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  1. D

    Time-domain simulation for frequency controlled resistor

    I'm a bit confused by the original statement that you "have a resistor that is defined as: R=0.2*f" because that's not a resistor and I'm curious how you came to have (implying physical possession) such a thing, which I would not think exists. I'm wondering whether it is in fact an inductor...
  2. D

    [General] DC Motor Interfacing using 8051

    Certainly an avalanched back-diode will be a source of instantaneous current once the FET turns on, unlike the leisurely inductor current ramp you probably have planned on for the motor load. That means PWM is not producing a controlled switch current in the MOSFET, but whatever the...
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    Accelerometer not in stock anywhere?

    I have no reason to agree or disagree (though absolutes tend to fail) but have seen multiple older accelerometer designs go EOL as manufacturers drive their customers to the newest, highest-feature designs; away from analog outputs to serial, etc. You might begin with ST's product life cycle...
  4. D

    IGBT discontinued

    Every device has a DC safe operating area and a duty cycle dependent SOA and a one-pulse (spec width) SOA. This is what you are violating by some combination of device, control and workpiece attributes. You can fix one of these by catalog shopping.
  5. D

    SMPS unstable output

    From the narrow duty cycles shown I wonder if this is a min on time / max on time problem that is "breaking the loop" (or just "winding it up"). The character of instability holds clues. A small signal instability ought to look like a sine wave oscillation, while "limit cycle" issues will look...
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    Is Web Development is a good career choice?

    Purely from an economics point of view I'd say "no". I get multiple spams a day for web and mobile app services, the local ads are full of same. Supply and demand seem out of balance and content creators get paid squat in that kind of environment. If you will succeed it will be on the...
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    Time-domain simulation for frequency controlled resistor

    A long time ago in a galaxy far, far away I made a veriloga frequency-to-voltage model. You could use that to control a voltage dependent resistor model. Or you could combine the two all in a veriloga bundle. The frequency sense was crude, just a zero crossing math, latest minus previous...
  8. D

    Spectre : Invalid component name was given as value of parameter

    I don't see where these "agnt" instances are, or what they are. The schematic shown is not the "GNTAna.scs" (subcircuit?) from which the errors are thrown. If they're "A sources" and those "parameters" looking for "component name" arguments are actually such (like cccs wants a device, not...
  9. D

    I only have the library (from the picture) for my Hspice. Should I use another library for designs operating in subthreshold i.e (0.4V to 1V)?

    You should look at the next layer - what VT options are there, can you do everything you need to with a (say) BVdss=1.8V, VT=0.4-0.6V device? I'd suspect that things like output drive and input-output delay would not be very good or consistent when VT variability straddles the nominal supply...
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    MOS resistor linearization technique

    I think a fundamental problem will be small signal vs large signal behavior. Large signal will expose the FET nonlinearity as a loss / distortion component, more clearly than AC small signal analysis, unless the "forward" and "feedback" resistors are kept to identical operating points (incl...
  11. D

    IGBT discontinued

    If this is a capacitive sealing type application, the plastic film itself may be part of the problem - flaws, pinholes etc. present a lower breakdown and there's where an arc will start, and then the IGBT sees more than designed current. Now you might ask, where is the protection against such...
  12. D

    Can't I make parametic sweep at PSPICE?

    Perhaps make DC={VOFF} as well, so the various analyses run with the same basis?
  13. D

    Comparator offset calculation

    There is an error term in the transient ramp offset voltage measurement scheme. It involves the ramp dV/dt and the low-overdrive propagation delay (which itself depends on input dV/dt, the slower you go, the lower the overdrive and the longer the delay). Your "measured" Vio will include ramp...
  14. D

    How to improve the performance of the circuit?

    "The" circuit? What circuit? You're not going to, for example, "improve" the high voltage switching performance of anything, by going to 5nm (from where?). You might improve speed and transistors per mm2. You might or might not improve power depending on the balance of trade-offs made for you...
  15. D

    intresting way to bias an RF amplifier

    The drain voltage would depend on the load, the load is the input bias current of the amplifier. Seems peculiar, to drive the PMOS with a not-ground voltage for turnon if this is supposed to be a "STFU" switch. But we'd want a datasheet link for the amplifier if we were to make sense of a...
  16. D

    Looking for 74x & 4xxx series datasheets

    On the other hand many major mfrs have started to "disappear" obsoleted products' collateral from their web sites. I like to collect old-timey databooks fro as early as possible as the manufacturers were a lot more forthcoming with design and physical details, back when engineers ran the...
  17. D

    The ion implantation allows for greater flexibility in obtaining doped layers?

    With ion implantation you have control over the initial depth of the dose; for deposited dopant you can only have Z=0 initially. With ion implant you can have Zpk=-0.1 or -1u depending on accelerating voltage and ion charge (triply ionized boron picks up 3X the energy from the accelerating...
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    DC Motor PWM Circuit Doesn't Work When Controller And Motor Share Voltage Source?

    It might be less about current than its "chopping". The motor -drive- might be what needs a separation of signal / data supply and ground from electromechanical. Have you put a 'scope to the supply to see how filthy?
  19. D

    intresting way to bias an RF amplifier

    The "1V" may be a rough OP value that represents a more complex circuit's imposed control voltage such as a closed loop active bias scheme.
  20. D

    "NaN" error on power supply schematic.

    Often this is due to a built-in calculation in a "callback" that figures a model property based on instance (symbol) properties. If any of them are not-set or fail to evaluate due to insane values (like a "/0" from a defaulted empty field) then NaN is what you get. So I'd look real carefully...

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