US1881ESE Melexis Inc, US1881ESE Datasheet - Page 43

• Manufacturer Part Number: US1881ESE
• Description: IC LATCH CMOS MP TSOT23-3
• Manufacturer: Melexis Inc
• Type: Bipolar Latchr

Specifications of US1881ESE

• Sensing Range: 9.5mT Trip, -9.5mT Release
• Voltage - Supply: 3.5 V ~ 24 V
• Current - Supply: 5mA
• Current - Output (max): 50mA
• Output Type: Digital, Open Drain
• Operating Temperature: -40°C ~ 85°C
• Package / Case: TSOT-23-3, TSOT-3
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Other names: US1881ESETR

The Programmable Sensor Interface
A microcontroller sensor interface provides signal conditioning for a sensor element of any kind. Some types of
sensor elements that can be used are pressure sensors, strain gauges, load cells, thermistors, and potentiometers
(position sensing).
The MLX90308 sensor interface provides control over the offset, gain (or sensitivity), linearity and temperature
compensation of the sensor’s signal using a microcontroller.
In the past, such conditioning was done through discrete circuits. Such circuits required costly and unreliable
trimming methods, not to mention component count on the PC board. Because the MLX90308 is a microcon-
troller, calibration is done digitally through a standard PC. The MLX90308 contains an 8-bit RISC core micro-
controler, analog signal path, supply regulator, and EEPROM for storing compensation coefficients.
Figure 29 illustrates a fundamental application of the MLX90308 and a bridge type pressure sensor element. In
this application, the 90308 uses an external FET as a pass transistor to regulate the voltage to the sensor and the
analog portion of the IC. This is known as Absolute Voltage Mode, where voltage to the sensor and analog cir-
cuit is regulated, independent of the supply voltage. The 90308 can be operated in Ratiometric Voltage Mode,
where the output (VMO) is tied to an A/Dconverter sharing the same Supply and GND reference. A third wiring
Figure 29 - Oil Pressure Gauge
Pressure
Sensor
1
2
3
4
5
6
7
8
TSTB
VBN
VBP
TMP
FLT
OFC
IO1
IO2
COMS
VDD1
GND
CMN
CMO
VMO
VDD
FET
16
15
14
13
12
11
10
9
for Regulation
External FET
G
Communications
D
S
Signal Out
Communications
GND
Signal Out
V+
GND
V+
Pressure
(psi)
Oil