MEMS Pressure Sensor From Freescale

Freescale Semiconductor, Inc. has introduced its first digital output pressure sensor to help simplify system design and enable increased memory storage density for hard disk drives (HDD) used in laptops and PCs. Based on micro-electromechanical systems (MEMS) technology, the MPL115A digital sensor provides high-accuracy barometric and altimetry functions in a compact package for a variety of cost-sensitive consumer and industrial applications.

In addition to barometric pressure sensing in HDD, barometry and altimeter applications, the MPL115A pressure sensor offers absolute pressure measurement for industrial equipment, such as desktop weather stations and vacuum equipment. Medical applications include health monitoring, wound management and respiratory systems. With the rise in demand for safety and security products, the MPL115A adds another dimension of environmental sensing via ambient pressure measurement and is also capable of wireless remote monitoring.

“In an effort to serve our pressure sensor customers in applications such as altimeters, hard disk drives and portable medical equipment, we’ve delivered an innovative sensor solution that incorporates an easy-to-use digital interface, small package and low-power operation,” said Demetre Kondylis, vice president and general manager of Freescale’s Sensor and Actuator Solutions Division. “The MPL115A digital pressure sensor is available in one of our most compact packages, which helps save board space. And, its power consumption is lower than similar pressure sensors on the market today.”

About the MPL115A digital pressure sensor
Freescale’s MPL115A digital pressure sensor can communicate on inter-integrated circuit (I2C) and serial peripheral interface (SPI) buses, providing a direct connection to the embedded system microcontroller (MCU) for communication simplicity and flexibility. This architecture differs from most pressure sensors that communicate using analog signals and require an MCU with an on-chip analog-to-digital converter (ADC) or a separate ADC component within the system. Digital pressure sensors such as Freescale’s MPL115A provide additional flexibility and cost savings by eliminating the need for an ADC.

The MPL115A sensor’s low-profile 3 x 5 x 1.2 mm LGA package enables increased integration and makes the device ideal for portable applications where board space-savings is important. Battery- and solar-powered applications benefit from the device’s low current consumption at 1 microamp in sleep mode and 5 microamps in active mode. The digital sensor is well-suited for HDD systems where pressure measurement is used to optimize the pickup head ride height, which helps maximize the storage capacity of the disk.

The MPL115A system includes a pressure sensor and a conditioning IC housed within a low-profile package. The conditioning IC contains a temperature sensor with an ADC, read-only memory (ROM) for coefficient storage and a simple I2C/SPI slave interface.

Energy efficiency
The MPL115A sensor has been designed with energy efficiency in mind. It offers improved performance and is engineered to deliver up to 100 times less energy consumption than competing products. To conserve power, the device has special operational modes that allow designers to manage power consumption, based on the needs of their applications, by switching between these modes. For instance, the energy-saving standby mode acts as the default, and active mode occurs only during measurement before returning to standby mode.

MPL115A sensor product features:

• Digital output options
• MPL115A1T1 for SPI applications
• MPL115A2T1 for I2C applications
• Low-profile 3 x 5 x 1.2 mm LGA metal package
• Low current consumption
• Sleep mode: 1 microamp
• Active mode: 5 microamps at one measurement per second
• Temperature and pressure coefficients available for temperature compensation
• Convenient pressure conversion in units of kiloPascals (kPa)
• 50 to 115 kPa absolute pressure measurement range
• 1 kPa accuracy
• Operating temperature range from -40ºC to 105ºC
• 2.4 to 5.5 Volt power supply

Development support, pricing and availability
MPL115A samples are available through the following evaluation kits. The KITMPL115A1SPI evaluation board demonstrates the SPI communication protocol. The KITMPL115A2I2C evaluation board demonstrates the I2C communication protocol. Both evaluation kits are at a suggested resale price of $15 (USD). The MPL115A1T1 sensor for SPI applications and MPL115A2T1 sensor for I2C applications are available for a suggested resale price of $4.25 (USD) in 10,000-piece quantities.