Crystal Specification of the EZ-USB® HX2™ (CY7C65640A), HX2LP™, and HX2VL™ – KBA87625

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Question: What is the required crystal specification of the EZ-USB® HX2™ (CY7C65640A), HX2LP™, and HX2VL™?

 

Answer:

For HX2 (CY7C65640A): Cypress recommends a load capacitance between 20 pF and 33 pF when a 24 MHz ± 0.05 percent crystal is used in the HX2 design.

For HX2LP: A 24 MHz ± 0.05 percent crystal can also be used in the HX2LP design, but please consider the following:

  •   A 12 pF rating on the crystal
  •   Parallel resonant
  •   12 pF capacitors for load caps
  •   500 μW drive; the 500 μW value is the power that is driven into the crystal. This rating is typically overlooked, with designers using 100 μW or 10 μW, which is not allowed.

For HX2VL: Refer to the Clock Requirement section of AN72332 – Guidelines on System Design using Cypress’s USB 2.0 Hub (HX2VL).