1
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 510-668-7017 • www.exar.com SP3483_100_010912
DESCRIPTION
• RS-485 and RS-422 Transceiver
• Operates from a single +3.3V Supply
• Interoperable with +5.0V logic
• Driver/Receiver Enable
• Low Power Shutdown mode
• -7V to +12V Common-Mode Input Voltage Range
• Allows up to 32 transceivers on the serial bus
• Compatibility with the industry standard
75176 pinout
• Driver Output Short-Circuit Protection
• Slew Rate Limited Driver for Low EMI
SP3483
+3.3V Low Power Slew Rate Limited
Half-Duplex RS-485 Transceiver
The SP3483 device is part of a family of +3.3V low power half-duplex transceivers that meet
the specications of the RS-485 and RS-422 serial protocols. This device is pin-to-pin compat-
ible with the Exar SP483 device as well as popular industry standards. The SP3483 features
Exar's BiCMOS design allowing low power operation without sacricing performance. The
SP3483 is slew rate limited to reduce EMI and can meet the requirements of the RS-485
and RS-422 protocols up to 250kbps.
TRUTH TABLES
INPUTS OUTPUTS
RE DE DI
LINE
CONDITION B A
X 1 1 No Fault 0 1
X 1 0 No Fault 1 0
X 0 X X Z Z
Table 1. Transmit Function Truth Table
INPUTS OUTPUTS
RE DE A - B R
0 0 +0.2V 1
0 0 -0.2V 0
0 0 Inputs Open 1
1 0 X Z
Table 2. Receive Function Truth Table
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Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 510-668-7017 • www.exar.com SP3483_100_010912
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 specications
below is not implied. Exposure to absolute maximum
rating conditions for extended periods of time may
affect reliability.
VCC.....................................................................+6.0V
Input Voltages
Logic....................................-0.3V to +6.0V
Drivers.................................-0.3V to +6.0V
Receivers.........................................+/-15V
Output Voltages
Drivers.............................................+/-15V
Receivers............................-0.3V to +6.0V
Storage Temperature.......................-65˚C to +150˚C
Power Dissipation
8-pin NSOIC...................................................500mW
(derate 6.14mW/ºC above +70ºC)
ELECTRICAL CHARACTERISTICS
TMIN to TMAX and VCC = +3.3V +/-5% unless otherwise noted.
PARAMETERS MIN. TYP. MAX. UNITS CONDITIONS
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 = 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 Applies to DE, DI, RE
Input Low Voltage 0.8 Volts Applies to DE, DI, RE
Input Current +/-10 µA Applies to DE, DI, RE
Driver Short Circuit Current,
VOUT = HIGH
+/-250 mA -7V ≤ VO ≤ +12V; Figure 8
Driver Short Circuit Current,
VOUT = LOW
+/-250 mA -7V ≤ VO ≤ +12V; Figure 8
DRIVER
AC Characteristics
Max. Transmission Rate 250 kbps RE = Vcc, DE = Vcc
Driver Input to Output, tPLH 400 900 1500 ns Figures 2 & 9
Driver Input to Output, tPHL 400 900 1500 ns Figures 2 & 9
Differential Driver Skew 10 ns |tDO1 - tDO2|, Figures 2 and 10,
Driver Rise or Fall Time 700 1000 ns From 10%-90%; Figures 3 and 10
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Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 510-668-7017 • www.exar.com SP3483_100_010912
PARAMETERS MIN. TYP. MAX. UNITS CONDITIONS
DRIVER (continued)
AC Characteristics
Driver Enable to Output High 700 1300 ns Figures 4 and 11,
Driver Enable to Output Low 690 1300 ns Figures 5 and 11
Driver Disable Time from High 80 120 ns Figures 5 and 11
Driver Disable Time from Low 90 120 ns Figures 4 and 11
RECEIVER
DC Characteristics
Differential Input Threshold -0.2 +0.2 Volts -7V ≤ VCM ≤ +12V
Input Hysteresis 20 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; RE = 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 7 60 mA 0V ≤ VCM ≤ VCC
RECEIVER
AC Characteristics
Max. Transmission Rate 250 kbps RE = 0V, DE = 0V
Receiver Input to Output, tRPLH 35 70 120 ns Figures 6 and 12
Receiver Input to Output, tRPHL 35 70 120 ns Figures 6 and 12
Differential Receiver Skew 50 ns |tRPHL - tRPLH|, Figures 6 and 12
Receiver Enable to Output Low 45 70 ns Figures 7 and 13; S1 Closed, S2
open
Receiver Enable to Output High 45 70 ns Figures 7 and 13; S2 Closed, S1
open
Receiver Disable from LOW 45 70 ns Figures 7 and 13; S1 Closed, S2
open
Receiver Disable from High 45 70 ns Figures 7 and 13; S2 Closed, S1
open
ELECTRICAL CHARACTERISTICS
TMIN to TMAX and VCC = +3.3V +/-5% unless otherwise noted.
