guard rings

Started by Anonymous in sci.electronics.design2 years ago 26 replies

Some schottky diodes have a PN junction in parallel, a "guard ring" that acts like a parallel zener to improve ESD specs, and may help with the...

Some schottky diodes have a PN junction in parallel, a "guard ring" that acts like a parallel zener to improve ESD specs, and may help with the fab somehow. That's OK, but at high currents the PN diode can turn on, and it's slow to turn off and can even act like a step-recovery diode. I wonder if there is a way to tell, from the data sheets, if there is a guard ring. VI curve? CV curve? ES...


Schottky diodes for RF application

Started by amal banerjee in sci.electronics.design3 years ago 3 replies

Could someone here shed some light on this ? I am experimenting with envelope detection at RF frequencies with SPICE. The mixer is a simple...

Could someone here shed some light on this ? I am experimenting with envelope detection at RF frequencies with SPICE. The mixer is a simple SPICE B signal source as B0 3 4 V(1)*V(2) where 1, 2 are the nodes at which the two signal sources are attached. THe mixer output is fed into a Schottky diode(1N5818, BAR42 etc.,) and a shunt capacitor is attached to the Schottky diode cathode. ...


Bipolar transistor bias question

Started by billbowden in sci.electronics.design6 years ago 62 replies

I have a switching application where a single bipolar transistor might be used. The AC input is about 300mV and the transistor needs about 700...

I have a switching application where a single bipolar transistor might be used. The AC input is about 300mV and the transistor needs about 700 mV to switch on. My idea is to construct a voltage divider using a diode which will produce about a 600mV drop across the diode and a voltage divider of 2 equal resistors to set the transistor base voltage at about 300 mV so the transistor will sw...


Looking for Data on Toshiba S5977 Diode power Module 4B GTR IGBT

Started by amdx in sci.electronics.design2 years ago 3 replies

I have a few of these and don't know exactly what they are and can't find a schematic of the internals or a data sheet. I've tried about 5...

I have a few of these and don't know exactly what they are and can't find a schematic of the internals or a data sheet. I've tried about 5 different search engines and different search terms without success. Anyone with better google foo than mine? These first 5 pictures show the part. > https://duckduckgo.com/?q=Toshiba+S5977+Diode+-satellite&t=ffnt&atb=v229-2&iax=images&ia=images


LT Spice diode C-V graph

Started by John Larkin in sci.electronics.design8 years ago 55 replies

What's an easy way to plot the C-V curve of a back-biased diode? Maybe a constant-current ramp, then a differentiator, and a little math...

What's an easy way to plot the C-V curve of a back-biased diode? Maybe a constant-current ramp, then a differentiator, and a little math block? Or, flip that over, constant voltage ramp and current sensor, less math. Low level AC voltage on top of a DC sweep, and some sort of AC current detector? (Fake Boonton) -- John Larkin Highland Technology, Inc jlarkin a...


faston connector spacing

Started by Winfield Hill in sci.electronics.design3 years ago 2 replies

Our RIS-796 250-amp LED current pulser has been operated up to 1100A by Rob Legg, and is well suited to make shaped current pulses up to...

Our RIS-796 250-amp LED current pulser has been operated up to 1100A by Rob Legg, and is well suited to make shaped current pulses up to 750 amps. E.g., "8.3ms single half sine-wave" for "Peak forward surge current" diode testing. Manufacturers like to make rating plots for 1 to 100 cycles, etc. For example, a SMD or SMC diode I'm considering is rated at 350A for one cycle, dr...


Small Schottky diodes at very high currents

Started by Winfield Hill in sci.electronics.design3 years ago 9 replies

We're making fast 200 to 350-amp LED pulses with RIS-796 circuits (discussed here multiple times), and at switch-off the resulting inductive...

We're making fast 200 to 350-amp LED pulses with RIS-796 circuits (discussed here multiple times), and at switch-off the resulting inductive flyback could ruin the LED. We clamp the flyback current with a Schottky diode. But its 200 to 350A peak current can be far above normally accepted diode operation levels. This documents some measurements I've taken, Rob Legg is taking more....


Power supply for Buck dc-dc

Started by Anonymous in sci.electronics.design10 years ago 19 replies

Hi, Please, could I use a half-bridge diode circuit to power this buck power supply...

Hi, Please, could I use a half-bridge diode circuit to power this buck power supply ? http://www.ebay.com/itm/ZXY6005-DC-DC-60V-voltage-and-current-constant-power-supply-module-/1906 49685203?pt=LH_DefaultDomain_0&hash=item2c639b54d3 This power supply accepts 62VDC input, so if I use one rectifier diode to rectify 120Vac home's power (decay to ~ 54Vdc), it will work ? 120Vac -> 1 rectif


USB to TP4056 charger - why is the diode there?

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

This is the relevant part of the schematic of an 18650 battery charger and boost converter (to 5V)...

This is the relevant part of the schematic of an 18650 battery charger and boost converter (to 5V) module: https://i.postimg.cc/Tw7X35Fq/USB-to-TP4056.jpg And here's the module: https://www.aliexpress.com/item/32870411748.html Coming from the USB power pin, there's a series Schottky diode and a very low value resistor. The resistor is found in the TP4056 datasheet typical applic...


Low Barrier Height Diodes

Started by Cursitor Doom in sci.electronics.design2 years ago 4 replies

Gentlemen, Can someone suggest a commonly available diode with a very low Vf capable of passing up to 1A continuously and with a reverse...

