This application note presents a reference design of a compact isolated CAN module by using isolated transceiver ISO1050 and transformer driver SN6501. Compared to current solutions in the industry, this design has the advantages of easy implementation, high reliability, low EMI, and low cost. The ISO1042 can be used as a performance upgrade to the ISO1050.
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Today, along with the fast popularization of CAN-bus, the application field is more diversified and complicated than before. Un-proper node design causes poor communication, and even one node failure can result in damage to an entire bus, especially in a harsh environment. Therefore, essential protection circuit should be implemented into node design to improve reliability and reduce unnecessary damage. For common design, isolation for digital signal and power is added between the controller and the transceiver. In some applications that require higher ESD protection, TVS should be added in the bus.
The current solutions are either too complicated (for example, digital isolator, CAN transceiver, and isolated power) or too expensive. As a viable solution, the combination of ISO1050 with SN6501, a compact, high-performance and low-cost reference design, is provided.
ISO1050 transceiver is an isolated CAN transceiver with a maximum data rate of 1 Mbps and 4 kV of galvanic isolation. The ISO1050 transceiver meets or exceeds all requirements of the ISO 11898 standard. This device uses capacitive isolation technology (SiO2) for signal path isolation. Compared to inductive and optocoupler type, the main advantage of SiO2 capacitive isolation is high reliability and long-life time expectancy, which benefits from its small aging effect characteristic. With an industry lifetime requirement at 400 V (minimum) working voltage, inductive type has only 8 years while capacitive isolator has a significantly longer lifetime of 28 years.
Due to internal design construction of capacitive isolators, this type of isolator provides almost infinitely high magnetic field immunity. Figure 2-1 describes the quantified magnetic immunity (the field-strength is applied without causing false toggling). Figure 2-1 shows outstanding performance of the capacitive device, which is far beyond the standard of IEC 61000-4-8 and IEC 61000-4-9.
Another benefit of using SiO2 capacitive technology is that it is compatible with standard semiconductor manufacturing processes. Therefore, lower production cost is achieved, thus bringing the lower cost to customer directly.