Pressure Sensors, Transducers - MPXA6115AC6U application field and working principle

Pressure measurement is an important part of many engineering applications. Whether controlling process or tracking performance, pressure sensors are invaluable in countless applications. The Freescale MPXA6115AC6U is an integrated pressure transducer with integrated circuit (IC) technology. It is designed for harsh environment applications including automotive, transports, HVAC and more. This transducer is a cost-effective pressure sensing solution and offers superior accuracy over a wide temperature range.

Overview

The Freescale MPXA6115AC6U is an all-in-one integrated silicon pressure sensor and transducer with discrete analog electronics. It is based on Freescale’s proven gauge type pressure sensing technology and enables advanced system level accuracy without the need for offset compensation or other form of calibration. It features internal isolation between the pressure microsensor and the signal conditioning circuitry, which isolates the microsensor from environmental conditions for optimized long term stability.

The Freescale MPXA6115AC6U is capable of measuring pressure from 0 to 125 psi with an accuracy of 0.5% or better over temperature. It offers an offset voltage of 0.1 to 0.4 volts, depending on the output voltage range. The output signal is proportional to the pressure in the gas or potentiometer and is linearized by a sensing element. The entire transducer is hermetically sealed in a miniature, SMD, 5-pin package to resist shock, vibration and environmental extreme.

Features

• High accuracy and precision
• Fast response time
• Compact and lightweight design
• Industry standard 5-pin SIP package
• Reverse voltage and short circuit protection
• Wide operating temperature range (-40 to 125 ºC)
• Capacitive sensing element with optional calibration
• High Output Push-Pull, NPN/PNP, and PWM outputs

Applications

The Freescale MPXA6115AC6U is designed to be used in a wide variety of harsh-environment applications including automotive, marine, transport, HVAC, and general industrial devices. It is suitable for a wide range of pressure measurement and control applications such as engine intake and exhaust pressure, turbocharger boost, industrial HVAC and fluid systems, and fire alarm systems. The device can also be used for high accuracy applications such as medical devices, hydraulic pressure monitoring, fuel level sensing, and industrial automation.

Working Principle

The Freescale MPXA6115AC6U is a capacitive silicon pressure transducer. It uses a multi-stage temperature compensation scheme in conjunction with a custom designed sensing element to accurately measure pressures from 0-125 PSI. The signal conditioning circuitry amplifies the signal generated by the sensor and filters out any noise or interference introduced by the system. The amplified, filtered signal is then amplified further and conditioned to meet desired specifications.

The sensing element consists of two thin film barriers located between two metal plates, which form two capacitor plates. The pressure applied to the sensing element causes the two barriers to move closer together or farther apart depending on the pressure, thus causing a change in the capacitance between the plates. The pressure change is then converted into an electrical signal that is proportional to the change in pressure.

The transducer also features an internal temperature sensor that is used to compensate for temperature changes that could affect the accuracy of the pressure measurement. The temperature sensor is connected to a precision analog-to-digital converter which measures the absolute temperature and ensures that the output signal is linear over the entire temperature range. This allows the transducer to be highly accurate over a wide temperature range of -40 to 125 ºC.

Conclusion

The Freescale MPXA6115AC6U is a versatile, cost-effective pressure sensor and transducer solution. It features fast response time, high accuracy and precision, and a wide operating temperature range. The integrated silicon pressure transducer uses a custom designed sensing element to accurately measure pressure and features temperature compensation to ensure accuracy over a wide range. It is ideal for a variety of applicaitons including automotive, industrial, medical, and marine.