Data Sheet

MLX90614 family
Single and Dual Zone
Infra Red Thermometer in TO-39
3901090614 Page 39 of 52 Data Sheet
Rev 008 February 28, 2013
11 Applications Information
11.1 Use of the MLX90614 thermometer in SMBus configuration
SCL
Vz
Vdd
R2
2
C1
0.1uF
3
U1 MCU
SCL
SDA
GND
Vdd
4
+3.3V
PW M
SDA
U2
MLX90614Bxx
R1
1
SMBus
Vss
Figure 35: MLX90614 SMBus connection
Figure 35 shows the connection of a MLX90614 to a SMBus with 3.3V power supply. The MLX90614
has diode clamps SDA / SCL to Vdd so it is necessary to provide MLX90614 with power in order not to load the
SMBus lines.
11.2 Use of multiple MLX90614s in SMBus configuration
R2
U1
MLX90614Bxx
4
1
2
SCL
Vz
U1
MLX90614Bxx
C4
Cbus2
U1 MCU
SCL
SDA
GND
Vdd
1
I1
Ipu1
C2
0.1uF
SCL
Vz
3
SDA
C3
Cbus1
R1
3
SCL
4
C1
0.1uF
Vss
+3.3V
I2
Ipu2
Vdd
Vdd
2
SMBus
Vss
Current source or resistor
pull-ups of the bus
PW M
SDA
PW M
SDA
Figure 36: Use of multiple MLX90614 devices in SMBus network
The MLX90614 supports a 7-bit slave address in EEPROM, thus allowing up to 127 devices to be read
via two common wires. With the MLX90614xBx this results in 254 object temperatures measured remotely and
an additional 127 ambient temperatures which are also available. Current source pull-ups may be preferred with
higher capacitive loading on the bus (C3 and C4 represent the lines’ parasitic), while simple resistive pull-ups
provide the obvious low cost advantage.