When I was recently contacted by SiTime regarding their MEMS oscillators in automobiles, I thought: How many sockets could there be in a car?
Well, take a look at the following:
Image courtesy of SiTime
When I am excited about a product, especially in a hot industry application, and that product can greatly improve the circuit designer’s task of developing a robust circuit design while speeding their time-to-market, then I bring that excitement to my audience. SiTime’s AEC-Q100 qualified MEMS oscillators are such a product.
There are 20-70 oscillator opportunities at $3 to $10 revenue in each car according to SiTime and the advantages of the MEMS oscillator in those harsh environments of extreme temperature and vibration are as follows:
- Best stability ±20 ppm over extended temperature from -55o C to 125o C
- Superior resistance to shock, vibration and noise – 50x better than Quartz oscillators
- Best-in-class quality and reliability over 500MU shipped
- 1.6 DPPM – 30x better quality than Quartz oscillators
- 1,140 MTBF – 30x better reliability than Quartz oscillators
- Best manufacturability
- SOT23 for best solder joint reliability and ease of visual inspection
- EMI control without PCB change with configurable rise/fall time control (See SiTime application note: SiTime Oscillator Rise and Fall Time Selection)
Si Time has the SiT2024/25 and SiT8924/25 oscillators which are robust and, in my estimation, are the best solutions for automotive applications since they are ASIL (Automotive Safety Integrity Level) compliant for advanced driver assistance systems (ADAS), in-vehicle Ethernet, powertrain and electronic control units (ECUs).
Image courtesy of SiTime
Adjusting rise/fall time to reduce Harmonic EMI in automobiles
Multiple rise/fall time options are available on any given device
Today’s automobiles depend more and more on sophisticated electronic control systems making drivers and passengers more comfortable as well as enhancing vehicle safety. It is important that these systems take measures to reduce radiated electromagnetic noise, which could cause interference with on-board or domestic radio reception, and they must reduce susceptibility to the electromagnetic fields that the vehicle will encounter on the road which could compromise vehicle safety.
What are your thoughts and experiences in this area? Please share your comments below to begin a discussion with our audience.