more whining

Rediscovering fundamental applications of Ohm's law in an IC-centric bit-head world...give it a few and these magazines will deal mostly with articles such as "Effective Communication of Requirements to Your Chinese Design House."

It was the 7X vBE use that was giving me heartburn.

...Jim Thompson

Let's turn this into a "design" question...

Say I have an LM339 comparator running on ±5V since I want to sense zero-crossings of a 4V P-P sine wave.

Furthermore assume that the power supplies are sloppy, ±10%

How do I, without a horrible TC or an inaccurate low output level, produce an output that swings from ZERO to the positive rail?

...Jim Thompson

"Joerg" schreef in bericht news:H_gng.123053$ snipped-for-privacy@newssvr21.news.prodigy.com...

LDO?

Why low Iq if you have a truck battery? The Iq of the entire truck or even the battery leakage is many times higher than 5uA?

I didn't even look at figure 2/3- but if buffering is what he needs then he should have cascaded the fig 1a neg input pulse circuit with the outputs of the neg comparator, and avoid using circuits he knows nothing about.

When I was designing alternator regulators (mid 1960's) I was allowed up to 5mA of continuous drain.

...Jim Thompson

Hello Jeff,

Some parts in those series were specifically made for the MSP430 and groomed for low Iq. I just wish they were not LDO. As to cheap, well, not really but if they become popular there should be a downward trend in price.

With TI parts it can pay off to negotiate with the distributor.

Hello Frank,

This had to run on a smaller battery. But even with large vehicles one has to look at the whole picture. There is a lot more that hangs on the battery. Fuel gauges, alarms, entry system receivers, clocks, temp sensing etc. It adds up so it is wise to minimize the consumption for each.

Maybe something like this, Rc/Re>2: View in a fixed-width font such as Courier.

. . . . +5V . | . [Rc] . | . | . .----+---> OUT . | | . | | . | |/ . '--| . |>

. | . | . |/ . 0V--| . |>

. +5V | . | [Re] . |\\ | . ----| >------' . |/ . | . -5V . .

Thanks, Jim. I guess it counts as a published article for his resume:)

Even Bob Pease is dragging his tail. The tickler went like this:

"Dear Bob: When looking at datasheets or application notes that have the schematics of an IC in them, I often see very strange components; transistors with two, three, or even four collectors or emitters, and a component that looks like a capacitor where one plate is a resistor."

Oh boy,sez I. Now we will see some terrific insights into ic design, maybe like his articles on thermal matching input differential stages.

Instead, he simply says the current splits equally, and if you want more info, go to Hans Camenzind's Web site. Maybe we should get him to read s.e.d. for ideas on topics to write about. There's enough mistakes and misconceptions in one day's postings to keep him busy for a year:)

Regards,

Mike Monett

Buffer with a 74AC04.

Regards,

Mike Monett

Fred, That's passable, though it'll produce a low of VSAT; but a simple re-wire will get you much closer to ZERO.

...Jim Thompson

Typical wrong answer from a digital "designer" ;-)

...Jim Thompson

Nah, I'm analog. You want rail-to-rail, that's digital:) Regards,

Mike Monett

He actually said, "... split into _about_ four equal parts."

In reality not very equal due to the severe Early Effect in lateral PNP's. And let one collector saturate and all hell breaks loose.

...Jim Thompson

Must be this then- clever: View in a fixed-width font such as Courier.

. . . . +5V . | . [Rc] . | . | . .----+---> OUT . | | . | | . | |/ . 0V--|--| . | |>

. | | . | | . | |/ . '--| . |>

. +5V | . | [Re] . |\\ | . ----| >------' . |/ . | . -5V . .

Rail-to-ground from a ±V device.

But draw me a picture of how you'd do it.

...Jim Thompson

See what I mean? This is the kind of stuff that's interesting and useful.

Now we can check if there's any way to saturate a shared collector and ambush any newbies:) Regards,

Mike Monett

Uh? That gives you Vout = -Vsat ;-) I want ZERO ±mV's.

...Jim Thompson