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Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 510-668-7017 • www.exar.com SP3483_100_010912
PARAMETERS MIN. TYP. MAX. UNITS CONDITIONS
Shutdown Timing
Time to Shutdown 50 200 600 ns RE = 5V, DE = 0V
Driver Enable from Shutdown
to Output High
2000 ns Figures 4 and 11
Driver Enable from Shutdown
to Output Low
2000 ns Figures 5 and 11
Receiver Enable from
Shutdown to Output High
2500 ns Figures 7 and 13; S2 Closed, S1
open
Receiver Enable from
Shutdown to Output Low
2500 ns Figures 7 and 13; S1 Closed, S2
open
POWER REQUIREMENTS
Supply Current
No Load 1000 2000 µA RE, DI = 0V or VCC; DE = VCC
800 1500 µA RE = 0V, DI = 0V or 5V; DE = 0V
Shutdown Mode 10 µA DE = 0V, RE = VCC
PIN FUNCTION
Pin 1 - RO - Receiver Output
Pin 2 - RE - Receiver Output Enable Active LOW
Pin 3 - DE - Driver Output Enable Active HIGH
Pin 4 - DI - Driver Input
Pin 5 - GND - Ground Connection
Pin 6 - A - Driver Output / Receiver Input
Non-Inverting
Pin 7 - B - Driver Output / Receiver Input Inverting
Pin 8 - Vcc - Positive Supply
ELECTRICAL CHARACTERISTICS
TMIN to TMAX and VCC = +3.3V +/-5% unless otherwise noted.
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Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 510-668-7017 • www.exar.com SP3483_100_010912
TEST CIRCUITS
R
RV
OC
D
Vcc
V
OD
Figure 1. Driver DC Test Load Circuit
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.
GENERATOR
(NOTE 1) 50Ω
S1
R
L
= 110Ω
OUT
C
L
= 50pF
(NOTE 2)
V
OM
= ≈ 1.5V
V
OH
+ V
OL
2
D
Figure 4. Driver Enable and Disable Timing Circuit,
Output High
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
Figure 5. Driver Enable and Disable Timing Circuit,
Output Low
GENERATOR
(NOTE 1) 50Ω
S1
RL = 110Ω
OUT
CL = 50pF
(NOTE 2)
D
0V OR 3V
VCC
GENERATOR
(NOTE 1)
50Ω
1.5V
0V
V
ID
ROUT
C
L
= 15pF
(NOTE 2)
V
OM
= V
CC
2
Figure 6. Receiver Propagation Delay Test Circuit
1.5V
-1.5V
S3
VID
GENERATOR
(NOTE 1)
50Ω
CL
= 15pF
(NOTE 2)
R
1k
S1
S2
VCC
A/Y
D
DI = 0 or Vcc
B/Z
DE = 0 or Vcc
I
OS D
100Ω
-7V to +12V V
Figure 7. Receiver Enable and Disable Timing
Circuit
Figure 8. Driver Short Circuit Current Limit Test
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Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 510-668-7017 • www.exar.com SP3483_100_010912
Figure 9. Driver Propagation Delay Waveforms
0V
VOH
tPLH tPHL
V
OM
tPHL tPLH
3V
VOL
VOH
1.5V 1.5V
INPUT
A
OUTPUT
V
OM
B OUTPUT
VOL
V
OM
V
OM
V
OM
= V
OH
+ V
OL
2» 1.5V
SWITCHING WAVEFORMS
Figure 13. Receiver Enable and Disable Waveforms
IN 1.5V
tDO1
1.5V
tDO2
3V
0V
OUT
50% 50%
10% 10%
90% 90%
tTD tTD
2.0V
-2.0V
Figure 10. Driver Differential Output Delay and
Transition Time Waveforms
0V
VOH
tPZH
0.25V
tPHZ
V
OM
tPZL tPLZ
3V
VOL
VCC
1.5V 1.5V
DE
OUTPUT
HIGH
V
OM
0.25V
0V
OUTPUT
LOW
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
VOM = VCC
2
Figure 12. Receiver Propagation Delay WaveformsFigure 11. Driver Enable and Disable Timing
Waveforms
3V
0V
t
PRHZ
1.5V
t
PRZH
t
PRSH
1.5V
1.5V
10%
0V
V
OH
RE
OUTPUT
S1 is open
S2 is closed
S3 = 1.5V
3V
0V
t
PRLZ
1.5V
t
PRZL
t
PRSL
1.5V
1.5V
10%
V
CC
RE
OUTPUT
S1 is closed
S2 is open
S3 = -1.5V
V
OL
NOTE 1: The input pulse is supplied by a generator with the following characteristics:
PRR = 250kHz, 50% duty cycle, tR < 6.0ns, ZO = 50Ω.
