The TI analog to digital converter, ADS8504IBDW is used in an application where the device is connected to use the internal voltage reference. In the datasheet, there is a note that states:
(8) The internal reference may not be started correctly beyond the industrial temperature range (-40 Deg. C to 85 Deg. C), therefore use of an external reference is recommended.
This device is a direct upgrade for the ADS7804 which was previously in the design. The ADS7804 does not have a similar note. It may be possible for the device to exceed this temperature range in the application.
Can someone at TI to elaborate on that note, specifically the following questions please?
The latest datasheet I find on the TI site is dated 2007. Has there been any updates to the datasheet since then?
Is the temperature of -40 Deg. C to 85 Deg. C an ambient temperature or an equivalent device junction temperature?
At approximately what temperature does the reference fail to start up?
What exactly is it about the reference that causes it to not start up? What type of reference is it that it will not start up?
What is the different between the ADS7804 and ADS8504 references such that one works over a wider temperature and one does not?
Under the REFERENCE section of the datasheet, it also talks about adding the external reference to Pin 5, but pin 5 is AGND2. I assume this should be pin 3, the REF pin. Is the datasheet incorrect here?
Is there a pin for pin compatible device in TI’s lineup that is suggested for upgrading to from the ADS8504 which does not have this issue?
There is a 16-bit equivalent ADC, the ADS8515 which has a similar note. Does this part have a similar reference as the ADS8504 device and therefore the same issue?
