ltspice nmos4 and pmos4

Started by Michael Robinson in sci.electronics.design11 years ago 3 replies

I have to simulate a CMOS circuit and I am going to try it in LTSpice. The dialog box where you can put in parameters for a mos4 device has no...

I have to simulate a CMOS circuit and I am going to try it in LTSpice. The dialog box where you can put in parameters for a mos4 device has no place to enter parasitics! That means I need a subcircuit. To save time is there anyplace where I can grab subcircuits for nmos4 and pmos4 devices? That would save a lot of time, I can just change the values.


Circuit for Randomized Pulse Width Modulation

Started by Robert Martin in sci.electronics.design4 years ago 43 replies

I have a CD4060 outputting a 5Vpp 4Hz (4 hertz) square wave at 50% duty cycle. How can I randomly pulse width modulate this so that when a...

I have a CD4060 outputting a 5Vpp 4Hz (4 hertz) square wave at 50% duty cycle. How can I randomly pulse width modulate this so that when a low pass filter is added a constantly changing, "wave-like" arbitrary waveform will be produced? I would prefer analog or CMOS IC's, not a microprocessor, and minimum parts count. The "randomness" does not need to be true but only a reasonable ...


discrete JFETs vs CMOS analog switch

Started by Adam Seychell in sci.electronics.design2 years ago 29 replies

I need a switchable 0 /40dB attenuator for a 10Hz-20MHz 1Vp-p signal into a buffer amplifier (10k|3pF input loading). First I thought of using a...

I need a switchable 0 /40dB attenuator for a 10Hz-20MHz 1Vp-p signal into a buffer amplifier (10k|3pF input loading). First I thought of using a SPDT analog switch and resistor divider, but even 'low capacitance' devices come with 15~20pF capacitance on the common pin and have poor off isolation for my purpose. in --.--SW1--.--> to buffer | | 1kR | |--


RRIO LV jellybean

Started by bitrex in sci.electronics.design3 years ago 4 replies

My go-to quad lately for higher-performance low-voltage tasks has been the OPA4332. But it's a little pricey for some more pedestrian...

My go-to quad lately for higher-performance low-voltage tasks has been the OPA4332. But it's a little pricey for some more pedestrian jobs. Is there a CMOS RRIO down to ~2 volts equivalent of the LM324 that you use? The TSV99x is fast, low voltage (2.5 vs 1.8, though), and cheaper than the OPA4332. But not unity-gain stable. I'm not clear if an amp that's only stable for gain > = 4 or


insane flipflop measurements

Started by John Larkin in sci.electronics.design6 years ago 46 replies

I'm doing a fast thing and thought I might go all CMOS, instead of traditional expensive ECL. We have the Fairchild NC7SV74 tiny...

I'm doing a fast thing and thought I might go all CMOS, instead of traditional expensive ECL. We have the Fairchild NC7SV74 tiny logic flipflop in stock, 16 cents each. I thought I'd play with one. Here are the rise and fall times at the Q output, 3.3 volt supply: https://dl.dropboxusercontent.com/u/53724080/Parts/Logic/NC7SV74_2.JPG That fall time is amazing, but the rise time is h...


Single Button On/Off Circuit with Delay

Started by Ricketty C in sci.electronics.design2 years ago 15 replies

I'm trying to figure out a way to design an On/Off circuit that uses very little power when off and requires holding the push button for two or...

I'm trying to figure out a way to design an On/Off circuit that uses very little power when off and requires holding the push button for two or three seconds before it accepts the change. A pair of CMOS gates/inverters can provide the low power two state circuit and a push button connected with a simple capacitor/resistor arrangement will default to off on power up and allow toggli


How to drive this huge LED matrix board?

Started by Jan Panteltje in sci.electronics.design9 years ago 14 replies

Scored some of these today, 7Euro50 each : http://www.baco-army-goods.nl/aanbiedingen/ledmatrix-bord-fds132.html Front: ...

Scored some of these today, 7Euro50 each : http://www.baco-army-goods.nl/aanbiedingen/ledmatrix-bord-fds132.html Front: http://www.panteltje.com/pub/matrix_display_front_side_IMG_4118.JPG Component side, lots of 5 V CMOS, processor, optical interfaces: http://www.panteltje.com/pub/matrix_display_component_side_IMG_4119.JPG Would make a nice Merry Christmas running text. Anybod...