Freescale Semiconductor introduced the FXTH87 tire pressure monitoring system (TPMS) family, which is the smallest integrated package
TPMS solution available at an extremely light weight of 0.3 grams. The FXTH87 family is 50 percent smaller than competing products, helping designers reduce overall bill of materials costs. Freescale’s newest TPMS system-in-package solution provides low power consumption combined with the highest level of functional integration in one package, featuring a dual-axis accelerometer architecture, pressure and temperature sensor, integrated MCU, RF transmitter and low frequency receiver.
The National Highway Traffic Safety Administration estimates that 23,000 accidents and 535 vehicle fatalities occur each year involving flat tires or blowouts, which TPMS systems help prevent by ensuring proper tire inflation monitoring. In addition, properly inflated tires improve fuel economy and reduce emissions, resulting in many regions worldwide, including the United States, European Union, China, Japan and Taiwan, to begin requiring TPMS in new vehicles. According to IHS iSuppli, TPMS will represent more than 25 percent of the total pressure measurement market for automotive sensors by 2015.
Enclosed in a 7 x 7 x 2.2 mm package, the FXTH87 family provides the smallest footprint available, enabling form factors ideal for tire pressure sensor module developers to reduce the weight and overall bill of materials costs. The industry’s lowest RF power consumption at 7mA ldd significantly extends battery life. Both the single- and dual-axis accelerometer options improve accuracy and facilitate more precise tire localization implementation and universal interoperability for original equipment manufacturers and aftermarket applications. And the integrated MCU and dedicated firmware offer the largest customer flash memory at 8 KB, increasing application flexibility and reducing time to market.
• QFN 7 × 7 × 2.2 mm package enables visible solder joint for inspection
• 100–450 kPa and 100–900 kPa pressure ranges
• Z-axis or dual XZ-axis accelerometers
• Accelerometer standard or precision tolerances available
• Low-power wake-up timer and periodic reset driven by LFO
• Dedicated state machines for reduced power consumption
• 8-bit MCU/S08 core with SIM, interrupt and debug/monitor
• 512 Bytes RAM / 16 k Flash (8 k for Freescale library, 8 k for applications)
• Internal 315/434 MHz RF transmitter
• Internal 125 kHz LF receiver
• Six multipurpose GPIO pins (including two A/D inputs)