1
Rev. 10/11/02 SP3490/3491 Low Power Full-Duplex RS485 Transceivers © Copyright 2002 Sipex Corporation
■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)
SP3490/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.
6
1
2
3
4
5
78
Vcc
GND
R
D
A
B
Z
Y
R
D
9
10
11
12
13
14
NC
REB
DE
GND
NC
NC
1
2
3
45
6
7
8
R
D
Vcc
GND
R
D
A
B
Z
Y
SP3490 SP3491
+3.3V Lo w Po wer Full Duple x RS-485
Transceiver s with 10Mbps Data Rate
®
Rev. 10/11/02 SP3490/3491 Low Power Full-Duplex RS485 Transceivers © Copyright 2002 Sipex Corporation
2
SPECIFICATIONS
TAMB = TMIN to TMAX and VCC = 3.3V ± 5% unless otherwise noted.
PARAMETERS MIN. TYP. MAX. UNITS CONDITIONS
SP3490 DRIVER
DC Characteristics
Differential Output Voltage GND VCC Volts Unloaded; R = ∞ Ω;
Figure 1
Differential Output Voltage 2 VCC Volts With Load; R = 50Ω; (RS-422);
Figure 1
Differential Output Voltage 1.5 VCC Volts W
ith Load; R = 27
Ω
; (RS-485);
Figure 1
Change in Magnitude of Driver
Differential Output Voltage for
Complimentary States 0.2 Volts R = 27Ω or R = 50Ω;
Figure 1
Driver Common-Mode
Output Voltage 3 Volts R = 27Ω or R = 50Ω;
Figure 1
Input High Voltage 2.0 Volts
Input Low Voltage 0.8 Volts
Input Current +10 µA
Driver Short-Circuit Current
VOUT = HIGH +250 mA -7V < VO < +12V
VOUT = LOW +250 mA -7V < VO < +12V
SP3490 DRIVER
AC Characteristics
Maximum Data Rate 10 Mbps
Driver Input to Output, tPLH 20 40 60 ns R=27Ω,
Figures 2 and 8
Driver Input to Output, tPHL 20 40 60 ns R=27Ω,
Figures 2 and 8
Differential Driver Skew 2 ns tPHL(Y) - tPLH(Y) , tPHL(Z) - tPLH(Z) ,
Figures 2 and 8
Driver Rise or Fall Time 5 20 ns From 10% to 90%;
Figures 3 and 9
SP3490
RECEIVER
DC Characteristics
Differential Input Threshold 0.2 +0.2 Volts -7V < VCM < 12V
Input Hysteresis 25 mV VCM = 0V
Output Voltage High VCC-0.4 Volts IO = -1.5mA, VID = +200mV
Output Voltage Low 0.4 Volts IO = +2.5mA, VID = -200mV
Input Resistance 12 15 kΩ-7V < VCM ≤ 12V
Input Current (A, B); VIN = 12V 1.0 mA VIN = 12V
Input Current (A, B); VIN = -7V -0.8 mA VIN = -7V
Short-Circuit Current 60 mA 0V < VO < VCC
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.
VCC ............................................................................................. +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/oC above +70oC) ..................... 600mW
8-pin PDIP (derate 11.8mW/oC above +70oC) ...................... 1000mW
14-pin NSOIC (derate 8.33mW/oC above +70oC) ................... 700mW
14-pin PDIP (derate 14.3mW/oC above +70oC) .................... 1200mW
3
Rev. 10/11/02 SP3490/3491 Low Power Full-Duplex RS485 Transceivers © Copyright 2002 Sipex Corporation
SPECIFICATIONS (continued)
TAMB = TMIN to TMAX and VCC = 3.3V ± 5% unless otherwise noted.
