Analog Devices Inc./Maxim Integrated

The LTC6903/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 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.ApplicationsPrecision Digitally Controlled OscillatorPower ManagementDirect Digital Frequency Synthesis (DDS) ReplacementReplacement for DAC and VCOSwitched Capacitor Filter Clock

The LTC6906 is a precision programmable oscillator that is versatile, compact and easy-to-use. Micropower operation benefits portable and battery-powered equipment. At 100kHz, the LTC6906 consumes 12µA on a 3.3V supply.A single resistor programs the oscillator frequency over a 10:1 range with better than 0.5% initial accuracy. The output frequency can be divided by 1, 3 or 10 to span a 100:1 total frequency range, 10kHz to 1MHz.No decoupling capacitor is needed in most cases, yielding an extremely compact solution occupying less than 20mm2. Contact LTC Marketing for a version of the part with a shutdown feature or lower frequency operation.The LTC6906 is available in the 6-lead SOT-23 (ThinSOT) package.APPLICATIONSLow Cost Precision Programmable OscillatorRugged, Compact Micropower Replacement for Crystal and Ceramic OscillatorsHigh Shock and Vibration EnvironmentsPortable and Battery-Powered EquipmentPDAs and Cellular Phones