Analog Devices LTC6904 Product Info

• 1kHz to 68MHz Square Wave Output
• 0.5% (Typ) Initial Frequency Accuracy
• Frequency Error <1.1% Over All Settings
• 10ppm/°C Typical Frequency Drift Over Temperature
• 0.1% Resolution
• 1.7mA Typical Supply Current (f < 1MHz, V_S = 2.7V)
• 2.7V to 5.5V Single Supply Operation
• Jitter <0.4% Typical 1kHz to 8MHz
• Easy to Use SPI (LTC6903) or I²C (LTC6904) Serial Interface
• Output Enable Pin
• –55°C to 125°C Operation
  
• MS8 Package

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.

Applications

• Precision Digitally Controlled Oscillator
• Power Management
• Direct Digital Frequency Synthesis (DDS) Replacement
• Replacement for DAC and VCO
• Switched Capacitor Filter Clock