MLX90313KDF ETC [List of Unclassifed Manufacturers], MLX90313KDF Datasheet - Page 28

• Manufacturer Part Number: MLX90313KDF
• Description: Programmable IR Sensor Interface
• Manufacturer: ETC [List of Unclassifed Manufacturers]

The threshold data can be calculated by the formula:
where: Tthr is the target temperature for the comparator
The hysteresis value can be calculated by following formula:
where: Thys is the desired hysteresis in deg C.
Both formulas are valid for ambient and IR temperatures. The data for hysteresis must be stored at
addresses 74h (for Comp1) and 76h (for Rel1) after adding the hamming bits in the 5 least significant bit
places. Refer to Hamming Coding in eeprom description section for details.
Pulse Width Modulation
The PWM signal has a period of 102.4ms typical consisting of 2048 clock cycles of 50 s. Every frame
starts with a leading buffer time, t
The leading buffer time is followed by a slot for the useful data signal, t2 and t3, where the ration t2/(t2+t3)
is the representation of the output value. t4 is a slot for signaling of special conditions, such as out of
range measurement of the sensor temperature, Tambient and the occurrence of a fatal EEprom error, i.e.
an error that can no longer be corrected automatically by the ECC circuitry of MLX90313.
Condition
OVH: Tambient overflow
OVL: Tambient underflow
FE: Fatal Error EEprom
Serial Interface
Protocol
The digital interface implemented in MLX90313 is SPI compatible. It can be used to access the on-chip
EEPROM and all internal registers. The chip will always work as a slave device. The format of any
MLX90313 Programmable IR sensor Interface
3901090313
output signal
0
Threshold value =
Tmin, Tmax are the minimum and maximum temperature under calibration.
Hysteresis value =
Tmin, Tmax are the minimum and maximum temperature under calibration
t
1
Error signaling band
1
8
T
Duty cycle
68.75 %
75 %
81.25%
T
T
Tthr
max T
max
Valid Data Output Band
Thys
1
, during which the signal is always high, as shown in the figure below.
nominal timing
70.4 ms
76.8 ms
83.2 ms
T
T
min
min
min
t
2
+t
3
2048
2048
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Programmable IR Sensor Interface
8
5
T
t
4
:Error Signaling Band
16
11
T
12
16
T
MLX90313
13
16
Rev 1.0 21-July-2001
T
7
8
T
t
5
time
T