MPXY8300 is designed for automobiles and medium/heavy duty trucks, features extremely low power consumption, accurate precision and sensing, and improves the vehicle safety.

1. Published on Your Electronics Open Source (http://dev.emcelettronica.com)
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Freescale MPXY8300: the System-in-Package
TPMS
By slovati
Created Apr 9 2009 - 07:06
MPXY8300 [1] is designed for automobiles and medium/heavy duty trucks, features extremely low power
consumption, accurate precision and sensing, and improves the vehicle safety.
If you want to know more about this Freescale product, please submit your request to Arrow Italy using
this form [2] (this form is valid ONLY for Companies or Customers based in Italy and working in the Italian
area)
MPXY8300 is the Freescale System-in-Package solution (SiP) for Tire Pressure Monitoring System
(TPMS) [3], integrating four silicon devices: 2-axis (X and Z) accelerometers, capacitive pressure sensor,
RF transmitter, and an 8-bit microcontroller.
MPXY8300 is designed to provide a direct measurement of the tire pressure, notifying the driver as soon
as any tire of the vehicle (even the spare one) is not properly inflated. The system has a real-time behavior
an can be programmed to transmit the acquired measures at certain rotation speeds or even when the
tires are not rotating at all.
The MPXY8300 System-in-Package includes the following components:
Pressure and temperature sensors in order to provide a compensated tire pressure measure.
Pressure sensors are available with two pressure range options: 100-800 kPa for automobiles and
100-1500 kPa for heavy-duty trucks
A 20-pin SOIC 8-bit MCU equipped with 512 bytes of RAM and 16 Kb of flash to manage the
sensors monitoring through a time-based scheduler
X and Z-axis accelerometer in order to detect wheel speed and/or direction of rotation
RF transmitter with integrated charge-pump at 315 and 434 MHz, capable of ASK (amplitude-shift
keyed) and FSK (frequency-shifted keyed) modulation schemes with different baud rates
Two-channel low-frequency input with detector/decoder for receiving diagnostic commands and
wake-up function
The following picture gives a representation of the MPXY8300 system: pressure sensor, RF transmitter,
and XZ-axis accelerometer are installed on each tire (the wheel module), whereas the MCU is located in
the vehicle body.

2. The entire device has been engineered to achieve the lowest value of power consumption, since the
device components mounted on each tire are powered by a 3V battery; it has been calculated that under
these circumstances the battery longevity can extend up to ten years.
Pressure measurement is performed with a high level of accuracy thanks to the micromachined capacitive
pressure sensors: these MEMS devices provide a high pressure range together with a minimal power
usage.
The MPXY8300 is available with acceleration sensors providing X-axis sensitivity of +/- 10g and Z-axis
sensitivity with a range from 0 to 60g; three choices are available to the designer: both X- and Z-axis g-
cells, Z-axis g-cell only, or no ?cell at all.
The pressure sensors adopted in MPXY8300 TPMS solution (an example is visible in the following picture)
are absolute surface MEMS sensors in which the capacitance varies with the pressure applied to the top
plate of the sensor, whereas the bottom plate is vacuum-sealed inside the reference chamber of the die
during manufacturing with a zero-pressure reference value.
The Z-axis acceleration sensor is a surface MEMS device which measures the acceleration detecting the
increase in wheel centripetal force; the X-axis acceleration sensor, instead, measures the acceleration
detecting the variations in wheel angular force (Z and X axis orientation is showed in the following
pictures).

3. As mentioned before, MPXY8300 is able to monitor the pressure of all the vehicles tires, including the
spare one. How is it possible to univocally address each tire avoiding any type of collision with the same
TPMS system installed on other vehicles? It is possible adopting an ID which is transmitted with the data:
in this way the receiver can listen only to the specific ID programmed for that vehicle. The ID information
can be up to 96 bits long, is stored in NVM, and its value is assigned during the manufacturing process, in
order to be a unique ID.
On the wheel module there is also a one-channel LF receiver with a frequency of 125 KHz, low power
consumption, and selectable AGC on signal level. Its purpose is to be used for field diagnostics, test
performed in factory, or for tire localization.
The wheel module stays in a very low power mode most of its time in order to preserve as much as
possible the battery power. It wakes up only when the arrival of a LF telegram is detected or when the
programmable internal timer expires; when this happens, data acquired from the sensors is collected,
analyzed, and placed in the buffer for transmission through the RF TX module. The RF module has a
charge pump to generate a higher supply voltage for the RF transmission when the battery power is too
low.
The Freescale MPXY8300 TPMS is a cost-effective solution with low power consumption and high
accuracy; moreover, it is able to provide a precise real-time tire pressure measurement on all the wheels.
Freescale Semiconductor supports also the MPXY8300 developers with a specific TPMS kit consisting of:
a MPXY8300 module, a Freescale ESTAR receiver, and an LF 125 kHz transmitter, plus their associated
software. The tool set is shown in the following picture.
Software can be downloaded on the MPXY8300 and on the LF 125 kHz emitter modules using
MetroWerks CodeWarrior 5.0 or latest and a BDM Multilink as shown below:

4. Read the Italian version: Freescale MPXY8300: il TPMS System-in-Package [4]
CONTACT REQUEST
If you want to know more about this Freescale product, please submit your request to Arrow Italy using
this form [2].
NOTE: this form is valid ONLY for Companies or Customers based in Italy and working in the Italian area.
Hardware MPXY8300 TPMS
Trademarks
Source URL: http://dev.emcelettronica.com/freescale-mpxy8300-system-package-tpms
Links:
[1] http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MPXY8300&fsrch=1
[2] http://it.emcelettronica.com/contact/freescale
[3] http://dev.emcelettronica.com/methods-tire-pressure-monitoring
[4] http://it.emcelettronica.com/freescale-mpxy8300-il-tpms-system-package