✔ Protection Diode Rs485

A common tvs diode for rs 485 applications is the sm712. White paperovervoltage protection for rs 485 bus nodes page 4 of 6 receivers stay operational during thermal shutdown and fault protection is active regardless of whether the driver is enabled disabled or the ic is powered down.

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Sn65hvd82 How To Handle Esd Protection For Isolated Rs 485

Usb To Rs232 Rs485 Ttl Industrial Isolated Converter

Rs 485 has long been a workhorse communication standard for industrial and communications electronics.

Protection diode rs485. Also its clamping voltage is close to the limit of the ti thvd1500 as seen in figure 6. A general protection scheme for an rs 485 network includes a tvs diode array such as the bourns model cdsot23 sm712 device on each node. 5 system design theory this ti design features the cdsot23 sm712 tvs diode from bourns inc series pulse proof resistors a pad site for an 8 pin soic rs 485 transceiver with the sn65hvd82 installed and.

This provides the overvoltage protection for the rs 485 transceiver. Maybe putting some movs on the bus would be a better idea. The sn65hvd82 supports 12 kv of iec esd protection 16 kv hbm protection and 4kv iec eft protection on die.

Protecting rs 485interfaces against lethal electrical transients thomas kugelstadt. Begingroup rs485 has a common mode range that extends from 12 to 7v with respect to ground so those diodes are overly conservative and while they will protect the chip they will also stop the receiver working in the presence of common mode. Icp industrial interface abstract industrial networks must operate reliably in harsh environments.

Protection for rs 485 ports single stage protection usually consists of a single tvs device on each data line. How effective in general are zeners at this type of overvoltage protection. From high end base stations to surveillance to hvac control to pos terminals to industrial networks.

On an rs 485 transmission line i would think some pretty large voltage spikes could be induced wouldnt the diodes blow up pretty easily with a large spike. Ii tvs diode array sm712 is specifically designed to help protect rs 485. This tvs has asymmetrical reverse stand off voltages to match the common mode operating range of an rs 485 application.

When blown to they fail open or closed circuit. Rs 485 is still widely prevalent today for its advantages in robust high noise immunity electrical communication. A general protection scheme for each node of an rs 485 network includes a tvs diode array such as the cdsot23 sm712 from bourns.

Intra building protection recommendations rs 485 technology series i resettable pptc trf250600 ts250 tsv250 ii tvs diode sm712 resettable pptc can increase up time by helping to protect equipment from short circuit and power cross event. This single stage bidirectional device provides asymmetrical overvoltage protection for the rs 485 transceiver across the entire 7 v to 12 v common mode voltage range.