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 | |
| Voice480)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.

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

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 | |
| Voice480)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.

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

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

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 | |
| Voice480)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.

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

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 | |
| Voice480)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.

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

"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

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

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

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

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

"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

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

"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

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

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

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

"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

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

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

"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

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