AZKN6129P - Key Parameters to Consider When Selecting CAN Bus Transceivers for E-Bike Systems

With the global emphasis on health and environmental sustainability, electric-assisted bicycles (E-Bikes) have gained tremendous popularity and have become an important means of transportation that combines exercise, recreation, and daily mobility. Thanks to continuous advancements in battery technology, E-Bikes now offer longer riding range and faster charging speeds, significantly improving the overall riding experience. 

In addition, the integration of intelligent features has become a major highlight of modern E-Bikes. Functions such as built-in GPS, Bluetooth connectivity, and smart control systems enable real-time monitoring, positioning, and navigation while enhancing overall safety. Furthermore, lightweight designs and the expansion of charging infrastructure are accelerating the adoption of E-Bikes as a mainstream option for short-distance urban commuting. 

Taking Taiwan’s smart city initiative as an example, the increasing deployment of YouBike 2.0E electric-assisted bicycles—and their utilization rate being nearly twice that of conventional bicycles—clearly indicates that modern users prefer energy-efficient, lightweight solutions suitable for short-distance transfers. This trend not only helps alleviate traffic congestion but also contributes to carbon emission reduction, aligning with the future direction of urban development. 

However, when selecting a CAN bus transceiver for E-Bike applications, the following key parameters should be carefully considered: 

A. Package 

With the trend toward miniaturization in E-Bike designs, PCB sizes for motor controllers and display units continue to shrink, leaving limited space for CAN bus-related circuitry. Therefore, DFN-packaged CAN bus transceivers are recommended. For example, a DFN8 package with dimensions of only 3.0 mm × 3.0 mm can significantly save PCB space and provide greater layout flexibility. 

B. Fault Voltage

Typical E-Bike system voltages include 36 V (with a maximum of 42 V) and 48 V (with a maximum of 54.6 V). As CAN bus connectors become increasingly compact, accidental contact between CANH/CANL and DC power rails may occur, leading to overvoltage damage. Consequently, CAN bus transceivers used in E-Bike systems are often required to support a fault voltage of at least 42 V, with 70 V being highly desirable to ensure compatibility with both 36 V and 48 V systems. 

C. VIO Voltage Translation 

With advanced semiconductor processes, MCU operating voltages have largely shifted from 5 V to 3.3 V, and even down to 1.8 V. CAN bus transceivers equipped with a VIO pin allow flexible I/O voltage matching. By directly connecting the transceiver I/O to 3.3 V or 1.8 V, designers can eliminate additional level-shifting components, achieving both space and cost advantages, as shown in Figure 1. 

D. ESD / EOS Robustness 

Compared to typical consumer electronics, E-Bike products are more susceptible to electrostatic discharge (ESD) during riding and higher-energy electrical overstress (EOS) events caused by charging cable insertion and removal. To reduce field failure and return rates, ESD specifications for E-Bike applications are often more stringent, sometimes exceeding IEC 61000-4-2 Level 4 requirements of 8 kV contact and 15 kV air discharge. 

E. Temperature Range 

Since E-Bikes operate outdoors for extended periods, thermal requirements are more demanding. It is recommended that designs support operating temperatures up to 125°C to minimize the risk of abnormal system behavior. Failure to meet temperature requirements may result in product damage, increased repair rates, and, in severe cases, loss of consumer trust and brand reputation.