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SP4082E
5V RS-485/RS-422 Transceivers 1/8th Unit Load, Slew-Rate Limited, 15kV ESD-Protected
FEATURES
* 5.0V single supply operation * Receiver failsafe on open or shorted lines * /8th Unit Load, 256 transceivers on bus * Robust ESD protection for RS-485 pins 5kV Human Body Model * Controlled driver slew rates 5kbps, Low EMI *Driver short circuit current limit and thermal shutdown for overload protection *Industry standard package footprints
RO 1 RE 2 DE 3 DI 4
8 PIN NSOIC SP4082E Half Duplex
8 Vcc 7B 6A 5 GND
APPLICATIONS
* Motor Control * Building Automation * Security Systems * Remote Meter Reading * Long or un-terminated transmission lines
The SP4082E is designed for reliable, bidirectional communication on multipoint bus transmission lines. The device contains one differential driver and one differential receiver. It is a half-duplex device. The device complys with TIA/EIA-485 and TIA/EIA-422 standards. Lead-free and RoHS compliant packages are available. This device is ruggedized for use in harsh operating conditions over the entire common-mode voltage range from -7V to +2V. Receivers are specially designed to fail-safe to a logic high output state if the inputs are un-driven or shorted. All RS-485 bus-pins are protected against severe ESD events up to 15kV (Human Body Model). Drivers are protected from excess current flow caused by bus contention or output short-circuits by both an internal current limit and a thermal-overload shutdown. Devices are rated for industrial (-40 to +85C) operating temperatures. Receivers have exceptionally high input impedance, which places only /8th the standard load on a shared bus. Up to 256 transceivers may coexist while preserving full signal margin. The device operates from a single 5.0V power supply and draws negligible quiescent power. The device has an independent enable and disable for the driver and receiver and will enter a low power shutdown mode if both driver and receiver are disabled. All outputs maintain high impedance during shutdown or when powered-off.
DESCRIPTION
Exar Corporation 48720 Kato Road, Fremont CA, 94538 * (50)6687000 * Fax (50)668-707 * www.exar.com
SP4082E_00_22007
PIN ASSIGNMENTS Pin Number Pin Name 2 RO RER Pin Function Receiver Output. When RE is low and if (A - B) -40mV, RO is high. If (A - B) - 200mV, RO is low. Receiver Output Enable. When RE is low, RO is enabled. When RE is high, RO is high impedance. Drive RE high and DE low to enter shutdown mode. Driver Output Enable. When DE is high, outputs are enabled. When DE is low, outputs are high impedance. Drive DE low and RE high to enter shutdown mode. Driver Input. With DE high, a low level on DI forces noninverting output low and inverting output high. A high level on DI forces non-inverting output high and inverting output low. Ground Non-inverting Receiver Input and Non-inverting Driver Output Inverting Receiver Input and Inverting Driver Output Positive Supply VCC. Bypass to GND with a 0.uF capacitor.
EREE
3
DE
4 5 6 7 8
DI GND A B Vcc
DEVICE ARCHITECTURE AND BLOCK DIAGRAM
RO
2 RE DE 3 4 DI
R
8 VCC 7B 6 A 5 GND 8-Pin Half Duplex
D
Exar Corporation 48720 Kato Road, Fremont CA, 94538 * (50)6687000 * Fax (50)668-707 * www.exar.com
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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.
Supply Voltage (VCC)...............................................+ 7.0V Input voltage at control input pins (RE, DE) ..... -0.3V to Vcc+0.3V Driver input voltage (DI) .....................-0.3V to Vcc+0.3V Driver output voltage (A, B, Y, and Z) ...................+/-3V Receiver output voltage (RO) ........-0.3V to (Vcc + 0.3V) Receiver input voltage (A, B) ................................+/-3V Package Power Dissipation: Maximum Junction Temperature 50C 8-Pin SO Oja = 28.4C/W Storage Temperature.............................-65C to +50C Lead Temperature (soldering, 0s)..................... +300C
Vcc=5V 5%, Tmin to Tmax, unless otherwise noted, Typical values are Vcc=5V and Ta=25C
Recommended Operating Conditions Supply Voltage, Vcc Input Voltage on A and B pins High-level input voltage (DI, DE or RE), Vih Low-level input voltage (DI, DE or RE), Vih Output Current Driver Receiver Operating Free Air Temperature, Ta Industrial Grade (E) Min. 4.5 -7 2 0 -60 -8 -40 Nom. 5 Max. 5.5 2 Vcc 0.8 60 8 85
RECOMMENDED OPERATING CONDITIONS
Unit V V V V
mA
C
Note: The least positive (most negative) limit is designated as the maxium value.
