Nuvoton Crystal-less USB Solution – The Best Promoter for Compact and Slim Products
Data Source : Deputy Director Jason Tu, Microcontroller Marketing & Application Division, Nuvoton Technology Corporation
To ensure an accurate communication, USB products require a precise and stable clock source. The clock source should be free from the temperature and electrical interference to avoid any communication failures or crashes. When designing the product, developers usually use external crystals to generate a precise and stable clock source. At least 1 crystal and 2 load capacitors are required in the design; however, these components often result in a less than ideal yield during the PCBA process. When assembling the capacitor, the cold solder tends to cause start-oscillation failures. Moreover, the use of external crystal requires more footprints on the PCB and thus increases the difficulty when designing the end product.
To solve the problems caused by the external crystal as well as correspond to the compact and slim modern electronic products, Nuvoton developed a crystal-less USB solution which has high immunity for power noise and is capable of real-time synchronous calibration with a built-in precise 48 MHz high precision and high speed RC oscillator. With this solution, the customer does not need to consider the application circuit of external crystal when designing the circuit. It can save the cost of 3 components (1 crystal and 2 capacitors), prevent the potential defects during the process, and thus enhance the customer’s USB product quality. Moreover, the 2 pins which are originally for crystal soldering can be designed flexibly for other external designs or I/O pins to further improve design flexibility.
Nuvoton’s crystal-less USB solution, with the proprietary high immunity for EFT test, ensures the customer’s USB end products will fully pass the electrical fast transient (EFT) test. This solution has been massively applied to related USB products such as gaming mice, keyboards and controllers.
Related MCUs of Nuvoton Crystal-less USB Solution
Example of Nuvoton crystal-less USB solution application - Gaming mouse
Nuvoton solution feature
-Supports a report rate of 1000 times/sec; respond without delay
-Supports crystal-less USB transfer
-Provides SPROM; total protection of the developer code
-Supports 24-channel PWM ( NUC121/125 ); can connect up to 8 RGB LEDs to create a splendid light effect
-Supports VAI (Voltage Adjustable Interface, NUC125); can connect to the serial port of 1.8V sensor