mlx90601b Micrel Semiconductor, mlx90601b Datasheet - Page 4

• Manufacturer Part Number: mlx90601b
• Description: Analog Ir Thermometer Module
• Manufacturer: Micrel Semiconductor

Detailed Description
Analog Features
Supply
The module should be supplied directly with a
nominal 5V regulated supply on pin VDD. (4.5V
– 6V)
The power-on reset circuitry is internal to
MLX90313. The module is fully operational 16
ms from the time the supply 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
analog to digital converter. True 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.
D/A
An 8-bit digital to analog converter is used to
output the data for the linearised Tobject- and
Tambient signals.
Output drivers
The IROUT and TEMPOUT pin drivers can
source 1mA and sink 20 A and are reverse
voltage protected down to –5V relative to VSS.
REL1 is an open drain relay driver output
controlled by the comparator circuitry of
MLX90313. The digital comparator’s threshold
(25 C) and hysteresis (2 C) are preset from
factory. The comparator uses Tobject as input
signal.
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.
390109060101
Rev. 004
Page 4 of 8
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,
controlling the output electronics.
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 from there available for the output
electronics.
Note that on request any arbitrary linearisation
curve can programmed. A very wide range of
applications can be covered by MLX90601
family.
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 7.5 m to 13.5 m. Below 5 m, 99.5%
of incoming radiation is reflected by the filter.
Pin Descriptions
IROUT
IRout analog voltage output pin. The voltage at
this pin is a linear representation of Tobject, the
temperature of the object the IR sensor is
pointed at. The driver can source at least 1mA
and sink at least 20 A to/from an external load.
TEMPOUT
Tempout analog voltage output pin. The voltage
Analog IR thermometer module
Datasheet
MLX90601B
Dec/01