editor's blog
Subscribe Now

Sensor Conditioning Options

One of the big challenges of MEMS sensor development is the fact that the raw sensor signals need to be conditioned before being read and acted on. This is done in the “ASIC” that ordinarily accompanies the sensor, typically on a separate die and co-packaged with the sensor (unless done on the same chip in a CMOS-friendly MEMS process). A well-known sensor design challenge is the fact that the ASIC has to be designed alongside the sensor, but that, until tools become more accurate, the actual sensor output isn’t known until the sensor has been built (and perhaps after a couple of design spins); that makes it very hard to co-design the ASIC and build it in parallel with the sensor.

Sensors are inherently analog devices, so it takes an analog front end to condition those signals – or at least convert them to digital for further digital processing. If you have a plain sensor with analog outputs and no encapsulated ASIC, then you have to build your own analog conditioning circuit.

Two companies are providing programmable conditioning circuits to avoid both the serial ASIC design issue and the need to build a discrete analog conditioning circuit. They allow a system designer to adjust the tuning of the conditioning network on the target board. This obviously has benefits over doing the manual circuit by hand, and it also means that any effect that the mounting or location of the sensor might have on the sensor output can be factored into the conditioning. Of course, as compared to a sensor with a co-packaged ASIC, it’s an additional chip and work.

Both Si-Ware and Renesas have such chips, Renesas’ recently announced. Si-Ware announced early last summer an actual development platform, the SWS61111, that features their own ASIC chip, the SWS1110. There’s also an FPGA on the board; the system allows a designer to determine the optimal conditioning configuration and then burn it into the ASIC, which has e-fuses for storing a one-time-programmable (OTP) setting.

Meanwhile, Renesas has announced its Smart Analog configurable conditioning circuit. It comes with its own graphic tool to enable tuning without requiring that you be an analog expert. There are two versions: one that it is intended to be paired with a microcontroller, and one that has the microcontroller co-packaged with the Smart Analog part. In both cases, the Smart Analog settings are stored in the microcontroller’s NVM.

You can find more in the earlier Si-Ware release or the more recent Renesas release.

Leave a Reply

featured blogs
Jan 24, 2020
Someone has created a song by taking Pi, assigning each number to a note, and adding harmonies. The result is strangely captivating....
Jan 24, 2020
[From the last episode: We looked at the different ways memory can be organized in different kinds of systems.] Let'€™s look at a scenario: you run a restaurant, but you'€™re short on funds to hire people. So you'€™re your own chief cook and bottle-washer. You do everyt...
Jan 23, 2020
Embedded design trends typically revolve around three main ideas: faster data rates, smaller form factors and cost-effective solutions. Those design trends drive the theme for the 2020 Embedded Tech Trends forum: The Business and Technology Forum for Critical and Intelligent ...
Jan 22, 2020
Master the design and verification of next gen transport: Part One – Overview Master the design and verification of next gen transport: Part Two – High-Level Synthesis Master the design and verification of next gen transport: Part Three – Functional Safety M...

Featured Video

Automotive Trends Driving New SoC Architectures -- Synopsys

Sponsored by Synopsys

Today’s automotive trends are driving new design requirements for automotive SoCs targeting ADAS, gateways, connected cars and infotainment. Find out why it is essential to use pre-designed, pre-verified, reusable automotive-optimized IP to meet such new requirements and accelerate design time.

Drive Your Next Design to Completion Today with DesignWare IP® for Automotive SoCs