MLX90616 Datasheet, PDF (30/36 Pages) Melexis Microelectronic Systems – Infra Red Thermometer in TO-39 for high temperature thermometer guns

MLX90616ESF-HCA
Infra Red Thermometer in TO-39
for high temperature thermometer guns
11.3 PWM output operation
Using the PWM output mode of the MLX90616 is very simple, as shown in Figure 22.
J1
Vdd
PWM
GND
CON1
1
SCL
Vz
PWM
2 ^SDA
Vss
Vdd
U1
MLX90614
C1
3
0.1uF
Figure 22: Connection of MLX90616 for PWM output mode
The PWM mode is free-running after POR when configured in EEPROM. The SCL pin must be forced high
for PWM mode operation (can be shorted to V_DD pin).
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 23.
J1
Vdd
SCL
PWM/SDA
GND
CON1
R1
10k
1
SCL
Vz
PWM
2 ^SDA
Vss
Vdd
U1
MLX90614
C1
3
0.1uF
Figure 23: PWM output with SMBus available
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 MLX90616, 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.
3901090616
Rev 002
Page 30 of 36
Data Sheet
August 20, 2012