MLX90614 Datasheet, PDF (20/40 Pages) List of Unclassifed Manufacturers – Single and Dual Zone

MLX90614 family
Single and Dual Zone
Infra Red Thermometer in TO-39
8.5.3 Customizing the temperature range for PWM output
The calculated ambient and object temperatures are stored in RAM with a resolution of 0.01 °C (16 bit). The
PWM operates with a 10-bit word so the transmitted temperature is rescaled in order to fit in the desired
range.
For this goal 2 cells in EEPROM are foreseen to store the desired range for To (To_min and To_max) and one for
Ta (Ta_range: the 8MSB are foreseen for Ta_max and the 8LSB for Ta_min).
Thus the output range for To can be programmed with an accuracy of 0.01 °C, while the corresponding Ta
range can be programmed with an accuracy of 2.56 °C.
The object data for PWM is rescaled according to the following equation:
T = ^T _K^{− T} , K = ^T ₁₀^−₂₃^T _PWMobj
RAM
MIN _EEPROM
PWM obj
PWM obj
MAX _EEPROM
MIN _EEPROM
The T_RAM is the linearized Tobj, 16-bit (0000…FFFFh, 0000 for -273.15°C and FFFFh for +382.2°C) and the
result is a 10-bit word, in which 000h corresponds to To_MIN[°C], 3FFh corresponds to To_MAX[°C] and 1LSB
corresponds to ^{ToMAX − ToMIN} [°C]
1023
T_MINEEPORM = T_MIN ∗ 100 LSB
T_MAXEEPORM = T_MAX ∗ 100 LSB
The ambient data for PWM is rescaled according to the following equation:
T = ^T _K^{− T} , K = ^T ₁₀^−₂₃^T _PWMambient
RAM
MIN _EEPROM
PWM_ambient
PWM ambient
MAX _EEPROM
MIN _EEPROM
The result is a 10-bit word, where 000h corresponds to -38.2 °C (lowest Ta that can be read via PWM), 3FFh
corresponds to 125 °C (highest Ta that can be read via PWM) and 1LSB corresponds to ^{TMAX − TMIN} [°C]
1023
[ ( )] T_MINEEPORM = T_MIN − − 38.2
∗ ¹⁰⁰ LSB
64
[ ( )] T_MAXEEPORM = T_MAX − − 38.2
∗ ¹⁰⁰
64
LSB
3901090614
Rev 003
Page 20 of 40
Data Sheet
03/Oct/2007