MLX90323
4 – 20 mA Loop Sensor Interface
with Signal Conditioning and EEPROM
Features and Benefits
Application Examples
ꢀ Programmable Sensor Interface IC with 4 to
20 mA current loop output
ꢀ Power supply from 6 to 35VDC
ꢀ Industrial pressure transducers.
ꢀ Strain gauges, accelerometers, position
sensors, etc.
ꢀ External or internal temperature sensor for
compensating temperature errors
ꢀ Any bridge type sensor with current loop
output.
Ordering code
Product Code Temperature Code
Package Code Option Code
Packing Form Code
MLX90323
MLX90323
K
K
DF
DF
AAA-000
AAA-000
TU
RE
Legend:
Temperature Code: K for Temperature Range -40°C to +125°C
Package Code:
Packing Form:
DF for SOIC300Mil
RE for Reel, TU for Tube
Ordering example:
MLX90323KDF-AAA-000-TU
1 Functional Diagram
2 General Description
The IC converts small changes of output voltage
of full Wheatstone resistive bridge (caused by
mechanical stimulus such as pressure, force,
torque, light or magnetic field) to large changes of
the IC output current.
FET
VDD1
OFC
FLT
VDD
Supply Regulator
3.5V
DAC_Offset
It removes parasitic DC level (Offset) from the
output bridge voltage and amplifies this signal
certain times (Gain). Offset and Gain are
temperature dependant, so the IC allows
temperature compensation of bridge parasitic DC
shift and sensitivity. Temperature can be
measured either by internal or external (resistor)
temperature sensor. The values of Offset and
Gain and their temperature dependency are
gotten during the calibration process and are
stored in the EEPROM..
OPA
0V
2-bit
CSGN
VBP
VBN
x 35
x2
GAIN
1.24kOhm
0.97V/V
0.48V/V
INV
Hardware Gain = 70
Coarse Offset
GAIN
CMO
CMN
TMP
Fine Gain DAC
IO1
IO2
Micro-
Processor
COMS
3.5V
External
Temp Sensor
ADC
Internal
Temp Sensor
Temp Amp Gain
GNTP [1:0]
0V
GND
TSTB
The IC has industry standard 4 – 20 mA current
loop output interface and takes power directly from
2-wire signal line. The MLX90323 works properly
over wide voltage range (from 6 to 35 V) at the
signal line.
3901090323
Rev 003
Page 1 of 25
Data Sheet
Feb/12