The cc13x0-trm has an ADC Reference section (17.4.8.2 in the pdf I have) which states:
The ADC supports two different internal references, one constant and one relative to VDDS.
The ADC automatically scales down the input signal to be within the reference range. It is possible to disable the scaling, but this requires great care by the user to ensure the maximum ratings in the data sheet are followed. With scaling enabled, the internal fixed reference looks like 4.3 V compared to the actual input level. With scaling disabled, the reference is 1.44 V.
My understanding is that no matter the VDDS level the input voltage can be 0-4.3V when constant reference with input scaling is used (i.e. adc input voltage level can be larger than VDDS).
But the cc1350 data sheet has an Absolute Maximum Ratings section where the table below can be found:
|
Vin Voltage on ADC input |
Voltage scaling enabled |
–0.3 VDDS |
V |
|
Voltage scaling disabled, internal reference |
–0.3 1.49 |
||
|
Voltage scaling disabled, VDDS as reference |
–0.3 VDDS / 2.9 |
||
The information provided in the two documents seem to contradict each other. I'd like to know if I can measure voltage levels above VDDS when the constant reference is used with scaling, and if not what are the consequences?
