Analog Devices, Inc. a global leader in high-performance signal processing technology, and Bourns, Inc., a leading manufacturer and supplier of electronic components, have introduced the industry's first certified RS-485 evaluation board for protecting against EMC (electro-magnetic compatibility) events in industrial and instrumentation equipment. Available from Anglia, the EVAL-CN0313-SDPZ board incorporates ADI's ADM3485E, 3.3-V RS-485 transceiver. The board also incorporates 4 circuit protection devices from Bourns®, Gas Discharge Tube (2038-15-SM-RPLF), TVS Diode array (CDSOT23-SM712), TBU® High-speed protector (TBU-CA065-200-WH) and a Thyristor overvoltage protector (TISP4240M3BJR-S). The board meets IEC61000-4-2/4/5 ESD (electro-static discharge), EFT (electronically-fast transients), and power-surge specifications.

Download Analog Devices EVAL-CN0313-SDPZ circuit note.
Download Bourns 2038-15-SM-RPLF Gas Discharge Tube datasheet.
Download Bourns CDSOT23-SM712 TVS Diode array datasheet.
Download Bourns TBU-CA065-200-WH TBU® High-speed protector datasheet.
Download Bourns TISP4240M3BJR-S TISP Thyristor overvoltage protector datasheet.

The board is offered as part of ADI's Circuits from the Lab™ reference circuits library and includes circuit notes, test data and results to help engineers reduce design risk in applications such as motor controls, grid tied inverters, and programmable-logic controllers. The challenge of matching the EMC characteristics of external protection devices and the components they are designed to protect is among the biggest contributors to schedule and cost overruns for manufacturers of industrial and instrumentation equipment.
As the first externally certified EMC-compliant design tool for RS-485 circuits, the EVAL-CN0313-SDPZ board provides design and integration files, device drivers, and evaluation hardware. Download the design and integration files here.

The EVAL-CN0313-SDPZ also includes an EI3 Hirose connector that allows the board to be used with ADI's ezLINX™ iCoupler® Isolated Interface Development Environment, which provides developers with a cost-effective, plug-and-play method to evaluate the digitally-isolated RS-485 physical communication layer. Click here for more information on the ezLINX™ iCoupler® Isolated Interface Development Environment.

Evaluation Board Key Features

Certified to protect ADI's ADM3485E, 3.3-V RS-485 transceiver for:

• 6-kV, 4-kV and 1-kV surge (IEC61000-4-5)
• 2-kV EFT (IEC61000-4-4)
• 15-kV air-discharge and 8-kV contact ESD (IEC61000-4-2)

The EVAL-CN0313-SDPZ evaluation board includes 3 separate circuits.

Figure 1. EMC Compliant RS-485 Transceiver Protection Circuits included on the EVAL-CN0313-SDPZ evaluation board

In the first protection circuit, shown in Figure 1 as TVS, it uses one component, the Bourns CDSOT23-SM712. This is the transient voltage suppressor (TVS) array shown on the EVAL-CN0313-SDPZ. It consists of two bidirectional TVS diodes optimized to protect RS-485 systems with minimal overstress while allowing the full range of the RS-485 signal and common-mode excursions.

The TVS has high impedance to ground in normal operating conditions. When an overvoltage occurs, the TVS enters into avalanche breakdown mode and clamps the pin voltage to a safe predetermined level. It then diverts the transient current away from the ADM3485E to ground.

This protection scheme offers up to 8 kV contact and15 kV air discharge ESD, 2 kV EFT, and 1 kV surge protection.

As described in the CDSOT23-SM712 data sheet, the part is designed specifically for RS-485 devices. The next two protection schemes add to the CDSOT23-SM712 to provide higher levels of circuit protection against surge.

In the second scheme, shown in Figure 1 as TVS/TBU/TISP, the CDSOT23-SM712 TVS provides secondary protection, and Bourns TISP4240M3BJR-S provides the primary protection. The TISP4240M3BJR-S is a totally integrated surge protector (TISP). The TISP is a solid-state thyristor. When its predetermined voltage is exceeded, the TISP provides a low impedance path to ground, diverting a majority of the transient energy away from the ADM3485E.

Bourns TBU-CA065-200-WH transient blocking unit (TBU) is a nonlinear overcurrent protection device between the primary and secondary protection devices that ensures coordination occurs. The TBU is an overcurrent blocking device that becomes an open circuit at a predefined current. In blocking mode, TBU has very high impedance to block transient energy. This protection scheme offers up to 8 kV contact and15 kV air discharge ESD, 2 kV EFT, and 4 kV surge protection.

The third protection scheme, shown in Figure 1 as TVS/TBU/ GDT, operates in a similar fashion to Protection Scheme 2. In this scheme, a gas discharge tube (GDT) is used instead of the TISP. The GDT protects to higher overvoltages and overcurrents than the TISP described in the previous protection scheme. A GDT is a gas discharge plasma device that provides a low impedance path to ground to protect against over voltage transients. The selected GDT is the Bourns 2038-15-SM-RPLF. This third protection scheme offers up to 8 kV contact and 15 kV air discharge ESD, 2 kV EFT, and 6 kV surge protection.

Click on video below for a brief overview of the EVAL-CN0313-SDPZ certified EMC compliant RS-485 interface evaluation board.

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Click here for more information or buy from Anglia Live.

Anglia are offering customers a FREE EVAL-CN0313-SDPZ evaluation board from Analog Devices and FREE samples of the Bourns circuit protection devices utilised on the evaluation board. Please fill in the form below to register your interest now.

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About Bourns

Bourns, Inc. is a leading manufacturer and supplier of automotive sensors, circuit protection solutions, magnetic products, microelectronic modules, trimming and precision potentiometers, panel controls and encoders and resistive products. Headquartered in Riverside, CA, Bourns serves a broad range of markets, including telecommunications, computer, industrial, instrumentation, automotive, consumer, non-critical life support medical, audio and various other market segments. Bourns products are manufactured according to ISO-9000 standards under Six Sigma quality programs. Bourns automotive products are manufactured in accordance with the TS16949 standard.

About Analog Devices

Innovation, performance, and excellence are the cultural pillars on which Analog Devices has built one of the longest standing, highest growth companies within the technology sector. Acknowledged industry-wide as the world leader in data conversion and signal conditioning technology, Analog Devices serves over 60,000 customers, representing virtually all types of electronic equipment. Analog Devices is headquartered in Norwood, Massachusetts, with design and manufacturing facilities throughout the world. Analog Devices is included in the S&P 500 Index.

For more information, or details on the full range of Analog Devices and Bourns products available from Anglia, please email info@anglia.com