Description
MPXY8020A6U Tire Pressure Monitor Sensor, MPXY8020A6U Air Pressure with operating pressure: 36.26 ~ 65.27 PSI, 250 ~ 450 kPa
MPXY8020A6U Tire Pressure Monitor Sensor
Item No. : KR08081
Specifications:
- Operating Pressure: 36.26 ~ 65.27 PSI, 250 ~ 450 kPa ;
- Output: Digital ;
- Package / Case: 8-SOIC (0.295″, 7.50mm Width) ;
- Pressure Type: Absolute ;
- Operating Temperature : -40°C ~ 125°C
Tire Pressure Monitoring Sensor Temperature Compensated and Calibrated, Fully Integrated, Digital Output
The Freescale Semiconductor MPXY8000 series sensor 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 Freescale Semiconductor remote keyless entry (RKE) system to facilitate a low-cost, highly integrated system. DETAILED DESCRIPTION The block diagram of the MPXY8000 series sensor 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 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 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.
TIRE PRESSURE MONITORING SENSOR MPXY8020A: OPTIMIZED FOR 250 kPa 450 kPa MPXY8040A: OPTIMIZED FOR 500 kPa 900 kPa
VDD PX Clock Gen fHF Internal HF OSC. Power Control PREF to V Convert Digital Control S1 S0 Data CLK
OPERATING MODES The device has several operating modes dependent on the applied voltages to the S1 and S0 pins as shown in Table 1. In all the modes listed the channel multiplexers, D/A Register, LFO, and the output pulse dividers will always be powered up as long as there is a voltage source connected to the VDD pin. When only the S0 pin at a logic one the pressure measuring circuit in the device is powered up and the pressure output signal is connected to the sample capacitor through a multiplexer. When the S0 pin returns to the low state the multiplexer will first turn off to store the signal on the sample capacitor before powering down the measuring circuitry. When only the S1 pin at a logic one the temperature measuring circuit in the device is powered up and the temperature output signal is connected to the sample capacitor through a multiplexer. When the S1 pin returns to the low state the multiplexer will first turn off to store the signal
on the sample capacitor before powering down the measuring circuitry. NOTE: All of the EEPROM trim bits will be powered up regardless of whether the pressure or temperature measuring circuitry is activated. NOTE: If the voltage on the S1 pin exceeds 2.5 times the voltage on the VDD pin the device will be placed into its Trim/Test Mode. NOTE: If the VDD supply source is switched off in order to reduce current consumption, it is important that all input pins be driven LOW to avoid powering up the device. If any input pin (S1, S0, DATA, or CLK) is driven HIGH while the VDD supply is switched off, the device may be powered up through an ESD protection diode. Such a case should be avoided. The effective source voltage of the device will be less than the applied voltage due to diode voltage drop. In addition, the entire source current will be drawn from the input pin.
Circuitry Powered S1 S0 Operating Mode Pressure Measure System OFF ON OFF Temp Measure System OFF ON OFF A/D Output Comp. OFF ON LFO Oscill. ON Serial Data Counter
Standby/Reset Measure Pressure Measure Temperature Output Read
PIN FUNCTIONS The following paragraphs give a description of the general function of each pin. VDD and VSS Pins Power is supplied to the control IC through VDD and VSS. VDD is the positive supply and VSS is the digital and analog
ground. The control IC operates from a single power supply. Therefore, the conductors to the power supply should be connected to the VDD and VSS pins and locally decoupled as shown in Figure 2.
To Other VDD Loads VDD To Power Supply VSS To Other VSS Returns
OUT Pin The OUT pin normally provides a digital signal related to the voltage applied to the voltage comparator and the threshold level shifted into an 8-bit register from an external device. When the device is placed in the standby mode the
OUT pin is driven high and will be clocked low when an overflow is detected from a clock divider (divide by 16384) driven by the LFO. This allows the OUT pin to wake up an external device such as an MCU.
RST Pin The RST pin is normally driven high and will be clocked low when an overflow is detected from total clock divider MPXY8000 Sensors Freescale Semiconductor
(divide by 16,777,216) driven by the LFO. This allows the RST pin to reset an external device such as an MCU. This pulse will appear on the RST pin approximately every 52 minutes regardless of the operating mode of the device.
