Faster than 2n7002

Nice- worth having some on hand just for the low voltage drive. 5.3 ohms Rds(on) with 1.8V drive.

Thanks!

Yes, very nice. Only $0.18 at Digi-Key. But what is that package, damn it's small!

That series gate resistor may trash the speed. The data sheet suggests that it does.

I've made a pulser that uses two 2N7002s in parallel to drive a 1:1 transmission line transformer. It will make a 50 volt pulse into 50 ohms with rise/fall times below 2 ns. You've just got to drive the gates hard.

I was thinking it's faster for nano-power one-cell stuff, where picofarads matter. I realize my subject line wasn't specific enough.

I found the FET looking for a realllyyyy low-voltage part for low-voltage fun, but, after our thread on the 2n7002, I thought it was also nifty to see built-in ESD protection.

I had a customer kill some BSS138s on a board's internal nodes last year, mishandling. ZAP! Who expects electro-static discharge there? But, the boards died, and a protected FET would not have failed.

Nice trick.

Cheers, James Arthur

Yes, Rohm does that a lot. Fortunately, with SMD it's just a footprint.

I like the idea of .8v logic, oscillators, (noisy) amplifiers, etc.

Cheers, James Arthur

"Fast" begins at 1 ns. "Really fast" at 100 ps.

Having grown up in New Orleans, and living in San Francisco, I tend to forget that some places have ESD.

Most mosfets will switch a lot faster than their data sheets imply.

Sure. Here's a beefier, 50V part, ESD-protected, Vth

Nice to see some options that trade off higher Rds(on) for input capacitance, but still have modern low Vgs(th) in the 1V range.

Last time I needed one, all I could find readily was the little guys that can switch amperes at low voltage but have high gate capacitance.

--sp

Also, isn't the resistor in the wrong place? Like external gate pin, resistor, zener? That way there is less chance of frapping the protecton zener.

That's a fairly standard size - still within range of Press-n-Peel Blue and a cheap laser printer for hobbyists.

After years of building bulky, hot, expensive, fragile boards from Radio Shack and Electronics Plus, I like the idea of fitting a 50W switching power supply onto a 1" square board.

On a sunny day (Wed, 15 Apr 2015 14:58:10 -0700) it happened John Larkin wrote in :

Walk a mile in my shoes....

I draw 1 inch sparks in the supermarket, to the point that it hurts. Did not crash the cash register yet.

I once designed the data network for a large supermarket chain, zeners everywhere.

The real reason for those ESD-safe wooden shoes?

Best regards, Spehro Pefhany

On a sunny day (Thu, 16 Apr 2015 08:25:59 -0400) it happened Spehro Pefhany wrote in :

I dunno, something the soles are made of..

He's Dutch?

Yea, that was the trend for MOSFETs anyways, but the newer devices have lower gate capacitances.

Cheers

I always thought that electronic assembly should be done by naked girls sitting in tubs of tepid water.

Yes. But the resistor itself might get vaporized or punched through by an ESD pulse. So, why have the resistor at all?

Nononononono. Girls in hot tubs are far more dangerous than mere lightning. Ask anyone, especially wives. ;)

Cheers

Phil Hobbs

The 2N7002 still looks good for a lot of uses.