Gentlemen, Can someone suggest a commonly available diode with a very low Vf capable of passing up to 1A continuously and with a reverse breakdown of at least 24V? A Vf of 0.2V or less would be nice. Thanks.


varicaps?

Started by John Larkin in sci.electronics.design3 years ago 126 replies

They seem to be getting obsolete. Maybe I can cheat and use a regular pn diode. -- John Larkin Highland Technology,...

They seem to be getting obsolete. Maybe I can cheat and use a regular pn diode. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com


Rectifying RF

Started by Cursitor Doom in sci.electronics.design3 years ago 20 replies

Gentlemen, Say I want to rectify RF of up to 30Mhz so I can read its amplitude with a milivoltmeter, what sort of diode would be suitable?...

Gentlemen, Say I want to rectify RF of up to 30Mhz so I can read its amplitude with a milivoltmeter, what sort of diode would be suitable? I'm guessing I can't use a common 1Nxxxs series jellybean as I would for 50 or 60Hz; I'd need a fast recovery type, yes? And what if the RF in question was only a hundred millivolts or so? That's not enough to overcome the barrier height potential of a ...


What diode to use for a primary side rcd clamp?

Started by Johann Klammer in sci.electronics.design2 months ago 3 replies

Specifically the LNK616 flyback regulator. They have 1N4007 in their dataheets/appnotes. But the 1N4007s trrs are all over the place. Often...

Specifically the LNK616 flyback regulator. They have 1N4007 in their dataheets/appnotes. But the 1N4007s trrs are all over the place. Often around 1us. The regulator has a minimum on-time of 700ns, and really does not like surge currents. What are better specced alternatives?


Unconnected part LTSpice seems to need (weird ...)

Started by Joerg in sci.electronics.design11 years ago 81 replies

Folks, This is close to voodoo but repeatable. Unfortunately I can't disclose the schematic since it is for a client. Just wondering , anyone...

Folks, This is close to voodoo but repeatable. Unfortunately I can't disclose the schematic since it is for a client. Just wondering , anyone had this before? At the far end of a TX line I used to have a diode connected across because a previous version of a chip would have such a substrat path. Nice waveforms, fast sims. Everything as expected and peachy. Now the new iteration of the c...


Simple pulse stretcher

Started by George Herold in sci.electronics.design10 years ago 94 replies

Hi guys, I need a little digital pulse stretcher. I've got pulses that are 5ns to 25ns in width, and I'd like to bump them all up to all be at...

Hi guys, I need a little digital pulse stretcher. I've got pulses that are 5ns to 25ns in width, and I'd like to bump them all up to all be at least 10ns. I've got a few spare 74HC14 inverters. I was thinking of just feeding one through a diode followed by an R/C to ground. Any other ways? There might be an extra AND gate too. (not my circuit so I'm not quite sure.) Thanks George...


Negative resistance with BJTs

Started by Anonymous in sci.electronics.design4 years ago 54 replies

a four layer diode, consisting of alternate p, n layers acts as a negative resistance, and can be realized in practice with a pair of NPN and...

a four layer diode, consisting of alternate p, n layers acts as a negative resistance, and can be realized in practice with a pair of NPN and PNP transistors, connected in specific ways. Now, is it possible to achive this a series connection of two discrete diodes ? I was just thinking about it.


The tunnel diode is back, as TeraHertz oscillator

Started by Jan Panteltje in sci.electronics.design11 months ago 11 replies

Terahertz radiation source: Compact and simple: https://www.sciencedaily.com/releases/2022/01/220111112018.htm paper: ...

Terahertz radiation source: Compact and simple: https://www.sciencedaily.com/releases/2022/01/220111112018.htm paper: https://aip.scitation.org/doi/10.1063/5.0068114 Interesting on chip construction


TVS diode in LT spice

Started by John Larkin in sci.electronics.design4 weeks ago 4 replies

.model SMCJ33A D(Ron=.4 Roff=8Meg Vfwd=.7 epsilon=100m Vrev=38.65 Vpk=33 revepsilon=4 mfg=Littlefuse type=TVS) That's in the standard library....

.model SMCJ33A D(Ron=.4 Roff=8Meg Vfwd=.7 epsilon=100m Vrev=38.65 Vpk=33 revepsilon=4 mfg=Littlefuse type=TVS) That's in the standard library. It behaves like a symmetric zener. Why? Does "type" do that? There are unipolar TVS diodes, too.


LTspice Zener Models

Started by Rick C in sci.electronics.design3 years ago

I'm looking to model a circuit with a zener diode in it and the exact part doesn't seem to have a simulation model. Looking at the 11 choices in...

I'm looking to model a circuit with a zener diode in it and the exact part doesn't seem to have a simulation model. Looking at the 11 choices in LTspice I see a variety of parameters. The one that I'd probably want to match the most closely is the source resistance, Rs. This seems to be a very difficult number to pin down. The part in question is CZRU52C6V2 by Comchip. They l


Turbo Royer/Baxandall in boost configuration

Started by bitrex in sci.electronics.design1 year ago 62 replies

Is it possible to take your standard Baxandall and tap the capacitor, take an aux winding off the secondary and feed a somewhat higher DC...

Is it possible to take your standard Baxandall and tap the capacitor, take an aux winding off the secondary and feed a somewhat higher DC voltage to the cap (through the usual two-diode supply handoff arrangement), and use it to feed the gate drive to the transistors as well, which would be clocked rather than self-oscillating. The goal would be to have a quiet step-up converter that co...