Exar Corporation 48720 Kato Road, Fremont CA, 94538 * (50)6687000 * Fax (50)668-707 * www.exar.com
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ELECTRICAL CHARACTERISTICS
PARAMETER Digital Input Signals: DI, DE, RE High, Vih Low, Vil Ta = 25C, after first transition Ta = 25C 00 2.0 0.8 TEST CONDITIONS MIN TYP MAx UNIT
Logic input thresholds Logic Input Current Input Hysteresis Driver Differential Driver Output (Vod) Differential Driver Output, Test Differential Driver Output, Test 2 Change in Magnitude of Differential Output Voltage (Vod) (Note ) Driver Common Mode Output Voltage (Voc) Change in Common Mode Output Voltage (Voc) Driver Short Circuit Current Limit
V A mV
No Load Rl=100 (RS-422) Rl=54 (RS-485) Vcm = -7 to +2V Rl=54 or 100 Rl=54 or 100 Rl=54 or 100 -7V Vout +12V DE=0, Vout=2V Vout= -7V -00 2 .5 .5 2.7
Vcc Vcc Vcc Vcc 0.2 3 0.2 250 25
V
V
V V V mA
Output Leakage Current
RE=0, Vcc=0 or 5.5V
A
Receiver Receiver Input Resistance Input Current (A, B pins) -7V Vcm 12V DE=0, RE=0, Vcc=0 or 5.5V Vin= 2V Vin= -7V -00 -200 -25 25 Iout = -8mA, Vid = -40mV Iout = 8mA, Vid = -200mV Vcc =5.5V, 0 Vout Vcc 0V Vro Vcc Vcc-.5 0.4 95 A mA -40 96 25 A mV mV V K
Receiver Differential Threshold (VA-VB) Receiver Input Hysteresis Receiver Output Voltage Voh Vol
-7V Vcm 12V
High-Z Receiver Output Current Receiver Output Short Circuit Current Supply and Protection Supply Current IQ, Active Mode Shutdown Mode, Note 2
No load, DI=0 or Vcc DE=0, RE=Vcc, DI=Vcc Junction temperature
400
900
A A
o
Thermal Shutdown Temperature Thermal Shutdown Hysteresis
65 5
C
Notes: . Change in Magnitude of Differential Output Voltage and Change in Magnitude of Common Mode Output Voltage are the changes in output voltage when DI input changes state. 2. The transceivers are put into shutdown by bringing RE high and DE low. If the inputs are in this state for less than 50ns the device does not enter shutdown. If the enable inputs are held in this state for at least 600ns the device is assured to be in shutdown. In this low power mode most circuitry is disabled and supply current is typically nA. 3.Characterized, not 00% tested.
Exar Corporation 48720 Kato Road, Fremont CA, 94538 * (50)6687000 * Fax (50)668-707 * www.exar.com
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TIMING CHARACTERISTICS
Unless otherwise noted Vcc= +5.00.5V, ambient temperature TA from -40 to +85C
DRIVER CHARACTERISTICS: Data Signaling Rate ( / tUI) Driver Propagation Delay (tPHL, tPLH) Driver Output Rise/Fall Time (tR, tF) Driver Differential Skew (tPLH - tPHL) Driver Enable to Output High (tDZH) Driver Enable to Output Low (tDZL) Driver Disable from Output High (tDHZ) Driver Disable from Output Low (tDLZ) Shutdown to Driver Output Valid (tDZV) RECEIVER CHARACTERISTICS: Receiver Propagation Delay Prop. Delay Skew (tPLH - tPHL) Receiver Output Rise / Fall Time (tR, tF) Receiver Enable to Output High (tZH) Receiver Enable to Output Low (tZL) Receiver Disable from Output High (tHZ) Receiver Disable from Output Low (tLZ) Shutdown to Receiver Output Valid (tROV) Time to Shutdown (Note 2,3) 50 CL = 5pF Conditions CL = 5pF, VID = 2V Conditions Duty Cycle 40 to 60% RL = 54, CL = 50pF, Min. Typ. Max. Unit 5 3500 667 200 2500 500 3500 3500 00 00 6000 Kbps ns ns ns ns ns ns ns ns
Min. Typ. Max Unit 250 50 50 00 00 00 00 3500 600 ns ns ns ns ns ns ns ns ns
Exar Corporation 48720 Kato Road, Fremont CA, 94538 * (50)6687000 * Fax (50)668-707 * www.exar.com
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DESCRIPTION
Driver DC Test Circuit
Receiver DC Test Circuit
Driver Propagation Delay Time Test Circuit and Timing Diagram
Exar Corporation 48720 Kato Road, Fremont CA, 94538 * (50)6687000 * Fax (50)668-707 * www.exar.com
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DESCRIPTION Driver Differential Output Test Circuit
DE= 3V A/Y DI= 0 or VCC D B/Z 375 VOD 60 VCM 375
Driver Enable and Disable Times Test Circuit and Timing Diagram
0 or VCC DI
Y D Z
S OUT CL=50pF RL= 5001/2
GENERATOR
501/2
VCC VCC /2 DE tZL, tZL(SHDN) VOM = (VOL + VCC)/2 OUT 0.25V tLZ 0 0
