fast ramp follies

Thanks, Fred! I should have thought to look in my PSpice libraries, found it in Philips_RF.lib... minor differences in parasitics...

• SOT23 parasitic model Lb 4 5 .4n Le 7 8 .83n L1 2 4 .35n L2 1 6 .17n L3 3 8 .35n Ccb 4 6 71f Cbe 4 8 71f ...Jim Thompson

Bill Sloman a écrit :

.....

For you posting this I had a closer look and it happens that I also have the NXP model in my database, so a sanity check simulation was done.

Apart from the slope difference coming from a huge difference in Q3 VBE (110 to 115mV) the transient responses are *very* similar, despite the different ft (5.8G for the Q3 NXP against 4.8G for the infineon model) which is a good sign :-)

BTW, at more than 800mV VBE for the NXP model I tend to not trust it in that respect...

Yep, and in the die parameters too. Not surprising, but the bias point discrepancies make this NXP model suspicious.

First the 'measured' beta at 10mA is way in the low range for NXP at 25 (for 20 min/50 typ in NXP datasheet). So much for centering...

Also the FTs are 4.8 for Infineon against 5.8 for NXP... Not far, but the datasheets say 5GHz at 15mA/ and 10V VCE bias where it's used here with only 1.8V

I guess I trust the Infineon model more...

I would. For another project I just downloaded the Infineon CoolMOS libraries. I guess I should go back and get the BJT's as well. ...Jim Thompson

You delude yourself, old man.

I did Ib correction with one resistor and half of a dual opamp. Microwave PNPs have insane betas, like 20. You propose to ignore base current over temperature? Yeah, right, you have a better way to do this, but you won't reveal it. Pitiful bluff.

I wouldn't Spice my fast current source designs. The fast stuff would be inaccurate because the part models aren't good enough. The slow loops, like the Ib correction, are way too simple to need Spicing.

EUV light source controller. EUV energy/waveform digitizer. Particle discriminator. Four different laser drivers. LVDT/synchro simulator. USB picosecond pulse generator. Ethernet interfaced picosecond-resolution 5-channel time stamper. NMR gradient driver and temperature controller combo. Bunch of fiberoptic stuff. A couple of fast high-voltage pulsers.

The thing I like about designing this stuff is that I release the drawings to production and they crank out copies, and revenue, for a decade or so afterwards. I never sell IP or engineering.

Crap! I have ignition systems (still) running in cars where the control device had a nominal beta of THREE with IB correction. Read Frederiksen's tome... I invented such schemes.

You don't have any to sell. I have 18 patents. How many do you have? ...Jim Thompson

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Of course I have IP. But I use it in my own products and don't sell it for a one-time consulting fee. In a few cases, I license it, which just means that someone else does the manufacturing to make my ongoing revenue stream. But they don't own it.

I have 18 patents. How many do you have?

One, but I have rights to use it. How many of your 18 are assigned to someone else?

How much of the IP in your active patents can you sell? Patents are a suckers's game if they are assigned to someone else. You get to brag, but they get the money.

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Patents aren't any kind of sucker's game, but it doesn't make sense to own one if you haven't got the resources to defend it in court, which can take years and cost millions of dollars.

Those of us who worked for other people rather liked being named as the inventor on a patent. It looks good on your CV, and doesn't cost you anything. Admittedly some employers are more enthusiastic about patents than others. Two of my three patents come from my three years at EMI Central Research, and the other one from my nine years with Cambridge Instruments (in Cambridge UK) where I was no less productive but where the company didn't have a full-time patent department.

-- Bill Sloman, Nijmegen

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Don't forget the ICL7135 ... this datasheet was updated in 2007.

I lusted for that part in a design ages ago, but it was much too expensive, ~$15 IIRC (roughly $40 today). I rolled my own instead:

I got a bucket of galvanically isolated 4-1/2 digit ICL7135 isolated LED digital panel meters at a flea market not too long ago, for less than the 1pc chip price back in the day.

-- Cheers, James Arthur

That would have been a nice part a few years back, ~15 bits for $3. DPMs are about the only reasonable use for one nowadays, of course.

Cheers

Phil Hobbs

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I get royalties for 5 of them... keeps me in wine ;-) ...Jim Thompson

Patent number?

All, but I receive royalties from five. ...Jim Thompson

Funny. Any idea where ECAP, PCAP and Sceptre fit in? Not a mention in the 'pedia. Little better on the web.

RL

Maybe 7,019,307?

What the heck is wrong with a NIC??? Your slew rate is well within the reach of modern high speed amps:

Please view in a fixed-width font such as Courier.

. . . . .------[R]--+-------[R]---. . | | | . --- | |\ | . /// '--|-\ | . | \ | . | >------+--->

. | / | . .--|+/ | . | |/ | . | | . | | . Vref>----[R]--+-------[R]---' . | . ------+ . | | . |- === . sw>--| | . |--------+ . --- . /// . . .

So, the 'post hole digger' owns a 'Post Hole Digger'.

Sceptre was somewhat similar to spice but oriented about transient radiation effects. My dad was using that while i was a teen also. Plus = i must mention that Wikipedia is not always right.

If you look it up spice 2 was released in 1972, spice 1 previously known as CANCER was much earlier (mid 1960s).

?-)

Ur mum gay lol

That link didn't work for me.

Those 5GHz wide-band transistors do seem to need a base-stopper.Back in 198

I had the idea that getting the base impedance right some other way might s top them oscillating, but never got anywhere with testing the idea - other problems kept on getting in the way.