AD976断电

Hi Mlang ,

Thank you for your inquiry please be so kind as to type all your replies to this thread in English so our engineers may assist you.

Regards,
Jo

Hi Mlang ,

To answer your question, no. You cannot put a signal at the input when you do not have the right parameters and the right sequencing in powering up AD976. Please refer to the absolute maximum rating section of its datasheet (page 5) in determining the right sequencing. And please take note that you should consider what is on the specifications table (page 3 to page 4) for the right parameters to optimize the performance of the device.

Based on the image attached above, you should power up AD796 with important parameters such as analog supply voltage (Vana) and its digital input voltage (Vdig) so that the device would work properly; and so that you can put an input signal.

Moreover, you can refer to the blog attached below, which is at the engineer zone to further understand how to power up your sar adc in the right sequence: 
How To Sequence Your SAR ADC Power Supply - EngineerZone Spotlight - EZ Blogs - EngineerZone (analog.com).

Regards,
Jo

Thanks for the guidance, I still need help with the following issues.  Currently, I use the AD976 chip in my project.  Since the board needs a primary backup, the power supply of the AD976 chip has neither analog 5v nor digital 5v power, will the input voltage signal of the chip cause damage to the chip?  In addition, when the chip is only powered by an analog 5V power supply, if a voltage signal is input at the input of the chip, will it cause damage to the chip?  Because I'm using it this way in my current project, I'm concerned about design flaws.  If not, in the case of hot or cold backup, how can I keep the chip in a healthy working state to ensure that it is not damaged unnecessarily?

Hi Mlang ,

Here are my insights for your concerns:

1. Yes. The chip might be damaged if you put an input signal without supply voltage,  analog and digital. And without proper power up sequence for the analog and digital supply. On the other hand, if ever the chip is not damaged, it still might work but the output might have errors to its accuracy. It will not give you precise data.
2. Yes. If you have an analog supply, yet you have not configured the logic supply. Then it might damage the chip if you put an input signal.

So to have an optimize configuration for a precise data. You should power up the device in its proper power up sequence. Please refer to the absolute maximum ratings section for the proper sequence configuration.

And please refer to this blog, How To Sequence Your SAR ADC Power Supply - EngineerZone Spotlight - EZ Blogs - EngineerZone (analog.com), for your reference in powering up AD976. Please let me know if ever this will help you.

Regards,
Jo

Thank you, your answer helped me a lot

Thank you, your answer helped me a lot