ZHCSVJ2I August 2007 – December 2024 CDCE937 , CDCEL937
PRODUCTION DATA
When the CDCEx937 is used as a crystal buffer, crystal oscillator start-up dominates the start-up time compared to the internal PLL lock time. Figure 9-4 shows the oscillator start-up sequence for a 27MHz crystal input with an 8pF load. The start-up time for the crystal is in the order of approximately 250μs compared to approximately 10μs of lock time. In general, lock time is an order of magnitude less compared to the crystal start-up time.
Figure 9-4 Crystal Oscillator Start-Up vs PLL Lock Time