This thread has been locked.
If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.
CDCE913: Disapperring Input clock
Part Number: CDCE913
We are using the CDCE913 to generate a 27MHz output from a 10MHz input. The 10MHz comes from a GPS receiver and what we are finding is that if the 10MHz is not connected when the unit powers up and the 10MHz is connected afterwards the CDCE913 is producing unstable clocks. We have tried reprogramming the CDCE913 when in this state and it does not change. Have tried setting the PWDN bit and putting the dividers into reset and then reprogramming but it is still stuck in this state. Only a power cycle (with the 10MHz attached)will recover it to producing a stable 27MHz. We are not using any of the spread spectrum options.
Can you try writing all registers after the reference is connected?
Clock and Timing Systems & Applications
To view training videos on Clock and Timing Solutions please visit TI Precision Labs
More information Clock and Timing System products: http://www.ti.com/clock-and-timing/overview.html
We are glad that we were able to resolve this issue, and will now proceed to close this thread.
If you have further questions related to this thread, you may click "Ask a related question" below. The newly created question will be automatically linked to this question.
In reply to Hao Z:
Yes this is what I have tried. And have tried putting setting the PWDN bit first before reprogramming and still get the unstable clocks.
In reply to Gary Morrison:
Normally all you need to do is to trigger a PLL re-calibration. This is typically done by a recal bit, a software reset bit or a PDN/RESETN pin. Unfortunately I didn't find any register or pin that can trigger a recal.
Right now the only other way that I can think of is to change the PLL feedback divider (for example, N divider) to some other value then change it back in order to force a calibration, but I'm not sure if it'll work.
All content and materials on this site are provided "as is". TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with regard to these materials, including but not limited to all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement of any third party intellectual property right. No license, either express or implied, by estoppel or otherwise, is granted by TI. Use of the information on this site may require a license from a third party, or a license from TI.
TI is a global semiconductor design and manufacturing company. Innovate with 100,000+ analog ICs andembedded processors, along with software, tools and the industry’s largest sales/support staff.