MLX90313KDF ETC [List of Unclassifed Manufacturers], MLX90313KDF Datasheet - Page 26

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

code 000h will correspond to Tomin, FFFh will correspond to Tomax. These two limits are determined by
calibration. Accordingly the output resolution will be
When reading the linearised data digitally by means of the SPI, a 16-bit word is returned. The 12 MSB’s
contain the temperature value as described above, the 4 LSB’s form a status register, which is the same
for both the IROUT address and the TOUT. The meaning of the individual bits is explained in the table
below.
Linearisation Status Register
S[3:0]
1 X
X 1
X X
X X
*Fatal Error is the uncorrectable error in EEPROM (more than 2 wrong bits per address). When this error
occurs, the normal process flow does not change, but the results may go wrong.
.
The status register is particularly important when an overflow (or underflow) condition occurs for the Ta-
measurement. If the overflow condition occurs IROUT register will be set to FFFh, if underflow - IROUT
wil be 000h. If the user selects to monitor the analogue output through the DAC, then care must be taken
to ensure that Tambient will never exceed the selected range, as the over- or underflow condition is not
flagged.
Comparators and relay output
MLX90313 contains two programmable 12 bit digital comparators. For each circuit the target signal, the
threshold and hysteresis can be programmed in different configurations, according to the table below. The
principle of operation is shown in the following schematics. The threshold and hysteresis values are
stored in eeprom, the control bits are part of the configuration register. The REL1 comparator threshold
can be either read from EEPROM (address 75h) or controlled by an external potentiometer connected to
IROUT. Note that the threshold and hysteresis registers in eeprom are only 11 bits wide. Therefore a zero
is added in the LSB position to the threshold and hysteresis registers, making this register also 12 bits.
MLX90313 Programmable IR sensor Interface
3901090313
Vir
R
X
X
1
X
X
X
X
0
Meaning
Overflow flag for Tambient measurement, Ta>Tamax, TOUT[15:4] set to FFFh
Underflow flag for Tambient measurement, Ta<Tamin, TOUT[15:4] set to 000h
Flag for Fatal Error in eeprom *
Not used, always zero
The r m opile Char acte r is tic
T h e r m is to r ch ar acte r is tic
V ir=f(To, T a)
R=f(T a)
To [d e gC]
T a[d e g C ]
Ta
Lin.
Unit
Page 26
To
Programmable IR Sensor Interface
max To
4096
Linearised output
L in e ar ise d o u tp u t
T e m p o u t= A .T o + B
min
Irout=A.T o+B
T o [degC ]
T a [d eg C ]
in K per LSB.
MLX90313
Rev 1.0 21-July-2001
Irout
Tempout