Tips on choosing a right isolated transceiver
CONTENTS
There are many isolation solutions for the communication bus, how to choose?
Integrated isolated RS485/CAN transceiver with built-in power supply
Chip level isolated RS485/CAN transceiver without built-in power supply
CAN (Controller Area Network) and RS485 are popular field bus systems for industrial communications. And good isolation protection on the communication bus helps to ensure that products are reliable and stable. So how to do good isolation protection on the communication bus? There are many isolation solutions, how do you choose the right one? Get some tips for the answer in this article!
Why does the communication bus need to be isolated?
The external communication section of most products generally consists of an MCU, a transceiver and an external bus, where most of MCUs have an integrated CAN or UART link layer controller. The level signal from the MCU is usually 5V or 3.3V. For bus connection and remote transmission, it is necessary to add a transceiver between the MCU and the bus to act as a level converter.
Bus communication inevitably involves external communication wiring, and CAN and 485 buses often require hundreds of meters of wiring. The longer the bus wire and the more complex the environment it passes through, the more likely communication problems will occur. The complex and variable electromagnetic fields in the external environment will indirectly increase the potential of the bus, and static electricity, surges and short circuits will directly affect the communication wire. The above situations can lead to damage to the transceiver or to the failure of the mainboard in serious cases. Therefore, it is essential to do isolation protection before connecting to the bus.
There are many isolation solutions for the communication bus, how to choose?
Communication isolation must take into account the effect of isolated devices on the communication signal. Inadequate isolation often results in interrupted or poor communication. For transceivers, isolation can be considered in two aspects, communication isolation and power isolation. The current mainstream communication isolation solution is an optocoupler, capacitive coupler, or magnetic coupler. Power isolation, on the other hand, usually uses a micropower DC/DC isolated power supply, so that there is no electrical connection between the input and output to avoid the influence of the power supply side on the transceiver.
More specifically, isolation can be achieved in two ways: by using discrete components or by using integrated modules. Discrete solutions and integrated modules have their advantages and disadvantages, such as discrete solutions, lower material cost but higher material management cost, longer production time, large PCB layout size, higher failure rate, etc. The integrated module solution, although the material cost is higher, can greatly reduce the management cost, development cost and failure cost, reduce the design and production man-hours, layout area and so on. As a professional supplier of high-quality power supply and communication interface products, Mornsun offers a variety of communication interface products, including integrated transceiver modules and discrete component parts, so that customers can make flexible choices to meet the needs of various industries.
Integrated isolated RS485/CAN transceiver with built-in power supply
1. Chiplet isolated RS485/CAN transceiver--R4/R5 series
Discrete device solutions often require the selection and procurement of many devices, as well as the control of material conformance. At the same time, the design and verification process is complex, thus leading to an increase in overall development and management costs.
The MORNSUN chip-level isolated RS485/CAN transceiver R4/R5 series, which integrates power isolation and digital isolation, has the advantages of easy to use, convenient management and less board occupation.
Advantages:
Integrated power solution with a refined circuit design
R4/R5 transceiver integrates power isolation and digital isolation with a complete circuit design to achieve power supply isolation and signal isolation, a significant saving in customer layout space.
Withstand voltage up to 5000Vrms, high-reliability design
When communicating between high-voltage devices and low-voltage devices, common-mode interference and isolation safety must be considered, so high isolation is the primary parameter to consider. R4/R5 bus ICs are designed according to industry standards:
1）According to the requirements of the UL1577 standard, the isolation voltage is up to 5000Vrms
2）Human static electricity can reach several thousand volts or more, causing ESD damage to electronic products, bus-pin ESD protection up to 6kV (HBM)/±15kV (contact discharge);
3）The products feature a variety of protections such as short-circuit protection, over-temperature protection, etc., making them reliable solutions.
2. Digital isolators with an integrated isolated DC-DC converter --TDA51S-41HC
Digital isolators with built-in isolated power supply, flexibly combinable with ICs like 485/CAN Bus IC modules or ADC
3. Integrated isolated RS485/CAN transceiver with built-in power supply- module type
MORNSUN communication interface bus products are available in a variety of packages, including Potted and Open Frame types: SMD, DIP8, and DIP24, and are pin-compatible with mainstream products. High-speed types, compact-size types, (single/dual) automatic transceiver types, integrated AC/DC power supply types, etc. are available to meet the needs of various industries.
Chip level isolated RS485/CAN transceiver without built-in power supply
This type of transceiver product integrates digital isolators and signal interface ICs. It can be used with isolated power supplies to increase system reliability. The I/O power supply range supports 3.3V and 5V microprocessors, bus ESD protection up to 15kV (HBM), and baud rates up to 1Mbps.
Interface IC & digital isolator IC
If you keep using the discrete solutions, MORNSUN also has the specific interface ICs and digital isolator ICs for you, which are pin-to-pin compatible with the international mainstream ICs. With a complete and stable supply chain and strong production capacity, we ensure on-time delivery and meet the customers’ high reliability and low-cost requirements.
1. RS485 transceiver
2. CAN transceiver
3. Digital isolator
Summary
As industry demand and technical requirements increase, the associated digital interface transceiver components are also rapidly updated and iterated. Mornsun strives for high efficiency and reliability to ensure superior performance, not only to provide customers in various industries with worry-free and useful power supply products but also to help customers reduce system size and improve system reliability.
