MLX90601C Datasheet, PDF (4/12 Pages) List of Unclassifed Manufacturers – SPI IR thermometer module

Datasheet MLX90601C
SPI IR thermometer module
crosses 1.3V. The POR circuit will issue another
reset if the supply voltage goes below 1.3V.
A/D
The MLX90313 on the module contains a 12-bit
internal analog to digital converter. Real 12-bit
conversion is achieved by a fully differential
analog part of the converter. Automatic
calibration is implemented in the background,
which allows precise conversion in a very wide
temperature range.
Comparators
Two comparator circuits are available.
Comparator 1 drives the Rel1 open drain output
and is triggered by the linearised object
temperature signal. The threshold level is
programmed in the eeprom.
Comparator 2 drives the TEMPOUT pin and is
triggered by the linearised object temperature
signal. The threshold level is programmed in
EEPROM and can be changed through the SPI.
Configuration and settings for the comparators
are accessible through the SPI. For details
please refer to the application note on the SPI.
In the second step the value of the ambient
temperature is combined with the measured
signal coming from the IR thermopile sensor
inside MLX90247 to obtain a calculated value for
the object temperature, based on the calibration
data. The value is stored in a dedicated register
and also available for the output electronics and
SPI.
Sensor Characteristics
For detailed specification we refer to the
datasheet on MLX90247, available from the
Melexis website.
In a calibrated module the linearisation unit of
MLX90313 takes all characteristics of the sensor
into account, including all process variations
they are subject to.
The TO-39 sensor housing of the thermopile has
a 2.5mm diameter aperture, resulting in a 70° full
angle field of view.
The silicon filter used as IR-window is treated
with an antireflective coating that will pass
minimum 75% of IR radiation in the wave length
band from 7.5µm to 13.5µm. Below 5µm, 99.5%
of incoming radiation is reflected by the filter
Linearisation Unit
The linearisation unit of MLX90313 realizes 3
functions:
1. Offset measurement and calibration (offset
drift compensation)
2. Measurement and offset cancellation
3. Linearisation.
Linearisation proceeds in two steps. In the first
step the ambient temperature is calculated from
the measured signal coming from the on-chip
PTC temperature sensor of MLX90247. The
value is stored in a dedicated register than is
available for the output electronics.
Serial Peripheral Interface (SPI)
Protocol
The digital interface implemented in MLX90313C
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 command is always 32 bits: 8 bits
for the operation code, 8 bits for the address and
16 bits of data. The communication protocol is
presented below.
CS
SCLK
SDI
SDO
C7 C6 C5 C4 C3 C2 C1 C0 A7 A6 A5 A4 A3 A2 A1 A0 D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
X
X
C7 C6 C5 C4 C3 C2 C1 C0 A7 A6 A5 A4 A3 A2 A1 A0 D15 D14 D13 D12 D11 D10 D9 D8
X
write command
CS
SCLK
SDI
SDO
C7 C6 C5 C4 C3 C2 C1 C0 A7 A6 A5 A4 A3 A2 A1 A0
X
X
C7 C6 C5 C4 C3 C2 C1 C0 D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
X
read command
390109060103
Rev. 004
Page 4 of 12
Dec/01