Exar Corporation 48720 Kato Road, Fremont CA, 94538 * (50)6687000 * Fax (50)668-707 * www.exar.com
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VCC OUT VOL VOM = (VOL+ VCC)/2
tLZ
DESCRIPTION 0.25V
Receiver Propagation Delay Test Circuit and Timing Diagram
A VID B R RE
OUT CL 5pF
A B tPHL .5V OUT tPLH
+V -V VOH VOL
Exar Corporation 48720 Kato Road, Fremont CA, 94538 * (50)6687000 * Fax (50)668-707 * www.exar.com
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DESCRIPTION Receiver Enable and Disable Times Test Circuit
.5V -.5V S3 B A RE
GENERATOR
K1/2
S S2
VCC
CL=5pF
501/2
Receiver Enable and DisableTiming Diagram
S is open, S2 is closed, S3=.5V 3V RE .5V tZH, tZH(SHDN) VOH OUT VOH/2
S is closed, S2 is open, S3= -.5V 3V RE .5V tZL, tZL(SHDN) 0V VCC 0V OUT VOL = VCC/2 VOL
S is open, S2 is closed, S3=.5V RE 0.25V OUT .5V
S is closed, S2 is open, S3= -.5V 3V RE .5V tLZ VOH 0V OUT 0.25V 0V VCC VOL 3V
Exar Corporation 48720 Kato Road, Fremont CA, 94538 * (50)6687000 * Fax (50)668-707 * www.exar.com
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FUNCTION TABLES
Transmitting RE X X 0 Inputs DE 0 0 Outputs DI 0 X X A 0 High-Z Shutdown B 0 RE 0 0 0 DE X X X 0 Receiving Inputs VA - VB -40mV -200mV Open/shorted X X Output RO 0 High-Z Shutdown
Note: Receiver inputs -200mV < VA - VB < -40mV, should be considered indeterminate
Exar Corporation 48720 Kato Road, Fremont CA, 94538 * (50)6687000 * Fax (50)668-707 * www.exar.com
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DETAILED DESCRIPTION The SP4082E is a 5V half-duplex RS-485 transceiver. The SP4082E contains one driver and one receiver. These devices feature fail-safe circuitry that will guarantee a logic-high receiver output when the receiver inputs are open or shorted. The SP4082E features reduced slew-rate drivers that minimize EMI and reduce reflections caused by improperly terminated cables, allowing error-free data transmission up to 5kbps. It operates from a single 5.0V supply. Drivers are output short-circuit current limited. Thermal-shutdown circuitry protects drivers against excessive power dissipation. When activated, the thermal-shutdown circuitry places the driver outputs into a high-impedance state. Receiver FAILSAFE Ordinary RS-485 differential receivers will be in an indeterminate state whenever A - B is less than 200mV. This situation can occur whenever the data bus is not being actively driven. The Failsafe feature guarantees a logic-high receiver output if the receiver's differential inputs are shorted or open-circuit. The receiver thresholds of the SP4082E are very precise and offset by at least a 40mV noise margin from ground. This results in a logic-high receiver output at zero volts input differential while maintaining compliance with the EIA/TIA485 standard of 200mV. 15KV ESD PROTECTION ESD-protection structures are incorporated on all pins to protect against electrostatic discharges encountered during handling and assembly. The driver output and receiver inputs have extra protection against static electricity. Sipex uses state of the art structures to protect these pins against ESD of 5kV without damage. The ESD structures withstand high ESD in all states: normal operation, shutdown, and powered down. After an ESD event, the SP4082E keeps working without latch-up or damage. ESD protection can be tested in various ways. The transmitter outputs and receiver inputs of
the SP4082E is characterized for protection to the following limits: 5kV using the Human Body Model ESD TEST CONDITIONS ESD performance depends on a variety of conditions. Contact Sipex for a reliability report that documents test setup, methodology and results. MACHINE MODEL The machine model for ESD tests all pins using a 200pF storage capacitor and zero discharge resistance. The objective is to emulate the stress caused when I/O pins are contacted by handling equipment during test and assembly. 