"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...
I know you can get custom PCBs in pretty large form factors, but I had no idea they were making wafers that big, too! ;-)
Tim
16 Pixels x RGB is a typical chip, then arrays of these on the PCB. ...Jim Thompson
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I love to cook with wine. Sometimes I even put it in the food.
Can you offer a few part numbers?
Not sure why you limit this to pipelined SAR. Subranging also has to do multiple steps which can be pipelined or not. But more importantly, there can be some "issues" at the edges of a range which require correction. In face, subranging flash converters are also referred to as pipelined... a rose by any other name...
-- Rick
We used to use buckets of those ~30 years ago.
It was a cool application, essentially an all-analog "arb generator".
We cascaded several LM3914s. The outputs each drove a slider potentiometer. These were summed such that you setup the waveform on the slider array and it output the shape you set.
A clever bit was to inject a triangle wave dither; this interpolated between the set points so there were no steps. This also dithered the LED mounted above each slider so there was a smoothly moving blob of light rather than a stepping one, indicating the "current" position in the signal. (It was a slow signal for hydraulic positioning).
-- John Devereux
Fun. The Exact company used to make an analogue arb with about 30 pots on the front panel and a counter + mux to switch between them.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
I once saw a really fast arb that used the reflections on a tapered transmission line to define the waveform. The line was a machined brass plate clamped over a delectric, over a ground plane. Some cool software read in the desired waveform and programmed an n/c mill to cut the brass.
I think that was used on the Nova laser, the prototype for NIF.
-- John Larkin Highland Technology, Inc picosecond timing laser drivers and controllers jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Job security for somebody, for sure. I've made fast pulse networks using an SD-24 TDR head and open or shorted coax stubs. That transmission line stuff really works.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net
Pretty much everything 10(+) bit-ish and high-speed from Analog devices,
like the AD9257 or whatever else that starts with AD92... or AD96...
Dimitrij
The LTC2242 family goes from 125 MHz/10 bits up to the one we use,
250/12. Pipeline delay is 5 clocks.Here's one on a board, 12 bits of LVDS into an Altera FPGA, at 250 MHz.
We are seeing less than 1 LSB of RMS noise. That was shocking, especially considering all the switching supplies an inch or so away.
-- John Larkin Highland Technology, Inc picosecond timing laser drivers and controllers jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Six of one, a half-dozen of the other... :)
The LT part John mentioned must be such a mixture, with a pipeline delay less than NOB. Of course, it could always be 100% flash with serdes pipelines, but... why?
Subranging, yes, that's a good word for it.
Tim
-- Seven Transistor Labs Electrical Engineering Consultation Website: http://seventransistorlabs.com
This is not a pipelined SAR converter. From page 18 of the data sheet...
"Each stage of the pipeline, excluding the last, consists of a low resolution flash ADC connected to a switched-capacitor DAC and an interstage residue amplifier"
Pipelined - yes. SAR - no. This is just an extension of the subranging flash converter I was talking about.
-- Rick
I'm not sure what you are saying. They are clearly pipelined, but flash and not SAR.
-- Rick
Yeah, that's what I mean.
At a glance, here's an example like I was thinking of earlier (and as Dimitrij mentioned):
Tim
-- Seven Transistor Labs Electrical Engineering Consultation Website: http://seventransistorlabs.com
I'm not following what you are saying. This is another pipelined flash part, not SAR. It has the exact same text on page 25 saying each pipeline stage has a low resolution flash converter. Maybe they are not describing it well and these are SAR converters. I don't know why it would take 16 clocks for a subranging converter. But I do know they need to do corrections so that may take some of the extra clock cycles.
-- Rick
Seems like the only difference is how maby bits get added per pipeline stage. Back when it was one bit (SAR), N/2 bits (half-flash), or N bits (flash), the distinction was cleared than it is now.
Cheers
Phil Hobbs
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