TMS320F280049C: If COMPH and COMPL in a same CMPSS module could work as two separately comparator parts?

Rayna Wang

Hi Expert,

I'd like to make sure that if COMPH and COMPL in a same CMPSS module could work as two separately comparator parts, in other word, if the CMPx_HP and CMPx_LP could connect different signals at the same time?

However, in F280049 TRM, it seems CMPx_HP, CMPx_HN, CMPx_LP, CMPx_LN are connect with a same pin.

Could you help to comment this? Thanks!

over 6 years ago

0 Frank Ankapong over 6 years ago

TI__Mastermind 28275 points

Hi Rayna,

Yes, COMPH and COMPL in the same CMPSS module can be used independently on F28004x. They aren't connected to the same pin. Below snapshot shows the 4 pins COMPH and COMPL of CMPSS1 can connect to.

0 tlee over 6 years ago

TI__Guru 62975 points

Rayna,

Also keep in mind that there can be some cross-disturbance in the DAC output voltages when a comparator trips:

-Tommy

0 Rayna Wang over 6 years ago in reply to tlee

TI__Expert 3680 points

Hi Tommy,

Do you mean that "CMPSS DAC output" is connected with negative input of the comparator, when trip occurs or DAC value changes, the negative reference voltage value will be disturbance in -100 to 100LSB range?

Best Regards

Rayna

0 Frank Ankapong over 6 years ago in reply to Rayna Wang

TI__Mastermind 28275 points

Rayne,

That is correct. COMPDACH and COMPDACL share some components so a trip or change on one will induce disturbance on the other. This means if COMPH trips or COMPDACH's value is changed, it will temporarily disturb COMPDACL's output for a max time of 200ns with max magnitude of -/+100LSBs.

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TMS320F280049C: If COMPH and COMPL in a same CMPSS module could work as two separately comparator parts?