I am searching for a microcontroller with a 12bit ADC which is specified up to 150 degrees. Automotive AVRs go up to 150 degrees, but not 12bit, so I'll have to look at other suppliers.
Is anyone aware of such a part somewhere? So far microchip comes closest, but only at 125 degrees.
Igor
I know honeywell make a microcontroller certified up to 225 Celcius, but it doesn't have an A/D.
Does the A/D have to be internal?
Internal has a strong preference. It's for a low cost application with limited space.
Automotive AVRs go up to 150 degrees, but not 12bit, so I'll have to look at other suppliers.
(though it may be a while before you could lay your hands on automotive rated ones)
Check Freescale that now has a new line of 'low cost uC' with 12bit ADC, or Analog Devices (the ARM microconverters go up to 12bits 1MSPS).
On the other hand, remember that AVR's can do oversampling, thus improve readings up to 12 bits, depending on what do you want to convert. Not all uC can do that, but AVR's certainly. Been there, done that ;)
TI MSP430 has models with 12-bit A/D, but I don't know if they have models in the automotive temperature range.
Lee
Automotive AVR with oversampling will work... iff signal sits still for 4 sample times....
Thinking 150C (302F) is not chilly, not wire-insulation-friendly, I noted that Atmel defines its Automotive chips, in PRELIM data sheets, as
Automotive (-40° to +125°C)
which is a much more balmy 257F
Fear not, I read that leaded solder melts at about 183C and lead-free solder melts about 217C
Electronic devices with operating temperatures beyond 125°C are not likely to be found
in 'typical' Consumer/Industrial/Military products.
Downhole transducers made by Quartzdyne are specified to 150°C for their surface mount
version and to 200°C in their hybrid version. Rather than using an ADC for measurements
they seem to utilize quartz transducers and frequency measurements.
http://www.quartzdyne.com/performance/circuitlife.htm
Hmm, try yoyodyne too? http://www.yoyodyne.com/
Stan
At Freescale you will find exactly what you need.
Michael.
Thanks for the pointers guys.
Allthough most manufacturers rate their automotive components at 125C in the datasheet, I know the fabs have processes for 150/160 which are used for automotive applications. I'm curious if the datasheets are conservative....
Thanks for the pointers guys.
Allthough most manufacturers rate their automotive components at 125C in the datasheet, I know the fabs have processes for 150/160 which are used for automotive applications. I'm curious if the datasheets are conservative....
The datasheets are conservative in the manner that if you run the device within their parameters, they guarantee that it *will* work. Outside of those parameters, it's certain that every chip will exceed them by some amount, but to what extent which individual chip will exceed them is entirely a gamble.
The jump from 125C to 150C is a very significant one, and unless you don't care if your product doesn't work, I wouldn't chance it.
Why not try some heat insulation techniques to see if you can bring down the temperature a little? Semiconductors last longer at normal temperatures.
Hey... a peltier and a good heatsink on the hot side? :D
I know, I know... I'm just having fun.
Well, I do care about a working product. But actually more about whether high temperature will deteriorate the components. It is allowed to gracefully shut down when temperatures get too high.
I was just curious to see if there are uC suppliers that dare to guarantee 150C.
It is not beyond the realm of standard fab processes, I have asics on my desk that have automotive ratings of 150C. According to the designer the real problems only start at 180 for bond wires and eeprom.
It is allowed to gracefully shut down when temperatures get too high.
I would like it to operate as long as possible. As junction temperatures are already higher than ambient, a 125 degree certified component won't get you much beyond 110 degrees ambient.
I'll go harass some suppliers to see what they have to say on their own temperature ratings.
