10.2.1 Design Requirements
In a typical application, the following design requirements or parameters should be considered to implement the overall clock solution:
- Device initial configuration: Host programmed (MCU or FPGA) or factory pre-programmed.
- Device start-up mode and serial interface. Typically, this will be EEPROM + I2C or SPI mode.
- XO frequency, signal type, and phase noise or jitter
- TCXO frequency and stability if any of the following is required:
- Standard-compliant frequency stability (such as SyncE, SONET/SDH, IEEE 1588)
- Lowest possible close-in phase noise at offsets ≤ 100 Hz
- Narrow DPLL bandwidth ≤ 10 Hz
- For each PLL domain, determine the following:
- Input clocks: frequency, buffer mode, priority, and input selection mode
- Output clocks: frequency, buffer mode
- DPLL loop mode, loop bandwidth, and market segment
- DCO mode or Zero delay
- Input clock and PLL monitoring options
- Status outputs and interrupt flag
- Power supply rails