10 kPa On-Chip Temperature Compensated & Calibrated Silicon Pressure Sensors
The MPX2010/MPXV2010G series silicon piezoresistive pressure sensors provide a very at e and tl y proportional to the applied pressure. These sensors house a single monolithic silicon die with the strain gauge and thinfilm resistor network integrated on each chip. The sensor is laser trimmed for precise span, offset calibration and temperature compensation. Features· Temperature Compensated over to +85°C· Ratiometric to Supply Voltage· Differential and Gauge Options Application Examples· Respiratory Diagnostics· Air Movement Control· Controllers· Pressure Switching Figure 1 shows a block diagram of the internal circuitry on the standalone pressure sensor chip.
VS 3 THIN FILM TEMPERATURE COMPENSATION AND CALIBRATION CIRCUITRY 1 GND
COMPENSATED PRESSURE SENSOR to 10 kPa to 1.45 psi) FULL SCALE SPAN: 25 mV
Figure 1. Temperature Compensated and Calibrated Pressure Sensor Schematic VOLTAGE OUTPUT versus APPLIED DIFFERENTIAL PRESSURE The output voltage of the differential or gauge sensor increases with increasing pressure applied to the pressure side (P1) relative to the vacuum side (P2). Similarly, output voltage increases as increasing vacuum is applied to the vacuum side (P2) relative to the pressure side (P1).
Preferred devices are Motorola recommended choices for future use and best overall value.
Motorola Sensor Device Data © Motorola, Inc. 2002
Rating Maximum Pressure > P2) Storage Temperature Operating Temperature Symbol Pmax Tstg TA Value to +125 Unit kPa °C
NOTE: Exposure beyond the specified limits may cause permanent damage or degradation to the device.
OPERATING CHARACTERISTICS (VS = 10 Vdc, = 25°C unless otherwise noted, > P2)
Characteristic Pressure Supply Range(1) Symbol POP VS Io VFSS Voff V/P to 10 kPa) +125°C) Span(5) TCVFSS TCVoff Zin Zout 90%) tR Min Typ Max Unit kPa Vdc mAdc mV mV/kPa %VFSS mV ms %VFSS
Supply Current Full Scale Offset(4) Sensitivity Linearity(5) Pressure Hysteresis(5) Span(3)
Temperature Effect on Full Scale Temperature Effect on Offset(5) Input Impedance Output Impedance Response WarmUp Offset Stability(7) Time(6)
NOTES: 1. kPa (kiloPascal) equals 0.145 psi. 2. Device is ratiometric within this specified excitation range. Operating the device above the specified excitation range may induce additional error due to device selfheating. 3. Full Scale Span (VFSS) is defined as the algebraic difference between the output voltage at full rated pressure and the output voltage at the minimum rated pressure. 4. Offset (Voff) is defined as the output voltage at the minimum rated pressure. 5. Accuracy (error budget) consists of the following:· Linearity: Output deviation from a straight line relationship with pressure, using end point method, over the specified pressure range.· Temperature Hysteresis: Output deviation at any temperature within the operating temperature range, after the temperature is cycled to and from the minimum or maximum operating temperature points, with zero differential pressure applied.· Pressure Hysteresis: Output deviation at any pressure within the specified range, when this pressure is cycled to and from the minimum or maximum rated pressure, at 25°C.· TcSpan: Output deviation at full rated pressure over the temperature range to 85°C, relative to 25°C.· TcOffset: Output deviation with minimum rated pressure applied, over the temperature range to 85°C, relative 25°C. 6. Response Time is defined as the time for the incremental change in the output to go from 90% of its final value when subjected to a specified step change in pressure. 7. Offset stability is the product's output deviation when subjected to 1000 hours of Pulsed Pressure, Temperature Cycling with Bias Test.
Figure 2 shows the output characteristics of the MPX2010/MPXV2010G series at 25°C. The output is directly proportional to the differential pressure and is essentially a straight line. The effects of temperature on full scale span and offset are very small and are shown under Operating Characteristics.
This performance over temperature is achieved by having both the shear stress strain gauge and the thinfilm resistor circuitry on the same silicon diaphragm. Each chip is dynamically laser trimmed for precise span and offset calibration and temperature compensation.
STAINLESS STEEL METAL COVER EPOXY CASE
Figure 3. Unibody Package CrossSectional Diagram (not to scale)
Figure 3 illustrates the differential/gauge die in the basic chip carrier (Case 344). A silicone gel isolates the die surface and wire bonds from the environment, while allowing the pressure signal to be transmitted to the silicon diaphragm. The MPX2010/MPXV2010G series pressure sensor oper-
ating characteristics and internal reliability and qualification tests are based on use of dry air as the pressure media. Media other than dry air may have adverse effects on sensor performance and long term reliability. Contact the factory for information regarding media compatibility in your application.