NOTE 2: CL includes probe and stray capacitance.
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Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 510-668-7017 • www.exar.com SP3483_100_010912
The SP3483 device is part of a family of
+3.3V low power half-duplex transceivers
that meet the specications of the RS-485
and RS-422 serial protocols. This device is
pin-to-pin compatible with the Exar SP483
device as well as popular industry standards.
The SP3483 features Exar's BiCMOS pro-
cess allowing low power operation without
sacricing performance.
The RS-485 standard is ideal for multi-drop
applications and 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 accommodate ground potential differ-
ences. Because RS-485 is a differential
interface, data is virtually immune to noise
in the transmission line.
Drivers
The driver outputs of the SP3483 are dif-
ferential outputs meeting the RS-485 and
RS-422 standards. The typical voltage
output swing with no load will be 0 Volts to
+3.3 Volts. With worst case loading of 54Ω
across the differential outputs, the drivers
can maintain greater than 1.5V voltage
levels. The drivers have an enable control
line which is active HIGH. A logic HIGH on
DE (pin 3) will enable the differential driver
outputs. A logic LOW on the DE (pin 3) will
force the driver outputs into high impedance
(high-Z).
The SP3483 has internally slew rate lim-
ited driver outputs to minimize EMI. The
transceivers will operate up to 250kbps.
The 250mA ISC maximum limit on the driver
output allows the SP3483 to withstand an
innite short circuit over the -7.0V to +12V
common mode range without catastrophic
damage to the IC.
Receivers
The SP3483 receiver has differential inputs
with an input sensitivity 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 sys-
tems. The receiver of the SP3483 has a tri-
state enable control input RE (Pin 2). A logic
LOW on RE will enable the receiver, a logic
HIGH on RE will disable the receiver.
The receiver of the SP3483 will operate
up to 250kbps. The receiver is equipped
with the fail-safe feature. Fail-safe guar-
antees that the receiver output will be in a
HIGH state when the input is left uncon-
nected (open circuit).
Shutdown Mode
The SP3483 is equipped with a Shutdown
mode. To enable the shutdown state, both
driver and receiver must be disabled simul-
taneously. A logic LOW on DE (pin 3) and
a Logic HIGH on RE (pin 2) will put the
SP3483 into Shutdown mode. In Shutdown,
supply current will drop to typically 1µA,
10µA maximum.
DESCRIPTION
8
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 510-668-7017 • www.exar.com SP3483_100_010912
9
Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 510-668-7017 • www.exar.com SP3483_100_010912
ORDERING INFORMATION
Model Temperature Range Package Types
SP3483CN-L ....................................................................... 0°C to +70°C ................................................................................................8-pin NSOIC
SP3483CN-L/TR ................................................................. 0°C to +70°C ................................................................................................8-pin NSOIC
SP3483EN-L...................................................................... -40°C to +85°C...............................................................................................8-pin NSOIC
SP3483EN-L/TR................................................................. -40°C to +85°C.............................................................................................8-pin NSOIC
REVISION HISTORY
DATE REVISION DESCRIPTION
06/23/04 -- Legacy Sipex Datasheet
01/09/12 1.0.0 Convert to Exar Format. Update ordering information as a result of discontinued
Lead type package options. Add new Figure 8 - Driver Short Circuit Current Limit
Test Circuit. Correct type error for no load supply current.
Notice
EXAR Corporation reserves the right to make changes to any products contained in this publication in order to improve design, performance or reliabil-
ity. EXAR Corporation assumes no representation that the circuits are free of patent infringement. Charts and schedules contained herein are only for
illustration purposes and may vary depending upon a user's specic application. While the information in this publication has been carefully checked;
no responsibility, however, is assumed for inaccuracies.
EXAR Corporation does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can
reasonably be expected to cause failure of the life support system or to signicantly affect its safety or effectiveness. Products are not authorized for
use in such applications unless EXAR Corporation receives, in writing, assurances to its satisfaction that: (a) the risk of injury or damage has been
minimized ; (b) the user assumes all such risks; (c) potential liability of EXAR Corporation is adequately protected under the circumstances.
Copyright 2012 EXAR Corporation
Datasheet January 2012
Send your serial transceiver technical inquiry with technical details to: serialtechsupport@exar.com
Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited.
Note: /TR = Tape and Reel