EVB90129 Datasheet, PDF (9/13 Pages) Melexis Microelectronic Systems – Asset management and monitoring (security and integrity)

EVB90129
MLX90129 Evaluation Board
4.3 External temperature sensor
The external temperature sensor is a thermistor of
1KOhm with an operating temperature range from -40 to
+125 degrees Celsius. The output voltage monitored by
SENS 3 corresponds to SENSSUP1 divided per 2 plus
the variation of the sensor. This voltage will be compared
with VCM (SENSSUP1 divided by 2) value internally of
the MLX90129. The datasheet gives more information
about this setup. To be used, all the jumpers of the
CON7/ TEMP_SELECTOR have to be set in order to
connect MLX90129 pins SENSSUP1 and SENS3 to the
sensor. The schematic shows the sensor implementation
and the following register configuration allows monitoring
the ambient temperature through the MLX90129.
SENS3
SENSSUP1
CON7
43
21
TEMP_SELECTOR
R8
10K
R12
1K
R9
10K
GND
Content
Control word
Low threshold
High threshold
Conditioner config.
Connection config.
Resistance network
# Hexa 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
15 C070 1 1 0 0 0 0 0 0 0 1 1 1 0 0 0 0
16 0000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
17 0000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
18 0000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
19 0123 0 0 0 0 0 0 0 1 0 0 1 0 0 0 1 1
1A 0040 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0
4.4 Potentiometer sensor
The external trimmer is a 100 Ohm variable resistor. The
output voltage monitored by SENS 4 corresponds to
SENSsUP1 divided per 2 plus the variation of the sensor.
This voltage will be compared with VCM (SENSSUP1
divided by 2) value internally of the MLX90129. The
datasheet gives more information about this setup.
To be used, all the jumpers of the CON8/
TRIM_SELECTOR have to be set in order to connect
MLX90129 pins SENSSUP1 and SENS4 to the sensor.
The schematic shows the sensor implementation and the
following register configuration allows monitoring the
variation of trimmer resistivity through the MLX90129.
SENS4
SENSSUP1
CON8
43
21
TRIM_SELECTOR
R10
10K
2 R13
100R
R11
10K
GND
Content
Control word
Low threshold
# Hexa 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
15 C070 1 1 0 0 0 0 0 0 0 1 1 1 0 0 0 0
16 0000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
High threshold
Conditioner config.
Connection config.
17 0000
18 0000
19 0069
0 0 0 0 0 0 0000000000
0 0 0 0 0 0 0000000000
0 0 0 0 0 0 0001101001
Resistance network 1A 0040 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0
390129012901
Rev 003
Page 9 of 13
Evaluation Board
June-2010