Rugged 3.3V, 20Mbps, 8 Channel Multiprotocol Transceiver with Programmable DCE/DTE and Termination Resistors
Data Sheet


The SP3508 is a monolithic device that supports eight (8) popular serial interface standards for Wide Area Network (WAN) connectivity. The SP3508 is fabricated using a low power BiCMOS process technology, and incorporates a regulated charge pump allowing +3.3V only operation. Exar's patented charge pump provides a regulated output of +5.5V, which will provide enough voltage for compliant operation in all modes. Eight (8) drivers and eight (8) receivers can be configured via software for any of the above interface modes at any time. The SP3508 requires no additional external components for compliant operation for all of the eight (8) modes of operation other than six capacitors used for the internal charge pump. All necessary termination is integrated within the SP3508 and is switchable when V.35 drivers and V.35 receivers, or when V. receivers are used. The SP3508 provides the controls and transceiver availability for operating as either a DTE or DCE.

Additional features with the SP3508 include internal loopback that can be initiated in any of the operating modes by use of the LOOPBACK pin. While in loopback mode, receiver outputs are internally connected to driver inputs creating an internal signal path bypassing the serial communications controller for diagnostic testing. The SP3508 also includes a latch enable pin with the driver and receiver address decoder. The internal V. or V.35 termination can be switched off using a control pin (TERM_OFF) for monitoring applications. All eight (8) drivers and receivers in the SP3508 include separate enable pins for added convenience. The SP3508 is ideal for WAN serial ports in networking equipment such as routers, access concentrators, network muxes, DSU/CSU's, networking test equipment, and other access devices.


  • Fast 20Mbps Differential Transmission Rates
  • Internal Transceiver Termination Resistors for V.11 & V.35
  • Interface Modes:
    • RS-232 (V.28)
    • EIA-530 (V.10 & V.11)
    • EIA-530A (V.10 & V.11)
    • X.21 (V.11)
    • RS-449/V.36
    • V.35 (V.35 & V.28)
  • Protocols are Software Selectable with 3-Bit Word
  • Eight (8) Drivers and Eight (8) Receivers
  • Termination Network Disable Option
  • Internal Line or Digital Loopback for Diagnostic Testing
  • Certified conformance to NET1/NET2 and TBR-1
  • TBR-2 by TUV Rheinland (TBR2/30451940.001/04)
  • Easy Flow-Through Pinout
  • +3.3V Only Operation
  • Individual Driver and Receiver Enable/Disable Controls
  • Operates in either DTE or DCE Mode


Design Tools

Simulation Models
Package Type Vcc Temp Mode Version File
LQFP 3.3V Commercial V.10 2
LQFP 3.3V Commercial V.28 2
LQFP 3.3V Commercial V.35 2
LQFP 3.3V Industrial V.10 2
LQFP 3.3V Industrial V.28 3
LQFP 3.3V Industrial V.35 3
LQFP 3.3V Commercial 1
LQFP 3.3V Industrial 2


Pkg Code Details Quantities Dimensions PDF
  • JEDEC Reference: MS-026
  • MSL Pb-Free: L3 @ 260ºC
  • MSL SnPb Eutectic: n/a
  • ThetaJA: 45.7ºC/W
  • Bulk Pack Style: Tray
  • Quantity per Bulk Pack: n/a
  • Quantity per Reel: 1000¹
  • Quantity per Tube: n/a
  • Quantity per Tray: 90
  • Reel Size (Dia. x Width x Pitch): 330 x 24 x 20
  • Tape & Reel Unit Orientation: Pin 1 at sprocket hole.
  • Dimensions: mm
  • Length: 14.00
  • Width: 14.00
  • Thickness: 1.60
  • Lead Pitch: 0.50

Parts & Purchasing

Part Number Pkg Code Min Temp Max Temp Status Buy Now Order Samples
SP3508CF LQFP100 0 70 OBS
SP3508CF-L LQFP100 0 70 Active Order
SP3508EF LQFP100 -40 85 OBS
SP3508EF-L LQFP100 -40 85 Active Order
SP3508EB Board -40 85 Active
Show obsolete parts
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.

Quality & Environmental Data

Part Number RoHS | Exempt RoHS Halogen Free REACH MSL Rating / Peak Reflow Package
SP3508CF-L N Y Y Y L3 / 260ᵒC LQFP100
SP3508EF-L N Y Y Y L3 / 260ᵒC LQFP100

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

Additional Quality Documentation may be available, please Contact Support.
Distribution Date Description File
04/04/2017 Qualification of alternate assembly subcon, Greatek, Taiwan.
01/11/2016 Alternate foundry Addition of Silan as an alternate foundry.
10/03/2013 Addition of an alternate qualified assembly site, ASE Chung-Li (Taiwan). Material change and alternate assembly site.
03/08/2012 Wafer Fabrication Facility Wafer foundry request.
08/10/2011 Material change and a new assembly & test supplier (ASE, Kunshan). Business consolidation.
07/30/2010 Process Change. Capacity enhancement.
01/30/2009 Notice of Last-time Buy and Obsolescence Package Discontinuation Notice
01/08/2008 Change of assembly subcontractor for all Sipex part numbers packaged in the 100 lead LQFP packages from Carsem to Unisem’s Batam plant (formerly AIT), and conversion of all Sipex part number in 80 lead MQFP packages built at Carsem to 80 lead LQFP packages built at Unisem’s Batam plant (formerly AIT). Current subcontractor, Carsem, is discontinuing the packages.
02/28/2007 Product Obsolescence Letter and Discontinuation Notification. Discontinued.
06/26/2006 Amendment of PCN transferring certain Power Management and Interface Products from Hillview fabrication and facility to wafer foundary Episil instead of Silan. See attached Product List Power Management and Interface products as listed are being transfer to external wafer foundry, due to cessation of operations of the sipex Hillview Fabrication manufacturing site
05/08/2006 Announcing transfer of certain Power Management and Interface Products from Hillview fabrication and facility to wafer foundary Silan. See attached Product List Power Management and Interface products as listed are being transfer to external wafer foundry, due to cessation of operations of the sipex Hillview Fabrication manufacturing site
02/02/2006 Announcing transfer of certain Power Management and Interface Products from Hillview fabrication and facility to wafer foundary Silan. See attached Product List Power Management and Interface products as listed are being transfer to external wafer foundry, due to cessation of operations of the sipex Hillview Fabrication manufacturing site


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.
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Frequently Asked Questions

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.

The best way to determine this is to go to maxlinear.com and type the part into the search function. At or near the top of the results you should see something that looks like:

In this example, we looked for XRA1201. Click on part number header or on the link at the bottom of the result.  This brings you to the product page. For example:


Click on Parts & Purchasing, highlighted with the blue arrow above. The screen changes to:


Notice the status column and the “Show obsolete parts” link.  A legend tells you the definition of the different statuses. Click on the “Show obsolete parts” link to see EOL or OBS part numbers along with the Active part numbers, the legend still present:


Another method to find out if a part is OBS or EOL is to click on SUPPORT at the top:


And then Product Change Notifications:


Type the part into the search, and click on one of the part numbers from the drop down menu. Then you can look for the Product Discontinuation Notice, which generally is at the top of the list, for example:


If you see this, it tells you that this particular orderable part has been discontinued and when the last order date is, or was. If you click on the file, then you can view the notice we sent about this if you purchased the part in the recent past. It may also advise of a replacement part. When an orderable part first becomes discontinued, Product Discontinuation Notices are sent are sent to those who have purchased the parts in the recent past, if purchased directly, with a dated opportunity to place a last order.

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