PFR856 datasheet by STMicroelectronics

PFR856 Frequently Asked Questions (FAQs)

• What is the recommended operating voltage range for the PFR856?
  The recommended operating voltage range for the PFR856 is 2.5V to 5.5V, although it can operate down to 2.2V with reduced performance.
• How do I ensure the PFR856 oscillator starts up reliably?
  To ensure reliable startup, it's recommended to add a 1kΩ to 10kΩ pull-up resistor between the XTAL1 pin and VDD, and a 1MΩ to 10MΩ pull-down resistor between the XTAL2 pin and GND.
• What is the maximum frequency that the PFR856 can operate at?
  The PFR856 can operate up to 32.768 kHz, but it's recommended to operate it at 32.768 kHz or lower to ensure optimal performance and stability.
• How do I configure the PFR856 for low-power operation?
  To configure the PFR856 for low-power operation, set the PD bit in the Control Register to 1, which will put the oscillator in power-down mode. Additionally, consider using a low-power crystal or ceramic resonator.
• Can I use the PFR856 with a ceramic resonator instead of a crystal?
  Yes, the PFR856 can be used with a ceramic resonator, but it's recommended to use a resonator with a high Q factor (>100) and a load capacitance of 10pF to 20pF to ensure reliable operation.