EVB90615 Datasheet, PDF (22/30 Pages) Melexis Microelectronic Systems – Infra Red Thermometer

MLX90615
Infra Red Thermometer
11 Applications Information
11.1 Use of the MLX90615 thermometer in SMBus configuration
+3.3V
1 MLX90615
SD A
U1
/P W M
2 ^Vdd
Vss ⁴
C1
SCL
3
0.1uF
R1 R2
SMBus
U2
Vdd
SDA
SCL
GND
MCU
Figure 18: Connection of MLX90615 to SMBus.
MLX90615 has diode clamps SDA/SCL to Vdd so it is necessary to provide MLX90615 with power in order
not to load the SMBus lines.
11.2 Use of multiple MLX90615s in SMBus configuration
+3.3V
1 MLX90615
SDA
U2
/P W M
2 ^Vdd
Vss ⁴
C1
SCL
3
0.1uF
I1
Ipu1
I2
Ipu2
R1 R2
SMBus
Current source or resistor
pull-ups of the bus
U1
Vdd
SDA
SCL
GND
MCU
1 MLX90615
SDA
U3
/P W M
2 ^Vdd
Vss ⁴
C2
SCL
3
0.1uF
C3
Cbus1
Cbus2
C4
SDA SCL
Figure 19: Use of multiple MLX90615 devices in SMBus network
The MLX90615 supports a 7-bit slave address in EEPROM, thus allowing up to 127 devices to be read via
two common wires. Current source pull-ups may be preferred with higher capacitive loading on the bus (C3
and C4 represent the lines’ parasitics), while simple resistive pull-ups provide the obvious low cost
advantage.
3901090615
Rev 001
Page 22 of 30
Data Sheet
28/Aug/2008