Type: Posts; User: mtwieg

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  1. Closed: Re: I2C bus - what is maximum bus lenght when working with 100 KHz clock (errorless w

    Very interesting chip, have you ever used it?
  2. Replies

    Closed: Re: Understanding S21 for an unmatched network

    Hi venn_ng, need to be careful when trying to use and interpret s parameters, especially in cases where you're considering putting things on the ports of the network which aren't 50 ohms.

  3. Replies

    Closed: Re: TL494 Doubts about driving NPNs

    To add to previous posts, the first circuit apparently has a fifth winding on the gate drive transformer which is coupled to the output of the final push pull stage. There's a slim chance this could...
  4. [SOLVED]Closed: Re: ORing diodes replacement for high voltage (160V)

    Here's one LT app note that gives some examples:

    This circuit in figure 3 should be applicable to arbitrarily...
  5. [SOLVED]Closed: Re: ORing diodes replacement for high voltage (160V)

    Some sort of comparator with hysteresis would be a good start. Depends on exactly how you want the circuit to behave.

    If you use an isolated supply, you could put all the voltage/current sensing...
  6. Replies

    Closed: Re: Tuned Amplifier in LTSpice

    I've seen very similar issues when doing transient simulations of high-Q circuits in LTspice (though it's likely not an issue particular to LTspice, but numeric solvers in general).

  7. [SOLVED]Closed: Re: ORing diodes replacement for high voltage (160V)

    Sure you can do it, but I don't think anyone makes a dedicated IC which works at such voltages. You'd have to roll your own using an isolated supply and isolated gate drivers. You could try doing it...
  8. Replies

    Closed: Re: Load switch with high gate current drive?

    I've used the LTC7000 as a load disconnect in the past. Unlike parts like the LTC4368, it has a high current gate driver.

    I kinda like betwixt's idea of using an SCR though. Probably simpler to...
  9. Replies

    Closed: Re: Via keepouts under MLCCs and inductors?

    The keepouts are defined in the component footprint, so any 2220 size capacitor will have the keepout by default, regardless of whether it's rated for 5V or 500V, and regardless of what the actual...
  10. Replies

    Closed: Re: Class C amplifier at 5 GHz

    That looks like fairly reasonable behavior for a class C (hard to tell without more context)
    For a class C amp, it takes some minimum amount of input power to cause the transistor to do anything....
  11. Replies

    Closed: Re: RF choke replacement question

    I think you're being a little too cynical. For a dev board, it has to meet performance specs over its full rated bandwidth, and to do that a wideband choke is necessary. I'm betting if you called one...
  12. Replies

    Closed: Via keepouts under MLCCs and inductors?

    I usually have my layouts done by a third party, and they generally insist that no vias ever be placed underneath large capacitors and inductors (not referring to via in pad). See below: the pink...
  13. Closed: Re: Inrush from 48V battery into 9mF of power supply output capacitance

    Eventually the contacts are going to either spot weld to each other, or get so much pitting that their resistance increases severely, or they break. If you fulfill their request, make sure they know...
  14. Closed: Re: Putting a battery on power supply output to help with load transient performanc

    Pretty sure LiFePO4 is 3.2 nominal and 3.6 max, regardless of packaging.
  15. Closed: Re: SMPS design can change polarity and get more current?

    The polarity of that output relative to the other outputs is defined by the transformer windings, so you'd need to replace the transformer. At that point you're basically looking at an entirely new...
  16. Replies

    Closed: Re: three-phase PLL chip

    FvM beat me to it, but your 3 phase PLL is ill-defined, and I doubt such a magic chip exists (for good reason). Pretty much all PLL chips are designed to work with a PFD frequency much greater than...
  17. Replies

    Closed: Re: Class C amplifier at 5 GHz

    Yeah S parameters are basically meaningless for a class C amp. You need to do load and source pull simulations with PSS/HB.
  18. Closed: Re: Putting a battery on power supply output to help with load transient performanc

    Using a battery for load leveling is fine, but you'd be foolish to think you can just treat the battery like a big capacitor by connecting it with diodes and resistors. You need a proper charge...
  19. Closed: Re: Common mode noise is worse in isolated SMPS cf non-isolated SMPS?

    Typically the main source of common mode EMI in a flyback is current injected from the transformer's interwinding capacitance. When the flyback is non-isolated, most of that current will return...
  20. Replies

    Closed: Re: Current cource with LM5145 ?

    The old unitrode controllers are best used with external gate drivers. Generating complementary outputs for a synchronous rectifier is fairly trivial.
  21. Replies

    Closed: Re: Current cource with LM5145 ?

    For something like this, you want a controller with a tracking function, meaning you can change the output by adjusting the reference voltage to your feedback controller. The LM5145 offers such a...
  22. Closed: Re: Need to Find a commercially available Integrated OTA for capacitive loads

    Check out OPA860, OPA861, and LT1228.
  23. Closed: Re: EMI issue in high power DC/AC inverter FCC PART 15B 3M

    A schematic would help a lot to follow your description... also a photo of the PCB/heatsink assembly.
  24. Closed: Re: Which common mode choke has the lowest leakage inductance?

    Bifilar is fine for 48V.

    Wire is so cheap it doesn't make sense to sell it in such small quanities. 100m should be less than 10 Euro.

    0.25mm is used in many ribbon cables, I think. I've used it...
  25. Replies

    Closed: Re: Multistage LNA design queries

    Yes sometimes a single LNA stage doesn't have sufficient gain. But normally this is done by cascading a single stage LNA with a more general-purpose gain block stage, rather than cascading multiple...
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