Part Number: ADC12DJ5200RF
Our question is about power sequencing of ADC12DJ5200RF. In data sheet (page 154) there is recommendation to use common 1.1VDC regulator for analog voltage VA11 and digital voltage VD11. Sometimes it’s not convenient because VD11 power consumption can be significantly bigger compare with analog voltage VA11 (for example, Power mode 5, VA11 has current consumption 845mA, VD11 2672 mA). The digital power can creates noise on analog voltage even choke isolation. How critical is the requirement to use common voltage regulator? How big can be difference between VD11 and VA11 during power up/down procedure? In eval board for ADC12DJ5200RF TI use different approach: switching regulator for VD11 and switching regulator with following LDO for VA11. This solution reduce power consumption on VD11 but probably has difference between this two voltages during power up/down. Thanks.
I apologize if I am mis-understanding the question, but it sounds like you would like a recommendation for using the same power supply domain of +1.1V for both VA11 and VD11?
Please confirm and I can get back with you on details.
High Speed Converter Group
Texas Instruments Inc.
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 Rob Reeder:
I datasheet for this chip TI recommend use one 1.1V power supply for VA11 and VD11, but in eval board for ADC12DJ5200RF TI use different approach: switching regulator for VD11 and switching regulator with following LDO for VA11.
Question is were is correct, or both solutions can be used
In reply to Sergey Konshin:
You have two options, use the approach in the current EVM's power supply design. It is proven and a robust design.
Or, we have just proven out a new "low noise" switcher design that will also work for you. The switcher is about the release.
If you are interested in this design please let me know and I will post the schematics for you to use. This will give you smaller size and better efficiency.
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.