PARAMETERS MIN. TYP. MAX. UNITS CONDITIONS
SP3490 RECEIVER
AC Characteristics
Maximum Data Rate 10 Mbps
Receiver Input to Output, tPLH 40 70 120 ns
Figures 6 and 11
85 ns TAMB = 25oC, VCC = 3.3V,
Figures 6 and 11
Receiver Input to Output, tPHL 40 70 120 ns
Figures 6 and 11
85 ns TAMB = 25oC, VCC = 3.3V,
Figures 6 and 11
Differential Receiver Skew 4 ns tPHL(A) - tPLH(A) , tPHL(B) - tPLH(B) ,
Figures 6 and 11
POWER REQUIREMENTS
Supply Voltage +3.0 +3.6 Volts
Supply Current 1000 2000 µADE = VCC
800 1500 DE = 0
Figure 4. Driver Enable and Disable Timing Circuit,
Output HIGH
Figure 5. Driver Enable and Disable Timing Circuit,
Output LOW
Figure 1. Driver DC Test Load Circuit Figure 2. Driver Propagation Delay Test Circuit
GENERATOR
(NOTE 1) 50Ω
V
CC
S1
V
DM
R
L
= 27Ω
OUT
C
L
= 15pF
(NOTE 2)
V
OM
= 1.5V
V
OH
+ V
OL
2
D
GENERATOR
(NOTE 1) 50Ω
S1
R
L
= 110Ω
OUT
C
L
= 50pF
(NOTE 2)
V
OM
= 1.5V
V
OH
+ V
OL
2
D
GENERATOR
(NOTE 1) 50Ω
S1 R
L
= 110Ω
OUT
C
L
= 50pF
(NOTE 2)
D
0V OR 3V
V
CC
R
RV
OC
D
V
CC
V
OD
Figure 6. Receiver Propagation Delay Test Circuit
GENERATOR
(NOTE 1)
50Ω
1.5V
0V
V
ID
ROUT
C
L
= 15pF
(NOTE 2)
V
OM
= V
CC
2
GENERATOR
(NOTE 1) 50Ω
C
L
OUT
D
V
CC
R
L
=
60Ω
C
L
= 15pF (NOTE 2)
Figure 3. Driver Differential Output Delay and
Transition Time Circuit
Rev. 10/11/02 SP3490/3491 Low Power Full-Duplex RS485 Transceivers © Copyright 2002 Sipex Corporation
4
Figure 7. Receiver Enable and Disable Timing Circuit Figure 8. Driver Propagation Delay Waveforms
Figure 9. Driver Differential Output Delay and
Transition Time Waveforms Figure 10. Driver Enable and Disable Timing Waveforms
Figure 11. Receiver Propagation Delay Waveforms
1.5V
-1.5V
S3
V
ID
GENERATOR
(NOTE 1)
50Ω
C
L =
15pF
(NOTE 2)
R
1k
S1
S2
V
CC
0V
V
OH
t
PLH
t
PHL
V
OM
t
PHL
t
PLH
3V
V
OL
V
OH
1.5V 1.5V
INPUT
Y OUTPUT
V
OM
Z OUTPUT
V
OL
V
OM
V
OM
V
OM
= V
OH
+ V
OL
2≈ 1.5V
3V
0V
V
CC
t
RPLH
1.5V
t
RPHL
V
OM
V
OM
0V
1.5V
INPUT
OUTPUT
V
OM
= V
CC
2
IN 1.5V
t
DPLH
1.5V
t
DPHL
3V
0V
OUT 50% 50%
10% 10%
90% 90%
t
R
t
F
2.0V
-2.0V
0V
VOH tPZH
0.25V
tPHZ
VOM
tPZL tPLZ
3V
VOL
VCC
1.5V 1.5V
DE
OUTPUT
HIGH
VOM 0.25V
0V
OUTPUT
LOW
VOM = VOH + VOL
2≈ 1.5V
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Rev. 10/11/02 SP3490/3491 Low Power Full-Duplex RS485 Transceivers © Copyright 2002 Sipex Corporation
SPECIFICATIONS
TAMB = TMIN to TMAX and VCC = +3.3V ± 5% unless otherwise noted.
