Re: What's the hi-side current sense chip du jour?

miso@xxxxxxxxx wrote:
On Jun 2, 9:05 am, John Larkin
<jjlar...@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
On Tue, 2 Jun 2009 00:12:32 -0700 (PDT), "m...@xxxxxxxxx"



<m...@xxxxxxxxx> wrote:
On Jun 1, 6:23 pm, MooseFET <kensm...@xxxxxxxxx> wrote:
On May 31, 1:00 pm, John Larkin<jjlar...@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
On Sun, 31 May 2009 12:22:30 -0700 (PDT), MooseFET
[... bugs in chips...]
(2) Early LT1028 datasheets cut off the noise graph before the ugly
rise to a peak that happens near 300KHz.
That's downright dishonest.
I think it was more like a blunder than anything. They overlooked
what happens when the input pair runs out of steam. I am fair certain
that if you look at the current data***, it is clearly shown.
One Hittite switch data *** states boldly that it works from DC to 4
GHz. Turns out their in-house definition of DC is 100 MHz.
I sometimes deal with AC at 0.001 Hz or lower. I guess I should stay
away from that one.
[1]
THS3062 is great, as long as you don't ask it to amplify sine waves
anywhere near a third of its swing or slew rate specs. If you do, it
latches up and gets hot enough to put a hole in your finger. A little
time spent phoning tech support (six weeks in our case) will verify
that this is maybe true, in not so many words, and that it's really
your fault.
Another part not to use. I drive op-amps up to their slew rate limits
fairly often
LM35 is a very sensitive latching pulse detector, as well as a
temperature sensor and general-purpose oscillator.
Mini-Circuits MMIC data sheets should state that "fab houses and gross
performance are subject to unannounced, random, radical change" and
"we don't actually know much about these parts." Optek lasers, ditto.
Don't even get me started on voltage regulator capacitive-load
stability.
That is LDOs. References often has words like "with a xxxuF load" in
the data*** that you need to look for carefully. Some references
hate large capacitors and others love them.
[1] Lately LTC uses the term "LF" instead of the often-dishonest "DC"
I never did an amp with 3 gain stages, but I can see the 1028 getting
funky at the high end. Still an impressive bit of silicon after all
these years. It's been bettered, but not by great margins.
Maxim introduced a MAX1028, then pulled it. There must be a story.

John

The designer of Maxim's 1028 knew the engineer at LT that did the
1028. [Hey, this is the way of the valley.] I don't know if there was
any bad blood after the 2nd source came out, and I never heard of a
lawsuit regarding the product.

I believe the Maxim 1028 was sold for a while because a friend in Hong
Kong found them available for sale. Of course, the hifi guys there
wanted the real thing (LTs part). I suspect if it is no longer
available, it was a fab issue. One of the outside fabs was eliminated
and lots of old chips could not be produced. In fact, one was a nice
high side current sense chip, which brings us back to the original
question.

My recollection is the first pass had a temperature issue, but those
parts don't go on the market. What was sold should have met the LT
spec.

I think bettering the 1028 means making some other spec worse. For
instance, larger input devices means more capacitance, higher
operating current means more leakage, etc.


Blows my mind, they brought out an ADC under the same name:
http://datasheets.maxim-ic.com/en/ds/MAX1026-MAX1030.pdf

I mean, even with their mind-boggling unobtanium rate, can they not properly retire a jersey like sports teams do?

--
Regards, Joerg

http://www.analogconsultants.com/

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