256 TRANSCEIVERS ON THE BUS The standard RS-485 receiver input impedance is 12k (1 unit load). A standard driver can drive up to 32 unit loads. The SP4032E has only a /8th unit load receiver input impedance (96k), thereby allowing eight times as many, up to 256, transceivers to be connected in parallel on a communication line. Any combination of these devices and other RS-485 transceivers up to a total of 32 unit loads may be connected to the line. LOW POWER SHUTDOWN MODE Low-power shutdown mode is initiated by bringing both RE high and DE low simultaneously. While in shutdown devices typically draw only 50nA of supply current. DE and RE may be tied together and driven by a single control signal. Devices are guaranteed not to enter shutdown if RE is high and DE is low for less than 50ns. If the inputs are in this state for at least 600ns, the parts are shutdown. Enable times tZH and tZL apply when the part is not in low-power shutdown state. Enable times tZH(SHDN) and tZL(SHDN) apply when the parts are shut down. The drivers and receivers take longer to become enabled from low power shutdown mode tZL(SHDN) and tZL(SHDN) than from driver/receiver-disable mode (tZH, tZL). DRIVER OUTPUT PROTECTION Two mechanisms prevent excessive output current and power dissipation caused by faults or by bus contention. First, a driver current limit on the output stage provides immediate protecSP4082E_00_22007
DESCRIPTION
Exar Corporation 48720 Kato Road, Fremont CA, 94538 * (50)6687000 * Fax (50)668-707 * www.exar.com
tion against short circuits over the whole common-mode voltage range. Second, a thermalshutdown circuit forces the driver outputs into a high-impedance state if junction temperature becomes excessive. LINE LENGTH, EMI, AND REFLECTIONS It features controlled slew-rate drivers that minimize EMI and reduce reflections caused by improperly terminated cables. Driver rise and fall times are limited to no faster than 667ns, allowing error-free data transmission up to 5kbps. The RS-485/RS-422 standard covers line lengths up to 4,000ft. Maximum achievable line length is a function of signal attenuation and noise. Use of slew-controlled drivers may help to reduce crosstalk interference and permit communication over longer transmission lines. Termination prevents reflections by eliminating the impedance mismatches on a transmission line. Line termination is typically used if rise and fall times are shorter than the round-trip signal propagation time. Slew-limited drivers may reduce or eliminate the need for cable termination in many applications.
DESCRIPTION
TYPICAL APPLICATIONS: Half-Duplex Network H alf -D uplex N etw ork
Exar Corporation 48720 Kato Road, Fremont CA, 94538 * (50)6687000 * Fax (50)668-707 * www.exar.com
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Exar Corporation 48720 Kato Road, Fremont CA, 94538 * (50)6687000 * Fax (50)668-707 * www.exar.com
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ORDERING INFORMATION Part number LEAD FREE Tape & Reel SP4082EEN -L /TR Temperature range From -40 to +850C Package Type 8 pin nSOIC
All packages are available as lead free (RoHS compliant). To order add "-L" suffix to part number. For Tape and Reel add "/TR". Reel quantity is 2,500 for NSOIC. Example: SP4082EEN-L/TR = lead free and Tape and Reel. SP4082EEN/TR = standard with Tape and Reel.
Notice EXAR Corporation reserves the right to make changes to any products contained in this publication in order to improve design, performance or reliability. 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 specific 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 significantly affect its safety or effectiveness. Products are not authorized for use in such applications unless EXAR Corporation receives, in writting, 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 2007 EXAR Corporation Datasheet December 2007 Send your Interface technical inquiry with technical details to: customersupport@exar.com Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited. Exar Corporation 48720 Kato Road, Fremont CA, 94538 * (50)6687000 * Fax (50)668-707 * www.exar.com SP4082E_00_22007
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