SP4082E

5V RS-485/RS-422 Half-Duplex Transceiver
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Overview

Information 5V RS-485/RS-422 Half-Duplex Transceiver
Supported Protocols RS-422, RS-485
Supply Voltage (Nom) (V) 5
No. of Tx 1
No. of Rx 1
Duplex Half
Data Rate (MAX) (Mbps) 0.115
HBM ESD (kV) 15
IEC 61000-4-2 Contact (±kV) -
Rx Fail-Safe Standard
Multi-Drop Nodes 256
Transient Tolerance (V)
Fault Tolerance (V)
VL Pin
Temperature Range (°C) -40 to 85
Package NSOIC-8
ICC (Max) (mA) 0.9
Shutdown
Typ Shutdown Current (µA) 400
Hot Swap
PROFIBUS (5V) or High Output (3V)
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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 de- vice. The device complies 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 volt- age 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 +85oC) 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.

  • 5.0V Single Supply Operation
  • Controlled Driver Slew Rates 115kbps, Low EMI
  • Receiver Failsafe on Open or Shorted Lines
  • 1/8th Unil Load, 256 Transceivers on Bus
  • Robust ESD Protection for RS-485 Pins +/-15KV Human Body Model
  • Driver Short Circuit Current Limit and Thermal Shutdown for Overload Protection
  • Industry Standard Package Footprints

  • Motor Control
  • Building Automation
  • Security Systems
  • Remote Meter Reading

Documentation & Design Tools

All Types Data Sheets Application Notes Product Briefs & Brochures
Type Title Version Date File Size
Data Sheets SP4082E 5V RS-485/RS-422 Transceivers 1/8th Unit Load, Slew-Rate Limited, ±15kV ESD-Protected 2.0.0 September 2022 448 KB
Application Notes RS-485 Transceivers in Fieldbus Networks R00 October 2024 2.4 MB
Application Notes DAN-190, MaxLinear UARTs in RS-485 Applications R01 July 2023 2.4 MB
Application Notes AN-291, RS-485 Advanced Fail-Safe Feature R01 May 2023 3.7 MB
Application Notes RS-232 and RS-485 PCB Layout Application Note R00 December 2022 2.8 MB
Application Notes AN-292, RS-485 Cable Lengths vs Data Signaling Rate R01 July 2022 2.7 MB
Application Notes ANI-13, RS-485 and RS-422 Physical Topologies D December 2006 183.2 KB
Product Flyers 5V RS-485/RS-422 Half-Duplex Transceiver 1.0.0 June 2008 147.5 KB
Product Brochures Interface Brochure R02 November 2024 3.6 MB
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Quality & RoHS

Part Number RoHS | Exempt RoHS Halogen Free REACH TSCA MSL Rating / Peak Reflow Package
SP4082EEN-L/TR N Y Y Y Y L1 / 260ᵒC NSOIC8

Click on the links above to download the Certificate of Non-Use of Hazardous Substances.

Additional Quality Documentation may be available, please Contact Support.

Parts & Purchasing

Part Number Pkg Code Min Temp Max Temp Status Suggested Replacement Buy Now Order Samples PDN
SP4082EEN-L NSOIC8 -40 85 OBS
SP4082EEN-L/TR NSOIC8 -40 85 Active Order
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Part Status Legend
Active - the part is released for sale, standard product.
EOL (End of Life) - the part is no longer being manufactured, there may or may not be inventory still in stock.
CF (Contact Factory) - the part is still active but customers should check with the factory for availability. Longer lead-times may apply.
PRE (Pre-introduction) - the part has not been introduced or the part number is an early version available for sample only.
OBS (Obsolete) - the part is no longer being manufactured and may not be ordered.
NRND (Not Recommended for New Designs) - the part is not recommended for new designs.

Packaging

Pkg Code Details Quantities Dimensions
NSOIC8
  • JEDEC Reference: MS-012
  • MSL Pb-Free: L1 @ 260ºC
  • MSL SnPb Eutectic: n/a
  • ThetaJA: 128.4ºC/W (std); 96.8ºC/W (fused)
  • Bulk Pack Style: Tube
  • Quantity per Bulk Pack: 98
  • Quantity per Reel: 2500
  • Quantity per Tube: 98
  • Quantity per Tray: n/a
  • Reel Size (Dia. x Width x Pitch): 330 x 12 x 8
  • Tape & Reel Unit Orientation: Quadrant 1
  • Dimensions: mm
  • Length: 4.90
  • Width: 3.90
  • Thickness: 1.75
  • Lead Pitch: 1.27

