mlx90603 Melexis Company, mlx90603 Datasheet - Page 13

• Manufacturer Part Number: mlx90603
• Description: Tire Pressure Monitoring Sip Low-power Pressure Sensor
• Manufacturer: Melexis Company

7.3.5 Battery life time calculation example
The timers, the microcontroller, the ADC and the sensors are guaranteed to operate up to 150C.
The temperature sensor works monotonously up to 150C. The MLX90603 can be programmed to go to
Sleep Mode without measuring, when the temperature rises above a defined value, it can restart measuring
when the temperature is again below this limit.
3901090603 Rev.002
7.4 Temperature shut down
1. One Pressure + one Temperature measurement every 3 seconds
2. One RF transmission every 30 sec, using messages of 10 bytes (80 bits) and 10kbps FSK.
3. Standby current depends on the choice of motion sensor:
4. Using a CR2450 battery with 540mAH capacity.
In the table below the battery life time is estimated based on the above simplified example.
(*) Assumption that vehicle is driving during 5% of the time, so that sensor measurements and RF
transmissions are active only 5% if motion detection is used. Without motion detection, the
measurements and transmissions must be done 100% of the time.
(**) In typical cases not the full rated battery capacity can be used. Therefore a battery life time for
60% of the rated capacity is estimated.
Wake up
The TH720xx transmitter at 3dBm RF power consumes 7mA and takes 1.5ms to start up.
a. No motion sensor:
b. With mechanical motion switch
c. With MFD for LF initiation
=> assume 1%/yr leakage, this consumes I
(no motion detect)
I
consumption per message: 7ma * (8ms+1.5ms) = 66.5 uAs
Average transmit current: I
MEAS
Timer
4.88
12.6
7.6
= (2.22uAs + 2.35uAs) / 3s = 1.52 uA
Page 13 of 18
I
I
I
Mechanical
SLEEP
SHELF
SLEEP+MFD
switch
1.03
59.8
35.9
LEAK
=
=
TX
Tire Pressure Monitoring SiP
Low-Power Pressure Sensor
= 0.62uA
= 66.5uAs/30s =
=
LF initiator
0.52uA
0.22uA
0.57uA
1.38
44.7
26.8
MLX90603
2.22 uA
19 July 2007