MPXY8020A_03 Datasheet, PDF (1/16 Pages) Freescale Semiconductor, Inc – Tire Pressure Monitoring Sensor Temperature Compensated and Calibrated, Fully Integrated Digital Output

MOTOROLA
Freescale Semiconductor, Inc.
SEMICONDUCTOR TECHNICAL DATA
Order this document
by MPXY8020A/D
Tire Pressure Monitoring Sensor
Temperature Compensated and
Calibrated, Fully Integrated,
Digital Output
GENERAL DESCRIPTION
The Motorola MPXY8020A is an 8–pin tire monitoring sensor which is
comprised of a variable capacitance pressure sensing element, a temperature
sensing element, and an interface circuit (with a wake–up feature) all on a
single chip. It is housed in a Super–Small Outline Package (SSOP), which
includes a media protection filter. Specifically designed for the low power
consumption requirements of tire pressure monitoring systems, it can combine
with a Motorola remote keyless entry (RKE) system to facilitate a low–cost
highly integrated system.
Detailed Description
The block diagram of the MPXY8020A is shown in Figure 1. The pressure
sensor is a capacitive transducer constructed using surface micromachining,
the temperature sensor is constructed using a diffused resistor, and the
interface circuit is integrated onto the same die as the sensors using a standard
silicon CMOS process.
The conditioning of the pressure signal begins with a capacitance to voltage
conversion (C to V) followed by a switched capacitor amplifier. This amplifier
has adjustable offset and gain trimming. The offset and gain are factory
calibrated, with calibration values stored in the EEPROM trim register. This
amplifier also has temperature compensation circuits for both sensitivity and
offset, which also are factory–adjusted using the EEPROM trim register.
The pressure is monitored by a voltage comparator, which compares the
measured value against an 8–bit threshold adjusted by a serial input. By
adjusting the threshold and monitoring the state of the OUT pin the external
device can check whether a low–pressure threshold has been crossed, or
perform up to 8–bit A/D conversions.
The temperature is measured by a diffused resistor with a positive
temperature coefficient driven by a current source, thereby creating a voltage.
The room temperature value of this voltage is factory–calibrated using the
EEPROM trim register. A two–channel multiplexer can route either the
pressure or temperature signal to a sampling capacitor that is monitored by a
voltage comparator with variable threshold adjust, providing a digital output for
temperature.
An internal low frequency, low power 5.4 kHz oscillator with a 14–stage
divider provides a periodic pulse to the OUT pin (divide by 16384 for 3
seconds). This pulse can be used to wake up an external MCU to begin an
interface with the device. An additional 10–stage divider will provide a pulse
every 52 minutes which can be used to reset an external MCU.
The power consumption can be controlled by several operational modes
selected by external pins.
MPXY8020A
TIRE PRESSURE MONITORING
SENSOR
OPTIMIZED FOR 250 kPa – 450 kPa
SUPER SMALL OUTLINE PACKAGE
CASE 1352
ORDERING INFORMATION
Shipped in Rails Shipped in Tape & Reel
MPXY8020A6U
MPXY8020A6T1
REV 1.0
©
Motorola Sensor
Motorola, Inc. 2003
Device
Data
For More Information On This Product,
1
Go to: www.freescale.com