Design Problem #1: A Pressure Sensor Cluster

Design a cluster of piezoresistive pressure sensors for measurement of fluctuating pressure on an airfoil. The cluster consists of a row of 48 sensors: 43 absolute type pressure sensors and 5 absolute pressure sensors with collocated temperature sensors. The cluster sensors are on a silicon substrate surface area of 15 mm x 12 mm.

1. Pressure range: +/- 20 psia (Absolute pressure)
2. Sensitivity: 2mV/V/psi minimum
3. Frequency bandwidth: 25KHz minimum
4. Pressure resolution: 0.001psi maximum
5. Maximum overpressure: 60psi
6. Each pressure sensor is 200 microns square
7. Sensor-to-sensor pitch is 200 microns
8. Overall accuracy: Better than 0.1% of FSO (Including linearity, thermal stability, thermal coefficient of sensitivity, repeatability, zero shift, and 30-day long-term stability)
9. Maximum surface undulation: 10 micrometers
10. Electrical leads must be passivated with insulating layer; only contact pads are exposed
11. Etched chambers are evacuated (vacuum) and sealed individually to a silicon substrate of the same type and orientation for matching coefficients of thermal expansion
12. Power and ground lines are rated at 24mA minimum
13. Signal lines are rated at 1mA
14. The cluster layout requirements are shown below
15. The cluster dimensions are 15mm x 12mm x ~ 0.5mm
16. See the attached for the suggested cluster layout details