mlx90323 Melexis Company, mlx90323 Datasheet - Page 21

• Manufacturer Part Number: mlx90323
• Description: 4 ? 20 Ma Loop Sensor Interface With Signal Conditioning And Eeprom
• Manufacturer: Melexis Company

Customization
Melexis can customize the MLX90323 in both hardware and firmware for unique requirements.
hardware design provides 64 bytes of RAM, 3 kbytes of ROM, and 48 bytes of EEPROM for use by the
firmware.
Special Information
The output of the sensor bridge is amplified via offset and gain amplifiers and then converted to the correct
output signal form in one of the output stages.
The sensitivity and offset of the analog signal chain are defined by numbers passed to the DAC interfaces
from the microcontroller core (GN[9:0] and OF[9:0]). The wide range of bridge offset and gain is
accommodated by means of a 2-bit coarse adjustment DAC in the offset adjustment (CSOF[1:0]), and a
similar one in the gain adjustment (CSGN[2:0]). The signal path can be directed through the processor for
digital processing.
Programming and Setup
The MLX90323 needs to have the compensation coefficients programmed for a particular bridge sensor to
create the sensor system. Programming the EEPROM involves some minimal communications interface
circuitry, Melexis setup software, and a PC. The communications interface circuitry is available in a
development board. This circuitry communicates with the PC via a standard RS-232 serial communications
port.
3901090323
Rev 001
8 Unique Features
9 Application Information
100 nF
5K
COMS
VDD
VBN
TMP
VBP
GND
FET
Page 21 of 24
VDD1
CMO
CMN
FLT
with Signal Conditioning and EEPROM
39 nF
4 – 20 mA Loop Sensor Interface
75 Ohms
24 Ohms
100 nF
MLX90323
stability of the
100 nF
Depends on
current loop
Supply
Ground
Data Sheet
March/08
The