说明：  1kHz 至 68MHz 串行端口可设置振荡器
(The LTC® 6903/LTC6904 are low power self contained digital frequency sources providing a precision frequency 1kHz to 68MHz, set through a serial port. The LTC6903/LTC6904 require no external components other than a power supply bypass capacitor, and they operate over a single wide supply range of 2.7V to 5.5V. The LTC6903/LTC6904 feature a proprietary feedback loop that linearizes the relationship between digital control setting and frequency, resulting in a very simple frequency setting equation: Where OCT is a 4-bit digital code and DAC is a 10-bit digital code. The LTC6903 is controlled by a convenient SPI compatible serial interface. The LTC6904 uses an industry standard I2C compatible interface. U.S. Patent Numbers 6342817 and 6614313)