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LTC2986 Direct ADC Measurements


I have a couple of questons about the direct ADC mode of LTC2986. Please take care of this case.

- What is the maximum sampling  speed of internal 24 bit ADCs in the direct ADC mode?

- How can I know conversion start and finish in the direct ADC mode? I can know those by reading any register value?



  • Hi Kazu, 

        The maximum sampling speed of the LTC2986 is fixed for power line rejection. It is about 6Hz when in the default 50/60Hz mode. It will be slightly faster when set for 50Hz rejection only, and slightly slower for 60Hz only. Please see the tables in page 4 of the datasheet as well as page 75 for 2 and 3- cycles modes. Direct ADC is always a 2-cycle mode. 

        Conversion start/finish can be monitored by watching the INT signal (pin), as well as watching the Command status register (address 0x000) which will change from 0x80 during a conversion (start bit = 1, done bit = 0) to 0x40 when finished (start bit = 0, done bit = 1). Please see page 17-21 of the LTC2986 DS for more info.