Notifications

Distribution Date Description File
07/17/2023 In 2023, MaxLinear will be converting all shipping labels for the parts noted from an EXAR format to MaxLinear’s label. During this transition customers may receive either label. This change affects only shipping and packing labels. This change will not affect the part number, part marking, manufacturing process or manufacturing sites. Only work in progress material will be converted. Existing inventory from MaxLinear’s warehouse, channel sales, distributor, and such, will not be converted. Hence, customers may experience receiving mixed shipments with both Exar and MaxLinear labels for some period until existing inventory of old labels is eventually cleared out. Situation is product to product with no predictable way to determine when all old labels will be exhausted. No change to product form, fit, function and reliability. ADDENDUM A: Fixed MBB label logo for DX204001 to MaxLinear logo. ADDENDUM B: Replaced ‘All other affected products outer box label’ with clearer pictures. Corrected Date Issued (from original PCN) issue date +90 days to August 30, 2023.
06/01/2023 In 2023, MaxLinear will be converting all shipping labels for the parts noted from an EXAR format to MaxLinear’s label. During this transition customers may receive either label. This change affects only shipping and packing labels. This change will not affect the part number, part marking, manufacturing process or manufacturing sites. Only work in progress material will be converted. Existing inventory from MaxLinear’s warehouse, channel sales, distributor, and such, will not be converted. Hence, customers may experience receiving mixed shipments with both Exar and MaxLinear labels for some period until existing inventory of old labels is eventually cleared out. Situation is product to product with no predictable way to determine when all old labels will be exhausted. No change to product form, fit, function and reliability.
06/01/2023 In 2023, MaxLinear will be converting all shipping labels for the parts noted from an EXAR format to MaxLinear’s label. During this transition customers may receive either label. This change affects only shipping and packing labels. This change will not affect the part number, part marking, manufacturing process or manufacturing sites. Only work in progress material will be converted. Existing inventory from MaxLinear’s warehouse, channel sales, distributor, and such, will not be converted. Hence, customers may experience receiving mixed shipments with both Exar and MaxLinear labels for some period until existing inventory of old labels is eventually cleared out. Situation is product to product with no predictable way to determine when all old labels will be exhausted. No change to product form, fit, function and reliability. ADDENDUM: Fixed MBB label logo for DX204001 to MaxLinear logo.
08/11/2022 Description and Purpose of Change: MaxLinear has qualified Key Foundry wafer foundry in order to increase production capacity and to facilitate long term support of the product line. The wafer process is 0.18um BCD. The process has been optimized to produce very similar product characteristics as the currently shipping devices from TSMC foundry and will meet existing datasheet specifications. Greatek is qualified for assembly of 8L NSOIC packages and is added as a supplier to the devices included in this notice. There are no changes in device reliability. (See PCN for details)
07/14/2022 Description and Purpose of Change: MaxLinear has qualified Key Foundry wafer foundry in order to increase production capacity and to facilitate long term support of the product line. The wafer process is 0.18um BCD. The process has been optimized to produce very similar product characteristics as the currently shipping devices from TSMC foundry and will meet existing datasheet specifications. Greatek is qualified for assembly of 8L NSOIC packages and is added as a supplier to the devices included in this notice. There are no changes in device reliability. (See PCN for details)
07/11/2017 Product Discontinuation Notification
02/15/2017 Qualification of alternate assembly subcon, ANST.
04/28/2016 Qualification of alternate assembly subcon, JCET.
04/24/2015 Qualification of an alternate foundry site, T6SMC, and alternate assembly sites, Carsem, Ipoh, Malaysia and ASE, Chung-Li, Taiwan using copper or gold wire bonding. Alternate Foundry and Assembly Site.
07/03/2013 Addition of qualified 6 inch wafer processing line in Episil, in addition to the currently qualified 5 inch wafer processing line. Other change (foundry 6 inch wafer qualification).
07/02/2013 Qualification of an alternate qualified assembly supplier, ASE Chung-Li (Taiwan) for the 8L NSOIC package using copper wire bonding. Material change and alternate assembly supplier qualified.
03/08/2012 Wafer Fabrication Facility Wafer foundry request.
12/07/2009 Enhancement of NSOIC 8, NSOIC14 and NSOIC16 packages to Green (halogen-free) via Mold Compound & Die Attach Material. Enhance packages to be Green (halogen-free).
10/03/2008 Wafer Fabrication – Episil 1.2um CMOS To correct auto-doping of N-Well causing Vtp variation and to eliminate device leakage.

FAQs & Support

Search our list of FAQs for answers to common technical questions.
For material content, environmental, quality and reliability questions review the Quality tab or visit our Quality page.
For ordering information and general customer service visit our Contact Us page.

Submit a Technical Support Question As a New Question

For RS-232 it is 50 feet (15 meters), or the cable length equal to a capacitance of 2500 pF, at a maximum transmission rate of 19.2kbps. When we reduce the baud rate, it allows for longer cable length. For Example:

 

Baud Rate (bps)

Maximum RS-232 Cable Length (ft)

19200

50

9600

500

4800

1000

2400

3000
 
For RS-485 / RS-422 the data rate can exceed 10Mbps depending on the cable length. A cable length of 15 meters (50 feet) will do a maximum of 10Mbps. A cable length of 1200 meters (4000 feet) will do a maximum of 90kbps over 24 AWG gauge twisted pair cable (with 10 pF/ft). Refer to Annex A TIA/EIA-422-B. Also refer the RS-485 Cable Lengths vs. Data Signaling Rate Application Note (AN-292).
 
