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Thermometer Code Chip
I'm looking for a chip that outputs a Thermometer Code.
I vaguely remember such a device. Is there one still made? ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
Thermometer Code Chip
On Fri, 03 Apr 2015 09:57:15 -0700, Jim Thompson
wrote: I'm looking for a chip that outputs a Thermometer Code. I vaguely remember such a device. Is there one still made? ...Jim Thompson LM3914 -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com |
Thermometer Code Chip
On Fri, 03 Apr 2015 10:31:16 -0700, John Larkin
wrote: On Fri, 03 Apr 2015 09:57:15 -0700, Jim Thompson wrote: I'm looking for a chip that outputs a Thermometer Code. I vaguely remember such a device. Is there one still made? ...Jim Thompson LM3914 Thank you! Google couldn't get me there :-( ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
Thermometer Code Chip
On Fri, 3 Apr 2015, John Larkin wrote:
On Fri, 03 Apr 2015 09:57:15 -0700, Jim Thompson wrote: I'm looking for a chip that outputs a Thermometer Code. I vaguely remember such a device. Is there one still made? ...Jim Thompson LM3914 No, that's the dot/bar display driver, takes in analog voltage and displays on a set of LEDs. If we're talking about a TO-92 packaged device that outputs a DC voltage depending on temperature, it was three numbers after the "LM" and close to the combination of numbers in "3914" but I cant' remember the exact number. Michael |
Thermometer Code Chip
On 3.4.15 20:56, Michael Black wrote:
On Fri, 3 Apr 2015, John Larkin wrote: On Fri, 03 Apr 2015 09:57:15 -0700, Jim Thompson wrote: I'm looking for a chip that outputs a Thermometer Code. I vaguely remember such a device. Is there one still made? ...Jim Thompson LM3914 No, that's the dot/bar display driver, takes in analog voltage and displays on a set of LEDs. If we're talking about a TO-92 packaged device that outputs a DC voltage depending on temperature, it was three numbers after the "LM" and close to the combination of numbers in "3914" but I cant' remember the exact number. Michael TI's LMT70, LMT84 to LMT90? -- -TV |
Thermometer Code Chip
On Fri, 03 Apr 2015 21:18:46 +0300, Tauno Voipio
wrote: On 3.4.15 20:56, Michael Black wrote: On Fri, 3 Apr 2015, John Larkin wrote: On Fri, 03 Apr 2015 09:57:15 -0700, Jim Thompson wrote: I'm looking for a chip that outputs a Thermometer Code. I vaguely remember such a device. Is there one still made? ...Jim Thompson LM3914 No, that's the dot/bar display driver, takes in analog voltage and displays on a set of LEDs. If we're talking about a TO-92 packaged device that outputs a DC voltage depending on temperature, it was three numbers after the "LM" and close to the combination of numbers in "3914" but I cant' remember the exact number. Michael TI's LMT70, LMT84 to LMT90? Those are temperature sensors, _not_ thermometer code. See LM94022 on the Device Models & Subcircuits page of my website. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
Thermometer Code Chip
On Fri, 3 Apr 2015 13:56:11 -0400, Michael Black wrote:
On Fri, 3 Apr 2015, John Larkin wrote: On Fri, 03 Apr 2015 09:57:15 -0700, Jim Thompson wrote: I'm looking for a chip that outputs a Thermometer Code. I vaguely remember such a device. Is there one still made? ...Jim Thompson LM3914 No, that's the dot/bar display driver, takes in analog voltage and displays on a set of LEDs. Which decode pattern is often referred to as a "thermometer code." Apparently, that's what Jim wanted. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com |
Thermometer Code Chip
On Fri, 03 Apr 2015 11:33:46 -0700, John Larkin
wrote: On Fri, 3 Apr 2015 13:56:11 -0400, Michael Black wrote: On Fri, 3 Apr 2015, John Larkin wrote: On Fri, 03 Apr 2015 09:57:15 -0700, Jim Thompson wrote: I'm looking for a chip that outputs a Thermometer Code. I vaguely remember such a device. Is there one still made? ...Jim Thompson LM3914 No, that's the dot/bar display driver, takes in analog voltage and displays on a set of LEDs. Which decode pattern is often referred to as a "thermometer code." Apparently, that's what Jim wanted. Yes. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
Thermometer Code Chip
On Fri, 03 Apr 2015 11:35:04 -0700, Jim Thompson
wrote: On Fri, 03 Apr 2015 11:33:46 -0700, John Larkin wrote: On Fri, 3 Apr 2015 13:56:11 -0400, Michael Black wrote: On Fri, 3 Apr 2015, John Larkin wrote: On Fri, 03 Apr 2015 09:57:15 -0700, Jim Thompson wrote: I'm looking for a chip that outputs a Thermometer Code. I vaguely remember such a device. Is there one still made? ...Jim Thompson LM3914 No, that's the dot/bar display driver, takes in analog voltage and displays on a set of LEDs. Which decode pattern is often referred to as a "thermometer code." Apparently, that's what Jim wanted. Yes. ...Jim Thompson More detail for the lurkers: https://en.wikipedia.org/wiki/Unary_coding -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com |
