0-300V DC signal generator

" snipped-for-privacy@fonz.dk" wrote in news: snipped-for-privacy@g9g2000vbl.googlegroups.com:

And both internally contain a Dig-TO-AN convertor.

stack.

oscillator,

It does look like a nice one. I just noticed the RC self-timing and that its datasheet mentioned the 555, so naturally I had to tease Bill about it. ;)

Cheers

Phil Hobbs

snipped-for-privacy@g9g2000vbl.googlegroups.com:

technically yes, but .. one can't always replace the other so you better ask for the right thing

-Lasse

stack.

oscillator,

Well, there are a few obvious ways to make an RC oscillator. It's unfortunate that anything that does it one of those ways gets guilt-by-association from the 555.

is a

stack.

oscillator,

The IR data sheet mentioned the 555 (according to Phil). Not surprisingly the 555 timer uses a basic fundamental technique to make accurate R/C oscillators.

Can you show us the other "few obvious ways to make an RC oscillator"? ...Jim Thompson

Another way is drive the capacitor in phase and the resistor antiphase and use a single threshold

.----+-\/\/\-. | | | | === | | | | `-|>-+--|>o--+--

sometimes done with both buffers inverting and the cap and resistor swapped. eg 4060.

and a third way...

umm an avalanche oscillator? .----------- out | +V --/\/\/--+-/\/\/--|\|--.

None of the CMOS inverter oscillators are very accurate, or stable, due to the ESD diodes getting in the way of natural logarithmic timing.

A fix that works well is...

or on-chip where ESD isn't present...

Extraordinarily unstable. ...Jim Thompson

Of course with nasty voltage-dependent capacitors, the 555's ratiometric scheme loses a lot of its PSR as well.

Cheers

Phil Hobbs

Only because of the crappy capacitor. In any production environment I've always opted for COG/NPO.

In my chip designs I use the version shown in the second link quite a lot. The chip capacitors I use are MOM (metal-oxide-metal) which are quite stable, just a +/- 20% initial value spread. In critical applications, some kind of trim procedure is used, sometimes laser, sometimes an auto-trim procedure when the chip "boots" up. ...Jim Thompson

innews:kmlef7$eae$ snipped-for-privacy@tdi.cu.mi.it:

is

of

with

Umm no. A fully floating (within the supply rails) variable voltage ratio. At least that what one of the spec sheets i read said.

?-)