 

As RS-422/RS-485 uses differential signaling, it is more immune to noise and longer cables and/or high data rates can be used, especially in noisy environments. Also, RS-485 allows for multi-point operation, up to 32 unit loads. Transceivers may use a fraction of a unit load, increasing the number of devices on the bus. For example, the XR33152 receiver input impedance is at least 120 kΩ, which equates to 1/10 of a unit load. Therefore, XR33152 allows more than 320 devices (32 x 10) on the bus.

Fail Safe is an attempt to keep the output of the RS-485 receiver to a known state. Transceivers may have standard fail safe or advanced / enhanced receiver fail safe features. Standard fail safe supports open inputs while enhanced fail safe transceivers such as the SP339 and XR34350 support open input, shorted input and undriven terminated lines without external biasing. See Application Note ANI-22 for more detail.

 

Figure 1:  Standard Failsafe Receiver Sensitivity Range
 


 

 
Figure 2: Standard Failsafe with Open Input
 
 
 
Figure 3: Enhanced Failsafe Receiver Sensitivity Range
 
 
 
Figure 4:  Enhanced Failsafe with Open Input
 
 
 
Figure 5:  Enhanced Failsafe with Shorted Input
 
 
 
Figure 6:  Enhanced Failsafe with Un-driven terminated lines
 
 
 

Yes, this is possible using one RS-485 transceiver. The microcontrollers will have to be addressable and have tri-state outputs. The RS-485 device can be controlled by the host via the DE/RE pin. The micros will have to be in either receiving mode or tri-state mode when the RS-485 transceiver is transmitting data. When the host transmits it will have to send an address to the specific micro. If any micro transmits the transceiver will have to be in receiving mode and all other micros will have to be in receive or tri-state. So the host would have to initiate this sequence by addressing the micro first then switch the transceiver to receive.
The half duplex system would have a bus with one transceiver and multiple microcontrollers all tied to the bus. For 5V systems the SP485 family can be used. For 3V systems the SP3070 family can be used. The require speed will determine the part number. The SP3078 part runs up to speeds of 16Mbps.  See the parametric search on https://www.exar.com/products/interface/serial-transceivers/rs485-422 for more options.
Care must be taken to assure the transceiver can drive the multiple micros in RX mode.

ESD tests are “destructive tests.” The part is tested until it suffers damage. Therefore parts cannot be 100% tested in production, instead a sample of parts are characterized during the product qualification. The test procedure consists of “zapping” pins with a given voltage using the appropriate model and then running the part through electrical tests to check for functionality or performance degradation.

ESD is caused by static electricity. In order for an ESD event to occur there must be a buildup of static charge. Very high charge levels are actually quite rare. In a normal factory environment, taking basic ESD precautions (grounding-straps, anti-static smocks, ionizers, humidity control, etc.) static levels can be kept below a few tens of volts. In an uncontrolled environment, like an office, static levels rarely get above 2000 volts. Under some worstcase conditions (wearing synthetic fabrics, rubbing against synthetic upholstered furniture, extremely low humidity)
levels can go as high as 12 to 15 thousand volts. Actually to get to 15000 volts or higher you would need to be in an uncomfortably dry environment (humidity below 10%) otherwise static charge will naturally dissipate through corona discharge. It would definitely be considered a “bad hair day.” Humans can generally feel a static shock only above 3000 volts. A discharge greater than 4000 volts can cause an audible “pop.” But repeated lower level discharges can be imperceptible and still may have a cumulative damaging effect on sensitive ICs. All ICs, even those with robust protection, can be damaged if they are hit hard enough or often enough.

Most ICs in a typical system are at greatest risk of ESD damage in the factory when the PCB is assembled and the system is being built. After the system is put together they are soldered onto the PCB and shielded within a metal or plastic system enclosure. Interface ICs are designed to attach to an external connector that could be exposed to ESD when a cable is plugged in or when a person or object touches the connector. These interface pins are most likely to see ESD exposure and therefore benefit from additional protection.

Actually the letter “E” could have two different meanings, depending on where it is in the part number. Most of our interface devices are available in different temperature grades. Commercial temperature (0 to 70C) has a “C” after the numeric part number. Industrial-extended temperature (-40 to +85C) use the letter E. So for example SP485CN is commercial and SP485EN is industrial. The second letter indicates the package type, in this case N for narrow-SOIC. Another E in the suffix indicates that this device has enhanced ESD protection, typically of ±15000Volts on the interface pins. Devices that do not have the enhanced ESD still contain built-in ESD protection of at least ±2000Volts. For example the SP485ECN is ESD rated up to ±15kV, and the SP485CN is rated for ±2kV HBM.

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Videos

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Tips to Maintain a Successful RS-485 Link

This video provides four tips to help maintain RS-485 serial communication without data loss

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