LTC6904

The LTC^®6903/LTC6904 are low power self contained digital frequency sources providing a precision frequency from 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 3V 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:f=2OCT·2078(HZ)/(2-DAC/1024);kHz <f< 68 MHz
 
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.