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TMS320VC5409A-120 and -160 CVDD Operating Voltage Compatibility at 120MHz and Lower

I'm currently working on replacing the now obsolete TMS320VC5409PGE100 with either the TMS320VC5409APGE12 (-120MHz) or the TMS320VC5409APGE16 (-160MHz) DSP in a legacy product.  I would like to specify both the -120 and -160 parts as compatible drop-in replacements but I do see the CVDD requirements differ as shown in Table 5.2 from page 53 of the TMS320VC5409A Data Manual SPRS140G with 1.6V for the VC5409A-160 and 1.5V for the VC5409A-120.

Our product will only requires the DSP to operate at 100MHz so the question becomes can the VC5409A-160 be operated at the same CVDD of 1.5V nominal as the VC5409A-120 if its operated at 120MHz or less? I presume that the -160 is just faster silicon that's higher on the production process normal curve than the -120 but wanted to verify with TI.



  • Hi Jesse,

    It sounds reasonable that you can operate the -160 device at < 120MHz with the CVDD of 1.5V instead of 1.6V.

    TI does bin parts by speed grade, and to operate at the higher speed (160MHz) CVDD must be increased from 1.5V to 1.6V.

    Let me circle this around internally since the datasheet is a legally binding document, and it clearly states min CVDD for the -160 part is 1.55V.

    Alternately, you could operate the CVDD at 1.6V and meet the datasheet requirements for both -120 and -160 variants.

    CVDD Device supply voltage, core (VC5409A-160) 1.55 1.6 1.65
    CVDD Device supply voltage, core (VC5409A-120) 1.42 1.5 1.65


  • Hi Mark,

    Thank you for the reply. Running at 1.6V is probably an acceptable compromise (we're not power constrained) but I'll have to pay closer attention to the tolerance of the CVDD supply. I'll wait and see what you find out internally.