There is no mentioning about supply sequence into ADS8328 datasheet. Could you please confirm there is no such requirement? Can I apply only VA and REF without VBD? Can I apply only VBD without VA and REF? Can I apply only VBD and VA without REF? Can I apply only REF without VBD and VA? Can I apply only VBD and REF without VA? Can I apply only VA and VBD and REF? Regards, Jovanco
There is no mentioning about supply sequence into ADS8328 datasheet.
Could you please confirm there is no such requirement?
Can I apply only VA and REF without VBD?
Can I apply only VBD without VA and REF?
Can I apply only VBD and VA without REF?
Can I apply only REF without VBD and VA?
Can I apply only VBD and REF without VA?
Can I apply only VA and VBD and REF?
Regards,
Jovanco
Jovanco,
There is not a strict power up sequence restriction between the analog voltage (VA) and the digital voltage (VBD). You do not want to apply the reference voltage until the analog and digital voltages are powered up and stable. TI parts have built in diode protection on the input pins, digital pins, and analog input pins. If you apply a signal to the reference pin (input pin), then the ADC will attempt to power itself through the ESD protection diodes.
To answer your questions:
Can I apply only VA and REF without VBD? I would not recommend this. Make sure that VA and VBD are powered before or at the same time as the reference voltage. Can I apply only VBD without VA and REF? Yes, but the part will not be functional. Can I apply only VBD and VA without REF? Yes, but the ADC needs a reference voltage in order to properly convert. Make sure you apply a REF after to use the ADC when converting. There is no restriction as to if you bring up the digital or analog voltage first. It is just important that they are both brought up. Can I apply only REF without VBD and VA? No. See above. Can I apply only VBD and REF without VA? I would not recommend this. Make sure that VA and VBD are powered before or at the same time as the reference voltage. Can I apply only VA and VBD and REF? Yes. You can bring up the three supplies at the same time without any issues. You need all three supplies in order to have the ADC properly powered. Regards, Tony Calabria
I would not recommend this. Make sure that VA and VBD are powered before or at the same time as the reference voltage.
Yes, but the part will not be functional.
Yes, but the ADC needs a reference voltage in order to properly convert. Make sure you apply a REF after to use the ADC when converting. There is no restriction as to if you bring up the digital or analog voltage first. It is just important that they are both brought up.
No. See above.
Yes. You can bring up the three supplies at the same time without any issues. You need all three supplies in order to have the ADC properly powered.
Tony Calabria