Overview
| Information | Programmable RS-232/RS-485 Transceiver |
|---|---|
| Supported Protocols | RS232, V.28, RS485, RS422, V.24 |
| Supply Voltage (Nom) (V) | 5 |
| 232 Tx / Rx | 3 / 5 |
| 485 Tx / Rx | 2 / 2 |
| RS-232 Max Data Rate (Mbps) | 0.12 |
| RS-485/RS-422 Max Data Rate (Mbps) | 10 |
| HBM ESD (kV) | 2 |
| IEC 61000-4-2 Contact (±kV) | - |
| 120Ω Termination | |
| VL Pin | |
| 232 Full Handshake | |
| Slew Limit Pin | |
| Fault Tolerance (V) | |
| RS-485 Duplex | Full |
| Max ICC (mA) | 50 |
| Temperature Range (°C) | 0 to 70, -40 to 85 |
| Package | SOIC-28 |
The SP334 is a programmable RS-232 and/or RS-485 transceiver IC. The SP334 contains three drivers and five receivers when selected in RS-232 mode; and two drivers and two receivers when selected in RS-485 mode.
The RS-232 transceivers can typically operate at 230kbps while adhering to the RS-232 specifications. The RS-485 transceivers can operate up to 10Mbps while adhering to the RS-485 specifications. The RS-485 drivers can be disabled (High-Z output) by the TXEN enable pin. The RS-232 and RS-485 receiver outputs can be disabled by the RXEN enable pin.
- +5V Only Operation
- Software Programmable RS-232 or RS-485 Selection
- Three RS-232 Drivers and Five Receivers in RS-232 Mode
- Two RS-485 Full-Duplex Transceivers in RS-485 Mode
- Full Differential Driver Tri-State (Hi-Z) Control
- Receiver Output Tri-State Control
- 2Tx/5Rx
Documentation & Design Tools
All Types
Data Sheets
Application Notes
Schematics & Design Files
Product Briefs & Brochures
User Guides & Manuals
| Type | Title | Version | Date | File Size |
|---|---|---|---|---|
| Data Sheets | SP334 Programmable RS-232/RS-485 Transceiver | 1.0.1 | April 2018 | 521 KB |
| Application Notes | Advantages of Designing with Multi-Protocol Transceivers Application Note | R00 | September 2023 | 2.5 MB |
| Application Notes | DAN-190, MaxLinear UARTs in RS-485 Applications | R01 | July 2023 | 2.4 MB |
| Application Notes | RS-232 and RS-485 PCB Layout Application Note | R00 | December 2022 | 2.8 MB |
| Application Notes | ANI-16, Design Guide for Multi-Protocol Serial Ports | A | November 2005 | 462.9 KB |
| User Guides & Manuals | XR21B1420 Evaluation Board User’s Manual | 1B | January 2020 | 1.2 MB |
| Product Brochures | Interface Brochure | R02 | November 2024 | 3.6 MB |
| Product FAQs | SP334 FAQ | 1.0.0 | August 2007 | 181.5 KB |
| Schematics & Design Files | XR21B1420/1421 Evaluation Board Design Files | REV 10 | June 2016 | 386.5 KB |
Quality & RoHS
| Part Number | RoHS | Exempt | RoHS | Halogen Free | REACH | TSCA | MSL Rating / Peak Reflow | Package |
|---|---|---|---|---|---|---|---|
| SP334CT-L | N | Y | Y | Y | Y | L3 / 260ᵒC | WSOIC28 |
| SP334CT-L/TR | N | Y | Y | Y | Y | L3 / 260ᵒC | WSOIC28 |
| SP334ET-L | N | Y | Y | Y | Y | L3 / 260ᵒC | WSOIC28 |
| SP334ET-L/TR | N | Y | Y | Y | Y | L3 / 260ᵒC | WSOIC28 |
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 |
|---|---|---|---|---|---|---|---|---|
| SP334CA | SSOP28 | 0 | 70 | OBS | ||||
| SP334CA-L | SSOP28 | 0 | 70 | OBS | ||||
| SP334CA/TR | SSOP28 | 0 | 70 | OBS | ||||
| SP334CT | WSOIC28 | 0 | 70 | OBS | SP334CT-L | |||
| SP334CT-L | WSOIC28 | 0 | 70 | Active | Order | |||
| SP334CT-L/TR | WSOIC28 | 0 | 70 | Active | Order | |||
| SP334CT/TR | WSOIC28 | 0 | 70 | OBS | SP334CT-L/TR | |||
| SP334ET | WSOIC28 | -40 | 85 | OBS | SP334ET-L | |||
| SP334ET-L | WSOIC28 | -40 | 85 | Active | Order | |||
| SP334ET-L/TR | WSOIC28 | -40 | 85 | Active | Order | |||
| SP334ET/TR | WSOIC28 | -40 | 85 | OBS | SP334ET-L/TR | |||
| XR21B1420IL28-0A-EVB | Board | Active |
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.
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 |
|---|---|---|---|
| SSOP28 |
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| WSOIC28 |
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Notifications
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).
Yes, the SP331, SP332 and SP334 exceed ±2kV ESD HBM on all pins. Some interface products have enhanced versions that exceed ±15kV, which applies to the bus data lines. The parametric search contains ESD information and it is a selection field https://www.exar.com/products/interface/serial-transceivers/multiprotocol/dual-protocol .
On the bench we measured an SP334 device. Pin 3 is not tri-state in RS232 mode. It appears to have low impedance pullup to the Vcc. If pin 2 is pulled high in RS232 mode, the pullup looks like 1k Ohm to VCC.
Pin 3 and pin 15 could be tied together but since pin 3 is a low impedance to Vcc the driver may have a hard time driving this pin. Pull pin 2 high and if your driver can drive 1kOhm you may be able to achieve what you want. As long as your driver is strong enough to drive the pin 3,15 combination then pin 19 will respond.
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.
Visit the product page for the part you are interested in. The part's status is listed in the Parts & Purchasing section. You can also view Product Lifecycle and Obsolescence Information including PDNs (Product Discontinuation Notifications).
To visit a product page, type the part into the search window on the top of the MaxLinear website.
In this example, we searched for XRA1201. Visit the product page by clicking the part number or visit the orderable parts list by clicking "Orderable Parts".
The Parts & Purchasing section of the product page shows the Status of all orderable part numbers for that product. Click Show obsolete parts, to see all EOL or OBS products.
The SP334 does not allow for both RS-232 and RS-485 protocols at the same time. Yes, it is correct in that if a termination resistor is used for RS-485 mode it must be fully removed from circuit during RS-232 mode. This can be done by using either relay or low resistance FET to connect / disconnect the termination resistor. The SP334 RS-485 protocol can be used for Half-duplex operation by connecting RXIN to TXout. If you wish to switch from Half-duplex to Full-duplex you will need a switch / relay for this operation or manual jumpers.
Videos
How to Design a Multiprotocol System using Only 1 Connector
Industrial networks support multiple serial interfaces such as RS-485 and RS-232. Using a multiprotocol transceiver enables industrial equipment to support both protocols using only one connector. Enabling both smaller and lower cost equipment designs. This video describes how to design multiprotocol systems using only one connector.
