Swindon Silicon Systems have taken their design expertise and experience developed in the rugged environment of tyre pressure sensors, and applied it to the industrial pressure sensing market. Utilising our proven ultra-low power capability, Swindon can integrate the ASIC with a MEMS pressure sensor, pre-calibrated at test and supplied in a miniature package.
And size matters: the smaller the size, the lower the price.
Better by design – reduced obsolescence
By their very nature and function, industrial pressure sensors tend to be located in difficult to access areas, but are expected to perform accurately for many years. A bespoke design and manufacture ensures there is no compromise in accuracy or performance, and guarantees ongoing protection against obsolescence from a third party manufacturer.
Because Swindon has unrivalled experience in silicon pressure sensor technology, we can design a very accurate (sub ± 1%) bespoke mixed signal (analogue and digital) ASIC with an integrated sensor in less time and at a lower cost than most customers assume.
A flexible low-cost driven business model
While SWINDON Silicon Systems have technology and design expertise in abundance, we also have the flexibility to get things done quickly. As a company, we uniquely combine competitiveness on price as a high volume manufacturer with a dedicated focus on each customer’s particular requirements. “We are large enough to be efficient and small enough to care. And as a business, we are very focused on cost – we are committed to driving down production costs in order to remain competitive on price,” says Engineering Manager, Adrian McDonald.
The Swindon design approach integrates a MEMs pressure sensor with a bespoke mixed signal ASIC that comprises precise analogue circuitry with a microcontroller and programmable software. The sensor is calibrated to each ASIC with the calibrated data being stored in the OTP/flash memory. The analogue signal from the sensor is amplified and then converted into a digital signal for onward transmission by 2/3 wire or RF. In many ways, getting the digital signal to interface correctly is one of the most challenging aspects of the design process. Adrian McDonald expresses the issue succinctly.
“Being able to interface to a system successfully is a difficult job, but it’s an area where our considerable experience in ASIC development really comes into its own.”
Meeting the demands of lower power consumption
To meet the specification of a 10 year life span, powering a silicon tyre pressure sensor, microprocessor and RF transmitter from a single cell lithium battery requires ultra-low power consumption – in fact, between 1µW and a few mW. That is exactly what Swindon has delivered and right now, millions of cars across the world are benefiting from this clever technology. That same ultra-low power consumption and reliability is available now for Industrial Pressure Sensors, where power consumption of 10 mW has previously been considered low. That is an impressive reduction in power of three orders of magnitude.
Tested, tested again and calibrated for accuracy
Testing and calibrating the pressure sensor, over temperature, to the ASIC, is fundamental to the accuracy of the data. By integrating the sensor and ASIC in one package, it’s possible to simultaneously pressure test the sensor and electronics of the ASIC – saving time and ultimately money. SWINDON’s state-of-the-art wafer probe and ATE test facilities at our Wiltshire HQ ensure the highest possible quality control standards are maintained at all times. After double testing, each chip is calibrated before it leaves the premises to ensure the required performance of the device is set prior to delivery to our customer.
As Adrian explains, “At SWINDON we are very unusual in pressure testing and calibrating before the chip leaves the factory and before System Level Testing. This process saves the customer time and potentially money compared with discovering a calibration error during System Level Testing. We worry about the calibration so the customer does not have to.”
Meeting and exceeding demanding EMC requirements
From day one, protection and compatibility are important elements in the design process. Customers understandably worry about the risk of a miswire, a surge in power that could result in a blown chip or the consequences of electrical interference. The Swindon design team ensures that nothing is left to chance, and with protection integrated into the chip, there is no need for any external protection such as an External Diode Bridge. Swindon design and test devices to meet and often exceed relevant industry standards; these include Reversal, Surge, ESD and Conductive Disturbance. In addition, every single ASIC produced has a unique ID which provides traceability back to an individual silicon wafer and batch of wafers.