PARAMETERS MIN. TYP. MAX. UNITS CONDITIONS
SP3491 DRIVER
DC Characteristics
Differential Output Voltage GND VCC Volts Unloaded; R = ∞;
Figure 1
Differential Output Voltage 2 VCC Volts With Load; R = 50Ω; (RS-422);
Figure 1
Differential Output Voltage 1.5 VCC Volts
With Load; R = 27Ω; (RS-485);
Figure 1
Change in Magnitude of Driver
Differential Output Voltage for
Complimentary States 0.2 Volts R = 27
Ω
or R = 50
Ω
;
Figure 1
Driver Common-Mode
Output Voltage 3 Volts R = 27
Ω
or R = 50
Ω
;
Figure 1
Input HIGH Voltage 2.0 Volts Applies to D, REB, DE
Input LOW Voltage 0.8 Volts Applies to D, REB, DE
Input Current +10 µAApplies to D, REB, DE
Driver Short-Circuit Current
VOUT = HIGH +250 mA -7V < VO < +12V
VOUT = LOW +250 mA -7V < VO < +12V
SP3491 DRIVER
AC Characteristics
Maximum Data Rate 10 Mbps
Driver Input to Output, tPLH 20 40 60 ns
Figures 2 and 8
Driver Input to Output, tPHL 20 40 60 ns
Figures 2 and 8
Differential Driver Skew 2 ns tPHL(Y) - tPLH(Y) , tPHL(Z) - tPLH(Z) ,
Figures 2 and 8
Driver Rise or Fall Time 5 20 ns From 10% to 90%;
Figures 3 and 9
Driver Enable to Output HIGH 52 120 ns
Figures 4 and 10
Driver Enable to Output LOW 60 120 ns
Figures 5 and 10
Driver Disable from LOW 40 120 ns
Figures 5 and 10
Driver Disable from HIGH
60 120 ns
Figures 4 and 10
NOTE 1: The input pulse is supplied by a generator with the following characteristics:
PRR=250KHz, 50% duty cycle, tr < 6.0ns, Z0=50Ω.
NOTE 2: CL includes probe and stray capacitance.
Rev. 10/11/02 SP3490/3491 Low Power Full-Duplex RS485 Transceivers © Copyright 2002 Sipex Corporation
6
Receiver Disable from HIGH
65 200 ns
Figures 7 and 12;
S2 closed, S1 open
POWER REQUIREMENTS
Supply Voltage +3.0 +3.6 Volts
Supply Current 1000 2000 µAREB, D = 0V or VCC; DE = VCC
800 1500 µADE=0V
SPECIFICATIONS (continued)
TAMB = TMIN to TMAX and VCC = +3.3V ± 5% unless otherwise noted.
PARAMETERS MIN. TYP. MAX. UNITS CONDITIONS
SP3491
RECEIVER
DC Characteristics
Differential Input Threshold -0.2 +0.2 Volts -7V < VCM < 12V
Input Hysteresis 25 mV VCM = 0V
Output Voltage HIGH VCC-0.4 Volts IO = -1.5mA, VID = +200mV
Output Voltage LOW 0.4 Volts IO = +2.5mA, VID = -200mV
Three State (high impedance)
Output Current +1 µA 0V < VO < VCC; REB = VCC
Input Resistance 12 15 kΩ-7V < VCM < 12V
Input Current (A, B); VIN = 12V 1.0 mA DE = 0V, VCC = 0V or +3.6V, VIN = 12V
Input Current (A, B); VIN = -7V -0.8 mA DE = 0V, VCC = 0V or +3.6V, VIN = -7V
Short-Circuit Current 60 mA 0V < VO < VCC
SP3491
RECEIVER
AC Characteristics
Maximum Data Rate 10 Mbps REB = 0V, DE = VCC
Receiver Input to Output, tPLH 40 70 120 ns
Figures 6 & 11
85 ns TAMB = +25oC, VCC = +3.3V,
Figures 6 and 11
Receiver Input to Output, tPHL 40 70 120 ns
Figures 6 & 11
85 ns TAMB = +25oC, VCC = +3.3V,
Figures 6 and 11
Differential Receiver Skew 4 ns tPHL(A) - tPLH(A) , tPHL(B) - tPLH(B) ,
Figures 6 & 11
Receiver Enable to Output LOW
65 150 ns
Figures 7 and 12;
S1 closed, S2 open
Receiver Enable to Output HIGH
65 150 ns
Figures 7 and 12;
S2 closed, S1 open
Receiver Disable from LOW
65 200 ns
Figures 7 and 12;
S1 closed, S2 open
Figure 12. Receiver Enable and Disable Waveforms
3V
0V tPRLZ
1.5V
tPRZL
tPRSL
1.5V
1.5V
10%
VCC
REB
OUTPUT
S1 is closed
S2 is open
S3 = -1.5V
VOL
3V
0V t
PRHZ
1.5V
t
PRZH
t
PRSH
1.5V
1.5V
10%
0V
V
OH
REB
OUTPUT
S1 is open
S2 is closed
S3 = 1.5V
7
Rev. 10/11/02 SP3490/3491 Low Power Full-Duplex RS485 Transceivers © Copyright 2002 Sipex Corporation
Figure 14. Pinout for the SP3491
Figure 13. Pinout for the SP3490
PIN FUNCTION - SP3490
Pin 1 - VCC - Positive supply +3.00 < VCC < +3.60
Pin 2 - R - Receiver output.