Thermometer Code Chip
"John Larkin" wrote in message
... More detail for the lurkers: https://en.wikipedia.org/wiki/Unary_coding It's a 10 bit unary ADC, and can be used as such. I've done it before. :) Tim -- Seven Transistor Labs Electrical Engineering Consultation Website: http://seventransistorlabs.com |
Thermometer Code Chip
On Fri, 3 Apr 2015 14:15:52 -0500, "Tim Williams"
wrote: "John Larkin" wrote in message .. . More detail for the lurkers: https://en.wikipedia.org/wiki/Unary_coding It's a 10 bit unary ADC, and can be used as such. I've done it before. :) Tim Classic flash ADCs used 2^n comparators and a resistor string in the front end. The resulting (say, 256 bit) thermomometer code was then mapped into binary. I think somebody did that at 10 bits, 1024 comparators. Nowadays people tend to do cleverer things. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com |
Thermometer Code Chip
On 4/3/2015 12:57 PM, Jim Thompson wrote:
I'm looking for a chip that outputs a Thermometer Code. I vaguely remember such a device. Is there one still made? They come in a wide variety of packages and range in cost from $0.50 to a couple of dollars in quantity. The number of outputs also varies widely, with both linear and analog ranges. What are you looking for specifically? -- Rick |
Thermometer Code Chip
On 4/3/2015 3:36 PM, rickman wrote:
On 4/3/2015 12:57 PM, Jim Thompson wrote: I'm looking for a chip that outputs a Thermometer Code. I vaguely remember such a device. Is there one still made? They come in a wide variety of packages and range in cost from $0.50 to a couple of dollars in quantity. The number of outputs also varies widely, with both linear and analog ranges. What are you looking for specifically? Opps, that should be linear and *log* ranges... -- Rick |
Thermometer Code Chip
On 4/3/2015 3:15 PM, Tim Williams wrote:
"John Larkin" wrote in message ... More detail for the lurkers: https://en.wikipedia.org/wiki/Unary_coding It's a 10 bit unary ADC, and can be used as such. I've done it before. :) Tim I sometimes use it to display the noise floor in laser-based instruments, along with some three-colour Avago LED bargraphs and a simple false alarm rate servo. (see http://electrooptical.net/patents/US05204631__.pdf ). Watching the lights flicker is a surprisingly sensitive test for subtle problems, such as the very beginnings of laser instability. You can see noise floor variations of a small fraction of a decibel, and correlate them with things like scan position. 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 |
Thermometer Code Chip
"John Larkin" wrote in message
... Classic flash ADCs used 2^n comparators and a resistor string in the front end. The resulting (say, 256 bit) thermomometer code was then mapped into binary. I think somebody did that at 10 bits, 1024 comparators. Nowadays people tend to do cleverer things. Are they still de rigeur for the bleedingest of edges in the Hittite and etc. catalogs? Pipelined SAR has certainly come a long way since the olden days. I've seen an oddly large number of DACs that claim to do this, even for 12 bits. Seems odd that they'd succeed in using that many resistors and MOS gates. Could well be that they're doing some R-2R action regardless, maybe even a bit of each (an R-2R chain is binary, but an R-R-..-2R-2R-.. network would work for any base; the classic resistor decade box being such a case, for N = 10). Tim -- Seven Transistor Labs Electrical Engineering Consultation Website: http://seventransistorlabs.com |
Thermometer Code Chip
On 4/3/2015 9:07 PM, Tim Williams wrote:
"John Larkin" wrote in message ... Classic flash ADCs used 2^n comparators and a resistor string in the front end. The resulting (say, 256 bit) thermomometer code was then mapped into binary. I think somebody did that at 10 bits, 1024 comparators. Nowadays people tend to do cleverer things. Are they still de rigeur for the bleedingest of edges in the Hittite and etc. catalogs? Pipelined SAR has certainly come a long way since the olden days. Flash converters are the only choice for anything above around 1-2 MSPS last time I looked hard. Maybe they are pushing towards 10 MSPS with SARS and SD converters. But for anything higher a flash converter is the only choice. That said, there are different forms of flash converters. Up to about 8-10 bits all that I have seen were single stage. But by the time you reach 10 bits the number of comparators becomes unwieldy. For high bit counts or for lower power they use subranging with a pair of lower bit count flash converters, one with low resolution for the upper bits and one with high resolution for the lower bits. Essentially this is a hybrid of the flash converter and an SAR. To deal with the imperfections in matching the two it is common to have an overlap in the number of bits used. These are are the bleeding edge devices providing flash like performance at up to 16 bit resolution. But for the highest sample rates the direct flash converter is your huckleberry. -- Rick |
