Favorite reverse bias protection for battery circuits

Googling on MC1253 yields nada... You typo'd... it's MCP1253 :-)

Just put an NPN in the ground feed. ...Jim Thompson

Cowards: No V/I characteristics around zero.

Hides a potential can of worms.

..... the normally-off synchronous rectifier has been a bee in my bonnet for a long time.

RL

he

Joerg, you big spender! Use an n-FET--they're better and cheaper--in the ground lead.

-- Cheers, James Arthur

Yup, that's what I'd do in this case :-)

Where do you get a discrete NMOSFET that will be thoroughly on at 1.8V VGS?

The Micrel part _may_ work. ...Jim Thompson

Here's one:

Does n-channel still offer a cost advantage over p-channel for very low voltage devices?

Here's a p-channel device with 113m ohm at 1.2V Vgs.

Apparently a SC-70 can dissipate 19W if you can hold the case to

Plenty of others. If it has to be cheap (and somehow it always has to be...), here's an example at around 15 cents, Rdson guaranteed down to 1.5V:

You need to get out into the world of discretes some more :-)

I don't think so...

It appears that the N-channel part is made on an P-substrate and vice-versa.

Nice devices! ...Jim Thompson

Nope! I avoid markets that are priced like popcorn.

Except for my own G-jobs :-) ...Jim Thompson

Oh, it's not always that way. Roughly half of my designs aren't required to be rock-bottom in BOM cost. Although I can't help it, the calculator in my head is always running. Sometimes clients are surprised when they see the (working) circuit. "You mean, that's it?"

I get that all the time. I really enjoy finding clever solutions to difficult problems. If I ever lose that capability I'll simply self-dispatch :-) ...Jim Thompson

That's squarely against my religious beliefs. Life doesn't end with Alzheimers and the like. In fact, our new canine addition (former guide dog trainee, hopefully passes therapy dog cert after Easter) will have one such case very soon. And already has served in that area.

Young buck say to old buck: N-channel mostly less bucks for same bang :-)

I don't have much in examples anymore because the notes about p-channel candidates where used to kindle the wood stove. But it happened time and again when I thought about push-pull drivers and two n-channels plus bootstrap was the better deal (financially).

I only believe in myself, so I have no such problem :-) ...Jim Thompson

That was true in the past. Now-a-days I see no rationale for a price difference except for "what the market will bear" :-) ...Jim Thompson

There really is a penalty. Yeah, initially the difference may seem tiny or zilch but if you want a P-channel with the same performance as the N-channel and not just 70%, very different thing.

Then you'll have a (huge) problem after you die ;-)

I promise to not be "greasy" :-) ...Jim Thompson

has to=20

down to 1.5V:

required=20

calculator=20

they=20

to

guide=20

have=20

So there is going to be past passing party where there will be JT chops = and=20 sausages and handouts of smoked JT?