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Challenges of Embedded Passives

I began attending engineering conferences on integrated passive components around 15 years ago. At that time, there were various schools of thought ranging from integrating resistors, capacitors, and inductors on a simple ceramic chip or chip array, to embedding resistors in the printed circuit board, to bringing multiple passive circuit functions onto the silicon of the IC they were associated with.

In particular, one large OEM gave many presentations showing the feasibility of embedding resistors and capacitors into the PCB (printed circuit board) structure. Their conclusion was that embedding passives into the board would save some amount of cost for resistors and capacitors with somewhat looser tolerances and for circuit designs that had completed prototype validation runs.

Yet today, I still see very little of this type of design happening. This may be a little surprising to some, given that embedded resistors are now able to hold much tighter precision, their cost has gone down, and design for manufacturing has become more advanced with the boundless simulation software programs now available.

However, in my opinion, the increased complexity required in the PCB (or silicon if the passive functions are brought aboard the ASIC), compounded by the fact that discrete commercial passive components are so abundant and inexpensive, means most design engineers simply don't want to deal with the added issues of these more complex boards and ASICs.

I just don't think the benefits outweigh the risks, but this is from the perspective of a passive component manufacturer. I'd be very interested to hear other opinions on the subject.

7 comments on “Challenges of Embedded Passives

  1. Nemos
    May 13, 2011

    “embedding resistors and capacitors into the PCB” What happens if we want to repair or rework a PCB with embedded resistors and capacitors? Doesn't this make the service job very difficult?

    Because most of the engineers they don't think what will happen if something goes wrong after the manufacture process of the product.

  2. Wale Bakare
    May 13, 2011

    It has been come imperative for future electronic design products to face with huge challenges due to an increase in their market demand. So also, while this is about to happen we cant rule out for less expensive  functionable materials to integrate to the design board.

    1 – If embedded passive elements could be the determining factor for a) optimum component performance b) technical processing c) cost effective ie less expensive i could not see why the design engineers should shirk away from adopting more responsibilities.

    2 – Leakage: If concerns about the power leakage could also be brought to a considerable level by developing with high -K materials so as to improve battery consumption, i think it could be worthwhile taking up the challenges  with embedded passives.

  3. Anand
    May 14, 2011

    “Their conclusion was that embedding passives into the board would save some amount of cost for resistors and capacitors”

    @Kory,

     Embeddeding passives will results in higher cost (per unit area) of boards fabricated with embedded passives and possible decreases in throughput of the board fabrication process. Do you still feel this will save cost ?

  4. saranyatil
    May 16, 2011

    Implementating embedding passives should be a technique adopted which will free up the space on the top surface, in turn all other active components can be placed. Especially this can be used in small devices.

    Suppose if we can place capacitor dielectric between ground and power this will become a good filter and also we can connect the capacitor near the active component there by will reduce the number of layers.

  5. Clairvoyant
    May 16, 2011

    Embedded passives are a great idea, however a couple challenges I can quickly think of would be trying to perfect the values of the embedded passives during the design process, and having high tolerances on the board materials in order to get the right values. Also, if there are any manufacturing issues on the PWB's, it would be very hard or impossible to fix on built up PWBs and they would need to be discarded.

  6. tioluwa
    May 16, 2011

    If it's just for the purpose of another great idea, and inovation, why not! Embeddd passives would be awesome.

    However, in a competitive market, alot of issues come up.

    1. will special PCB equipments have to be designed to support embedded passives?

    2. what about the software to design the embedded passives have those been done, tested and perfected? what extra complexities will they bring to the design process.

    3. Has their durability, efficiency and stability been tested?

     

    I think we need all the facts as to what embedded passives really cost both to the manufatuere and to the designer as well.

  7. elctrnx_lyf
    May 23, 2011

    The printed circuit have become much much complex than it is around 15 years ago because of the huge BGA chips and various other signal integrity recommendations that needs to be followed. So may be the inexpensive passives are not an worry to the design houses. If the passives have to embedded all the OEM's need a specific engineers to take care of the effects of it. So we won't see embedded passives in the PCB's.

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