Thermometer Code Chip
"rickman" wrote in message
... Flash converters are the only choice for anything above around 1-2 MSPS last time I looked hard. Maybe they are pushing towards 10 MSPS with SARS and SD converters. But for anything higher a flash converter is the only choice. When did you last look? Two decades ago? :) All the ones I've seen (within say 5 years) from about 20 to 500 Msps and 8+ bits are pipelined SAR. Usually with terrible INL for the higher bits versions, but that reflects their usage: AC circuits, radio (SDR), ultrasound, etc., where low DNL is priority. Often, they're also in a series, so you get like, 65-80-110 Msps and 10-12-14 bits. Likely they use the same configurable die for everything in that series, and burn some fuses during test to implement the highest spec the chip meets. They either state what they are (pipelined SAR), or it's apparent from the timing -- usually LVDS, SDR or DDR output, where a given analog sample takes N+1 or so clocks to fully propagate through the chip. The INL/DNL graphs (if provided) also look much like typical SAR graphs; though I'll admit I haven't seen a wide breadth of ADC types to compare to. A flash converter could get more data (perhaps more parallel LVDS lanes?), with less latency (maybe N/M + 1 cycles, where M is the ENOB of the flash stage), but those don't seem to be common, at least in the ranges I've looked at. They often talk about "proprietary compensation stages" or something to that effect, suggesting that simply churning out a number in the conventional method isn't as simple when you're doing it at *that* rate. Maybe this is something they were missing, and hence why flash was the only option, back in the day? They're also moving away even from 3.3V logic these days; the 1.8V parts are something like 1/4 to 1/8 the power for the same specs. And much, much faster at the top end. Tim -- Seven Transistor Labs Electrical Engineering Consultation Website: http://seventransistorlabs.com |
Thermometer Code Chip
On 4/4/2015 3:40 PM, Tim Williams wrote:
"rickman" wrote in message ... Flash converters are the only choice for anything above around 1-2 MSPS last time I looked hard. Maybe they are pushing towards 10 MSPS with SARS and SD converters. But for anything higher a flash converter is the only choice. When did you last look? Two decades ago? :) All the ones I've seen (within say 5 years) from about 20 to 500 Msps and 8+ bits are pipelined SAR. Usually with terrible INL for the higher bits versions, but that reflects their usage: AC circuits, radio (SDR), ultrasound, etc., where low DNL is priority. Often, they're also in a series, so you get like, 65-80-110 Msps and 10-12-14 bits. Likely they use the same configurable die for everything in that series, and burn some fuses during test to implement the highest spec the chip meets. Can you offer a few part numbers? They either state what they are (pipelined SAR), or it's apparent from the timing -- usually LVDS, SDR or DDR output, where a given analog sample takes N+1 or so clocks to fully propagate through the chip. The INL/DNL graphs (if provided) also look much like typical SAR graphs; though I'll admit I haven't seen a wide breadth of ADC types to compare to. A flash converter could get more data (perhaps more parallel LVDS lanes?), with less latency (maybe N/M + 1 cycles, where M is the ENOB of the flash stage), but those don't seem to be common, at least in the ranges I've looked at. They often talk about "proprietary compensation stages" or something to that effect, suggesting that simply churning out a number in the conventional method isn't as simple when you're doing it at *that* rate. Maybe this is something they were missing, and hence why flash was the only option, back in the day? 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 |
Thermometer Code Chip
On 10.04.2015 06:20, rickman wrote:
On 4/4/2015 3:40 PM, Tim Williams wrote: "rickman" wrote in message ... Flash converters are the only choice for anything above around 1-2 MSPS last time I looked hard. Maybe they are pushing towards 10 MSPS with SARS and SD converters. But for anything higher a flash converter is the only choice. When did you last look? Two decades ago? :) All the ones I've seen (within say 5 years) from about 20 to 500 Msps and 8+ bits are pipelined SAR. Usually with terrible INL for the higher bits versions, but that reflects their usage: AC circuits, radio (SDR), ultrasound, etc., where low DNL is priority. Often, they're also in a series, so you get like, 65-80-110 Msps and 10-12-14 bits. Likely they use the same configurable die for everything in that series, and burn some fuses during test to implement the highest spec the chip meets. Can you offer a few part numbers? 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 |
