The Fujikura AP3 and AG3 series: high-precision MEMS pressure sensors with an outstanding signal-to-noise ratio (SNR)
The AG3 and AP3 series were developed originally for highly accurate measurement of blood pressure, and have since been installed in professional blood pressure devices in large volumes. Now it has been shown that the sensor, which features an exceptionally low-noise analogue output signal, also has important advantages for other uses; for example, medical technology applications, such as dialysis or treatment of DVT – anywhere where excellent resolution and a fast sampling rate are required. Our customers have shown through their applications that true 16-bit resolution at a proper AD conversion is possible. All 16 bits can be evaluated – with no fuzzy bits – which is unique in the market for PCB-based pressure sensors of this size. Fujikura achieves this through a unique signal processing and amplification that differs significantly from competitor products. Due to the high quantity and highly automated production with Japanese quality and a rejection rate of nearly 0%, the sensor has an almost unbeatable price-performance ratio.
The analog AG3 & AP3 series is a two-chip system consisting of a MEMS sensor chip and a signal-conditioning chip. The signal conditioning IC does not have A/D and D/A converter steps in the gain amplifier, and the amplification is designed with a very low noise output. As a unique function, the AG3 and AP3 also have single point pressure threshold detection. Analog output from the pressure measurement and a threshold voltage are supplied to an internal comparator that compares the two voltages. The digital output isa comparison results.
One very popular application of the AG3 and AP3 series is for high-end non-invasive blood pressure (NiBP) monitoring devices, where the low noise amplification gives a huge benefit across the whole range of measured blood pressures. With proper filtering the peak to peak noise is well below 0.02 mmHg.
Another application of growing importance is the single point pressure threshold detection option. This function allows the design of very small and cheap pressure switches and activates a switch or detects activity. This is very important for applications with space restrictions or for small, lightweight constructions where pressure is monitored.
The standard measurement ranges between 0 and 250 mbar and 0 and 12 bar; non-standard ranges are possible on request. The pressure range is configurable as positive, negative or bidirectional gauge, and the supply voltage is configurable at 3.0, 3.3 or 5.0 VDC. The pressure sensors are delivered in the usual high quality Fujikura packages comprising tray, tape and reel and stick, according to customer’s specification.