
IN
1.5V
1.5V
0V
t
DPLH
t
DPHL
2.0V
90%
50%
10%
-2.0V
t
R
t
F
DE
0V
V
OH
OUTPUT
HIGH
0V
V
CC
OUTPUT
LOW
V
OL
1.5V
t
PZH
V
OM
1.5V
t
PHZ
0.25V
90%
OUT
50%
10%
t
PZL
V
OM
t
PLZ
0.25V
V
OM
= V
OH
+ V
OL
≈
1.5V
2
Figure 9. Driver Differential Output Delay and
Transition Time Waveforms
Figure 10. Driver Enable and Disable Timing Waveforms
3V
INPUT
0V
t
RPLH
V
CC
OUTPUT
0V
V
OM
= V
CC
2
V
OM
V
OM
t
RPHL
1.5V
1.5V
Figure 11. Receiver Propagation Delay Waveforms
Rev. 10/11/02
SP3490/3491 Low Power Full-Duplex RS485 Transceivers
© Copyright 2002 Sipex Corporation
4
SPECIFICATIONS
T
AMB
= T
MIN
to T
MAX
and V
CC
= +3.3V
±
5% unless otherwise noted.
PARAMETERS
SP3491 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
SP3491 DRIVER
AC Characteristics
Maximum Data Rate
Driver Input to Output, t
PLH
Driver Input to Output, t
PHL
Differential Driver Skew
Driver Rise or Fall Time
Driver Enable to Output HIGH
Driver Enable to Output LOW
Driver Disable from LOW
Driver Disable from HIGH
MIN.
TYP.
MAX.
UNITS
CONDITIONS
GND
2
1.5
V
CC
V
CC
V
CC
0.2
3
Volts
Volts
Volts
Volts
Volts
Volts
Volts
µA
mA
mA
Unloaded; R =
∞;
Figure 1
With Load; R = 50Ω; (RS-422);
Figure 1
With Load; R = 27Ω; (RS-485);
Figure 1
R = 27Ω or R = 50Ω;
Figure 1
R = 27Ω or R = 50Ω;
Figure 1
Applies to D, REB, DE
Applies to D, REB, DE
Applies to D, REB, DE
-7V < V
O
< +12V
-7V < V
O
< +12V
2.0
0.8
+10
+250
+250
10
20
20
40
40
2
5
52
60
40
60
60
60
Mbps
ns
ns
ns
Figures 2 and 8
Figures 2 and 8
t
PHL
(Y) - t
PLH
(Y) , t
PHL
(Z) - t
PLH
(Z) ,
Figures 2 and 8
From 10% to 90%;
Figures 3 and 9
20
120
120
120
120
ns
ns
ns
ns
ns
Figures 4 and 10
Figures 5 and 10
Figures 5 and 10
Figures 4 and 10
NOTE 1:
The input pulse is supplied by a generator with the following characteristics:
PRR=250KHz, 50% duty cycle, t
r
< 6.0ns, Z
0
=50Ω.
NOTE 2:
C
L
includes probe and stray capacitance.
Rev. 10/11/02
SP3490/3491 Low Power Full-Duplex RS485 Transceivers
© Copyright 2002 Sipex Corporation
5
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