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THVD1450: TIDA-010026, L2 on VCC rail

Genius 15940 points
Part Number: THVD1450
Other Parts Discussed in Thread: TIDA-010026,

Hello,

My customer has a question for TIDA-010026, Robust interface reference design for EnDat2.2 absolute encoders.
This design uses THVD1450 and there is L2 on its VCC rail. What is the purpose of this L2?

  

Regards,
Oba

  • Oba,

    In most cases, an inductor on the power rail is to filter out high frequency noise from an external power supply. Since this is an auxiliary rail that could bring in noise from another environment, L2 is used to filter the power supply pin along with the decoupling capacitor.

    Regards,

  • Hi Oba,

    The BOM file for this reference design (available in the design files on the product page) lists the information for each component used. In this document, L2 is listed as a ferrite bead. These passive components filter out high frequency noise and can be used on a power rail to decrease the noise injected onto (or sourced from) the supply rail. Because RS-485 transceivers regularly switch analog signal rails, sourcing current from Vcc, high-frequency filter methods such as ferrite beads and decoupling capacitors help reduce any noise that may reach (or come from) other devices' supply pins.

    Let me know if you have any more questions.

    Regards,
    Eric Schott