Thermometer Code Chip
On Sun, 12 Apr 2015 01:15:58 +0200, Dimitrij Klingbeil
wrote: On 10.04.2015 06:20, rickman wrote: On 4/4/2015 3:40 PM, Tim Williams wrote: "rickman" wrote in message ... Flash converters are the only choice for anything above around 1-2 MSPS last time I looked hard. Maybe they are pushing towards 10 MSPS with SARS and SD converters. But for anything higher a flash converter is the only choice. When did you last look? Two decades ago? :) All the ones I've seen (within say 5 years) from about 20 to 500 Msps and 8+ bits are pipelined SAR. Usually with terrible INL for the higher bits versions, but that reflects their usage: AC circuits, radio (SDR), ultrasound, etc., where low DNL is priority. Often, they're also in a series, so you get like, 65-80-110 Msps and 10-12-14 bits. Likely they use the same configurable die for everything in that series, and burn some fuses during test to implement the highest spec the chip meets. Can you offer a few part numbers? 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. https://dl.dropboxusercontent.com/u/.../ESM_rev_B.jpg 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 |
Thermometer Code Chip
"rickman" wrote in message
... They often talk about "proprietary compensation stages" or something to that effect, suggesting that simply churning out a number in the conventional method isn't as simple when you're doing it at *that* rate. Maybe this is something they were missing, and hence why flash was the only option, back in the day? 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... 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 |
Thermometer Code Chip
On 4/11/2015 7:15 PM, Dimitrij Klingbeil wrote:
On 10.04.2015 06:20, rickman wrote: On 4/4/2015 3:40 PM, Tim Williams wrote: "rickman" wrote in message ... Flash converters are the only choice for anything above around 1-2 MSPS last time I looked hard. Maybe they are pushing towards 10 MSPS with SARS and SD converters. But for anything higher a flash converter is the only choice. When did you last look? Two decades ago? :) All the ones I've seen (within say 5 years) from about 20 to 500 Msps and 8+ bits are pipelined SAR. Usually with terrible INL for the higher bits versions, but that reflects their usage: AC circuits, radio (SDR), ultrasound, etc., where low DNL is priority. Often, they're also in a series, so you get like, 65-80-110 Msps and 10-12-14 bits. Likely they use the same configurable die for everything in that series, and burn some fuses during test to implement the highest spec the chip meets. Can you offer a few part numbers? Pretty much everything 10(+) bit-ish and high-speed from Analog devices, like the AD9257 or whatever else that starts with AD92... or AD96... 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 |
Thermometer Code Chip
On 4/11/2015 8:40 PM, Tim Williams wrote:
"rickman" wrote in message ... They often talk about "proprietary compensation stages" or something to that effect, suggesting that simply churning out a number in the conventional method isn't as simple when you're doing it at *that* rate. Maybe this is something they were missing, and hence why flash was the only option, back in the day? 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... 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. I'm not sure what you are saying. They are clearly pipelined, but flash and not SAR. -- Rick |
Thermometer Code Chip
"rickman" wrote in message
... 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. I'm not sure what you are saying. They are clearly pipelined, but flash and not SAR. Yeah, that's what I mean. At a glance, here's an example like I was thinking of earlier (and as Dimitrij mentioned): http://www.analog.com/media/en/techn...ets/AD9628.pdf 12 bits, propagation delay 16 cycles. Tim -- Seven Transistor Labs Electrical Engineering Consultation Website: http://seventransistorlabs.com |
Thermometer Code Chip
On 4/12/2015 12:13 AM, Tim Williams wrote:
"rickman" wrote in message ... 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. I'm not sure what you are saying. They are clearly pipelined, but flash and not SAR. Yeah, that's what I mean. At a glance, here's an example like I was thinking of earlier (and as Dimitrij mentioned): http://www.analog.com/media/en/techn...ets/AD9628.pdf 12 bits, propagation delay 16 cycles. 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 |
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