Any idea why this chip would be this expensive? - Page 1
Forum section: electronics / general

author: AlphZeta
author_rank: Regular Contributor
timestamp: March 25, 2013, 01:32:49 pm
content: I was developing some prototypes using LM95172 (http://www.ti.com/lit/ds/snosb33a/snosb33a.pdf), but then was told that it would be near $130 each from major supply chains such as mouser/digikey.Now I am a little perplexed as to why this particular chip is that expensive. While it is (AEC-Q100 Grade 0) qualified and has a 16-bit ADC, but it's accuracy isn't that that great (up to 3.5 degree plus minus). It seems to me that there must be some other reasons that I missed?

author: jpb
author_rank: Super Contributor
timestamp: March 25, 2013, 01:44:32 pm
content: I have no specific information but I presume it comes down to size of market.A brief look at the data sheet seems to indicate that it is aimed at the car market which I'd have thought could be very large, but perhaps they've not managed to sell it to any large manufacturers so are trying to recoup their R&D costs over a much smaller base.Price may not be directly related to specs, look at DRAM chips - DDR2 chips are more expensive than DDR3 I think simply because the mass market is now DDR3.

author: AlphZeta
author_rank: Regular Contributor
timestamp: March 25, 2013, 01:51:30 pm
content: If it is manufactured for a niche market I could understand it being expensive, but for the automotive industry? I would have thought that they would make it cheaper so that car manufactures would want to use it in their cars...

author: rsjsouza
author_rank: Super Contributor
timestamp: March 25, 2013, 02:12:59 pm
content: A silicon IC that is somewhat complex, fully characterized to operate from -40°C to 200°C and goes through a qualification process to match very tight standards? In my experience I wouldn't expect it to be cheap...The price you see is definitely for low production volume (yes, 1ku/yr is low, especially for automotive) and probably varies a lot if ordered in quantity...

author: helloworld922
author_rank: Regular Contributor
timestamp: March 25, 2013, 02:45:22 pm
content: The first thing that stands out to me is the 200C upper temperature rating. If memory serves me right, typical silicon ICs really doesn't work well above 150C (seems supportedhere, though not a definitive yes/no).Typical automotive grade stuff I've worked with is rated to 125C. If you need to measure temperatures above this usually the sensor is separate and the actual ADC/IC's doesn't need to be rated to the full temperature range (i.e. a K-type thermocouple rated to several hundreds of degrees C with a 125C rated ADC chip that can read the thermocouple).

author: AlphZeta
author_rank: Regular Contributor
timestamp: March 25, 2013, 02:53:15 pm
content: Quote from: helloworld922 on March 25, 2013, 02:45:22 pmThat might be true, and the ceramic packaging may have also increased the cost. But that brought another interesting question, given its relative inaccuracy (+-3degrees) wouldn't it be cheaper and better to just use a thermocouple instead? What's the advantage of this chip that justify its price point?

author: KJDS
author_rank: Super Contributor
timestamp: March 25, 2013, 02:56:40 pm
content: It's in a ceramic hermetic package which are very expensive.

author: AlphZeta
author_rank: Regular Contributor
timestamp: March 25, 2013, 03:02:46 pm
content: Thanks KJDS,Just did a little more research myself, it seems that all those 210C qualified high-temp stuff from TI are around the same price point (http://www.ti.com/hirel/docs/orphan.tsp?contentId=134143)I didn't remember ceramic packing being this expensive. I guess it's the temperature spec plus the packaging make them pricey.

author: free_electron
author_rank: Super Contributor
timestamp: March 25, 2013, 03:55:38 pm
content: half the cost is the CLGA package. this is a very exotic animal.second is the high operating temeprature.. this requires special processes.. combine this with low volume and you end up at exorbitant prices.