MLX90614ESF-AAC MELEXIS [Melexis Microelectronic Systems], MLX90614ESF-AAC Datasheet - Page 31

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MLX90614ESF-AAC

Manufacturer Part Number
MLX90614ESF-AAC
Description
Single and Dual Zone Infra Red Thermometer in TO-39
Manufacturer
MELEXIS [Melexis Microelectronic Systems]
Datasheet
11.3 PWM output operation
Using the PWM output mode of the MLX90614 is very simple, as shown on Figure 24.
The PWM mode is free-running after POR when configured in EEPROM. The SCL pin must be forced high
(can be shorted to Vdd pin) for PWM mode operation.
A pull-up resistor can be used to preserve the option for SMBus operation while having PWM as a default as
is shown on Figure 25.
Again, the PWM mode needs to be written as the POR default in EEPROM. Then for PWM operation the
SCL line can be high impedance, forced high, or even not connected. The pull-up resistor R1 will ensure
there is a high level on the SCL pin and the PWM POR default will be active. SMBus is still available (for
example – for further reconfiguration of the MLX90614, or sleep mode power management) as there are pull-
up resistors on the SMBus lines anyway.
PWM can be configured as open drain NMOS or a push-pull output. In the case of open drain external pull-up
will be needed. This allows cheap level conversion to lower logic high voltage. Internal pull-ups present in
many MCUs can also be used.
11.4 Thermal alert / thermostat
The MLX90614 can be configured in EEPROM to operate as a thermal relay. A non contact freezing or
boiling prevention with 1 mA quiescent current can be built with two components only – the MLX90614 and a
3901090614
Rev 003
+5V
C1
0.1uF
3
U1
Vdd
P W M
SDA
2
Vss
4
SCL
Vz
MLX90614Axx
1
-
+
D1
Alert dev ice
Figure 26: Thermal alert/thermostat applications of MLX90614
Figure 24: Connection of MLX90614 for PWM output mode
Figure 25: PWM output with SMBus available
C1
0.1uF
3
U1
Vdd
P W M
SDA
2
Vss
J1
CON1
PWM/SDA
4
J1
CON1
SCL
Vz
MLX90614Bxx
PWM
GND
Vdd
GND
1
SCL
Vdd
Page 31 of 40
R1
C1
2
C1
R2
P W M
SDA
2
SMBus
0.1uF
P W M
SDA
+3.3V
0.1uF
SCL
Vz
Vdd
1
3
SCL
Vz
Vdd
1
3
Vdd
SDA
SCL
GND
Vss
R1
10k
Vss
U1
MLX90614
Infra Red Thermometer in TO-39
U1
MLX90614
U1
MLX90614 family
MCU
Single and Dual Zone
AC line
U2
10uF
C2
C3
0.1uF
R2
3
Vdd
P W M
SDA
Data Sheet
03/Oct/2007
2
Vss
4
SCL
Vz
+24V
1
Q1
R1
C*

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