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What is the usage of SDFM(Sigma Delta Filter Module) in TMS320F28377D

Other Parts Discussed in Thread: TMS320F28377D, ADS1204, ADS1209, AMC1204


I`m watching to the TMS320F28377D Technical Reference Manual.

It`s a amazing device. :)


By the way, what is the usage of SDFM(Sigma Delta Filter Module)?

I almost understand about that peripheral`s function, but I don`t know where it use.


In manual,

"SDFM is a four-channel digital filter designed specifically for current measurement and resolver position decoding in motor control applications."


But SDFM is needed bit stream, didn`t it?  Then, block diagram is

Is it right?

Please answer this.

Thank you.


And Happy new year!


  • Hi,

    You are correct.  The 'Bit Stream Generation IC' you describe is called a Sigma Delta Modulator.  TI has several different sigma-delta modulators in its portfolio (ADS1204, ADS1209, AMC1204, etc) and these work with the F28377D device.  

    The ability to cross isolation boundaries cheaply is one of the major reasons to consider sigma-delta sensing.  This is because it is much simpler to cross isolation with digital signals, and is in several modulators built in. 

    For example in your block diagram above:
    if the F28377D controller was isolated from the power portions of the board (and therefore what it needed to sense, etc), a AMC1204 sigma-delta modulator could be placed on the power side of the board.  The modulator would create the bit stream and isolate it.  This would then connect up to the F28377D SDFM module.

    The datasheet and TRM for the device will give more detailed information.

    Thank you,