200 kPa On-Chip Temperature Compensated & Calibrated Pressure Sensors
The MPX2200 series device is a silicon piezoresistive pressure sensor providing a highly accurate and linear voltage output directly proportional to the applied pressure. The sensor is a single monolithic silicon diaphragm with the strain gauge and a thinfilm resistor network integrated onchip. The chip is laser trimmed for precise span and offset calibration and temperature compensation. They are designed for use in applications such as pump/motor controllers, robotics, level indicators, medical diagnostics, pressure switching, barometers, altimeters, etc. Features· Temperature Compensated Over +85°C· ±0.25% Linearity (MPX2200D)· EasytoUse Chip Carrier Package Options· Available in Absolute, Differential and Gauge Configurations Application Examples· Pump/Motor Controllers· Robotics· Level Indicators· Medical Diagnostics· Pressure Switching· Barometers· Altimeters Figure 1 illustrates a block diagram of the internal circuitry on the standalone pressure sensor chip.
VS 3 THIN FILM TEMPERATURE COMPENSATION AND CALIBRATION CIRCUITRY 1 GND
Figure 1. Temperature Compensated Pressure Sensor Schematic VOLTAGE OUTPUT versus APPLIED DIFFERENTIAL PRESSURE The differential voltage output of the sensor is directly proportional to the differential pressure applied. The absolute sensor has a builtin reference vacuum. The output voltage will decrease as vacuum, relative to ambient, is drawn on the pressure (P1) side. The output voltage of the differential or gauge sensor increases with increasing pressure applied to the pressure (P1) side relative to the vacuum (P2) side. Similarly, output voltage increases as increasing vacuum is applied to the vacuum (P2) side relative to the pressure (P1) side.
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)
Characteristics Pressure Range(1) Supply Voltage Supply Current Full Scale Span(3) Offset(4) Sensitivity Linearity(5) MPX2200D Series MPX2200A Series to +125°C) Symbol POP VS Io VFSS Voff V/P TCVFSS TCVoff Zin Zout tR Min Typ Max Unit kPa Vdc mAdc mV mV/kPa %VFSS mV ms %VFSS
Pressure to 200 kPa) Temperature Effect on Full Scale Span(5) Temperature Effect on Input Impedance Output Impedance Response to 90%) WarmUp Offset Stability(7) Offset(5)
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.
LINEARITY Linearity refers to how well a transducer's output follows the equation: Vout = Voff + sensitivity x P over the operating pressure range. There are two basic methods for calculating nonlinearity: (1) end point straight line fit (see Figure (2) a least squares best line fit. While a least squares fit gives the "best case" linearity error (lower numerical value), the calculations required are burdensome. Conversely, an end point fit will give the "worst case" error (often more desirable in error budget calculations) and the calculations are more straightforward for the user. Motorola's specified pressure sensor linearities are based on the end point straight line method measured at the midrange pressure.
LEAST SQUARES FIT RELATIVE VOLTAGE OUTPUT EXAGGERATED PERFORMANCE CURVE
Figure 3 shows the output characteristics of the MPX2200 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.
DIFFERENTIAL/GAUGE STAINLESS STEEL DIE METAL COVER P1 EPOXY CASE
STAINLESS STEEL METAL COVER EPOXY CASE
Figure 4. CrossSectional Diagrams (Not to Scale) Figure 4 illustrates an absolute sensing die (right) and the differential or 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 MPX2200 series pressure sensor operating 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.