APGRD003 Microchip Technology, APGRD003 Datasheet - Page 18

• Manufacturer Part Number: APGRD003
• Description: KIT TPMS REFERENCE DESIGN
• Manufacturer: Microchip Technology
• Type: Automotive, Tire Pressure Monitorr

Specifications of APGRD003

• Frequency: 433.92MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: PIC18F4680, PIC18F2680, MCP2030
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

3.4
DS51624B-page 14
TRANSPONDER SENSOR MODULE
3.4.1
3.4.2
3.4.2.1
The microcontroller used is the PIC16F684. The internal 10-bit ADC is used for
pressure, temperature and battery measurements. It also interfaces with the MCP2030
for configuration and LF communications. Other PICmicro MCUs can be selected
based on design requirement.
3.4.2.2
The LF signal processing is handled with the Microchip's three-channel Analog Front
End (MCP2030). The MCP2030 has a user-configurable input filter to process the
incoming LF challenges.
3.4.2.3
The HF transmitter is used for transmitting data to the base station module. A surface
mounted SAW resonator is used to generate the carrier frequency which is controlled
by the output pin of the microcontroller.
3.4.2.4
The sensor implemented in this design is an analog pressure sensor (MS5407-AM)
from Intersema. The two output of the sensor, V+ and V-, will output voltages levels that
correspond to the changes in pressure. The sensor is powered by RA1 pin of the
microcontroller and is in the off state when not taking measurement.
3.4.2.5
The two outputs of the pressure sensors are connected to the differential gain circuitry
using the MCP6273. The output of the differential gain signal is amplified by 10 and
then passed into the 10-bit ADC module in the microcontroller for conversion. The gain
of the signal is controlled by the values of R9, R10, R11 and R12. Refer to
A.13 “Circuit Block Figure”.
Modulation Format:
Encoding Method:
Operating Voltage:
Low Voltage Alert Threshold:
Stand By Current With 3 LF Input
Channels Enabled (PIC & AFE):
UHF Transmitting Frequency:
UHF Transmission Baud Rate (TE): 100, 200, 400, 800 μs selectable,
UHF Range:
LF Frequency:
LF Input Sensitivity:
LF Range:
Pressure Sensor Type:
Pressure Sensor Range:
Pressure Sensor Temperature
Range:
Technical Specifications
Hardware Overview
MICROCONTROLLER
LF RECEIVER (125 kHZ)
HF TRANSMITTER (433.9 MHZ)
SENSOR SIGNAL AMPLIFICATION
PRESSURE SENSOR
ASK
PWM
2.3 - 3.3V
2.3V
~12
433.92 MHz
system default is 400 μs
~ 10 Meters
125 kHz
~3 mVPP
Up to 3 Meters
Analog
1
-40 - 125°C
-7 bars absolute
μ
A
© 2006 Microchip Technology Inc.