Pin 3 - D - Driver input.
Pin 4 - GND - Ground connection.
Pin 5 - Y - Non-inverting driver output.
Pin 6 - Z - Inverting driver output.
Pin 7 - B - Inverting receiver input.
Pin 8 - A - Non-inverting receiver input.
PIN FUNCTION - SP3491
Pin 1 - NC - No connect.
Pin 2 - R - Receiver output.
Pin 3 - REB - Receiver output enable active LOW.
Pin 4 - DE - Driver output enable active HIGH.
Pin 5 - D - Driver input.
Pin 6 - GND - Ground connection.
Pin 7 - GND - Ground connection.
Pin 8 - NC - No connect.
Pin 9 - Y - Non-inverting driver output.
Pin 10 - Z - Inverting driver output.
Pin 11 - B - Inverting receiver input.
Pin 12 - A - Non-inverting receiver input.
Pin 13 - NC - No connect.
Pin 14 - VCC - Positive supply +3.00 < VCC< +3.60
6
1
2
3
4
5
78
Vcc
GND
R
D
A
B
Z
Y
R
D
9
10
11
12
13
14
NC
REB
DE
GND
NC
NC
1
2
3
45
6
7
8
R
D
Vcc
GND
R
D
A
B
Z
Y
Rev. 10/11/02 SP3490/3491 Low Power Full-Duplex RS485 Transceivers © Copyright 2002 Sipex Corporation
8
DESCRIPTION
The SP3490 and the SP3491 are two members
in the family of +3.3V low power full duplex
transceivers that meet the electrical specifications
of the RS-485 and RS-422 serial protocols.
These devices are pin-to-pin compatible with
the Sipex SP490 and the 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.
Driver
The drivers for both the SP3490 and SP3491
have differential outputs. The typical voltage
output swing with no load will be 0 volts to VCC.
With a load of 54Ω across the differential
outputs, the driver maintains greater than 1.5V
voltage levels.
The driver of the SP3491 has a driver enable
control line which is active high. A logic high on
DE (pin 4) of the SP3491 will enable the differ-
ential driver outputs. A logic low on DE (pin 4)
of the SP3491 will tri-state the driver outputs.
The SP3490 does not have a driver enable.
Receiver
The receivers for the SP3490 and SP3491 have
differential inputs with an input sensitivity
as low as ±100mV. 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
SP3490 and SP3491 are equipped with a
fail-safe feature that guarantees the receiver
output will be in a high state when the input
is left unconnected.
The receiver of the SP3491 has a receiver enable
control line which is active low. A logic low on
REB (pin 3) of the SP3491 will enable the
differential receiver. A logic high on REB
(pin 3) of the SP3491 will tri-state the receiver.
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Rev. 10/11/02 SP3490/3491 Low Power Full-Duplex RS485 Transceivers © Copyright 2002 Sipex Corporation
D
ALTERNATE
END PINS
(BOTH ENDS)
D1 = 0.005" min.
(0.127 min.)
E
PACKAGE: PLASTIC
DUAL–IN–LINE
(NARROW)
DIMENSIONS (Inches)
Minimum/Maximum
(mm)
A = 0.210" max.
(5.334 max).
E1
C
Ø
LA2
A1 = 0.015" min.
(0.381min.)
B
B1
e = 0.100 BSC
(2.540 BSC) eA = 0.300 BSC
(7.620 BSC)
A2
B
B1
C
D
E
E1
L
Ø
0.115/0.195
(2.921/4.953)
0.014/0.022
(0.356/0.559)
0.045/0.070
(1.143/1.778)
0.008/0.014
(0.203/0.356)
0.735/0.775
(18.669/19.685)
0.300/0.325
(7.620/8.255)
0.240/0.280
(6.096/7.112)
0.115/0.150
(2.921/3.810)
0°/ 15°
(0°/15°)
0.115/0.195
(2.921/4.953)
0.014/0.022
(0.356/0.559)
0.045/0.070
(1.143/1.778)
0.008/0.014
(0.203/0.356)
0.355/0.400
(9.017/10.160)
0.300/0.325
(7.620/8.255)
0.240/0.280
(6.096/7.112)
0.115/0.150
(2.921/3.810)
0°/ 15°
(0°/15°)
8–PIN 14–PIN
Rev. 10/11/02 SP3490/3491 Low Power Full-Duplex RS485 Transceivers © Copyright 2002 Sipex Corporation
10
D
EH
PACKAGE: PLASTIC
SMALL OUTLINE (SOIC)
(NARROW)
DIMENSIONS (Inches)
Minimum/Maximum
(mm) 8–PIN
A
A1
Ø
L
Be
h x 45°
A
A1
B
D
E
e
H
h
L
Ø
0.053/0.069
(1.346/1.748)
0.004/0.010
(0.102/0.249
0.014/0.019
(0.35/0.49)
0.189/0.197
(4.80/5.00)
0.150/0.157
(3.802/3.988)
0.050 BSC
(1.270 BSC)
0.228/0.244
(5.801/6.198)
0.010/0.020
(0.254/0.498)
0.016/0.050
(0.406/1.270)
0°/8°
(0°/8°)
14–PIN
0.053/0.069
(1.346/1.748)
0.004/0.010
(0.102/0.249)
0.013/0.020
(0.330/0.508)
0.337/0.344
(8.552/8.748)
0.150/0.157
(3.802/3.988)
0.050 BSC
(1.270 BSC)
0.228/0.244
(5.801/6.198)
0.010/0.020
(0.254/0.498)
0.016/0.050
(0.406/1.270)
0°/8°
(0°/8°)
11
Rev. 10/11/02 SP3490/3491 Low Power Full-Duplex RS485 Transceivers © Copyright 2002 Sipex Corporation
ORDERING INFORMATION
Model Temperature Range Package
SP3490CN 0˚C to +70˚C 8-Pin NSOIC
SP3490CP 0˚C to +70˚C 8-Pin DIP
SP3490EN -40˚C to +85˚C 8-Pin NSOIC
SP3490EP -40˚C to +85˚C 8-Pin DIP
SP3491CN 0˚C to +70˚C 14-Pin NSOIC
SP3491CP 0˚C to +70˚C 14-Pin DIP
SP3491EN. -40˚C to +85˚C 14-Pin NSOIC
SP3491EP -40˚C to +85˚C 14-Pin DIP
Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the
application or use of any product or circuit described hereing; neither does it convey any license under its patent rights nor the rights of others.
Please consult the factory for pricing and availability on a Tape-On-Reel option.
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Corporation
Sipex Corporation
Headquarters and
Sales Office
233 South Hillview Drive
Milpitas, CA 95035
TEL: (408) 934-7500
FAX: (408) 935-7600
Sales Office
22 Linnell Circle
Billerica, MA 01821
TEL: (978) 667-8700
FAX: (978) 670-9001
e-mail: sales@sipex.com
