MLX90314
Programmable Sensor Interface
Figure 11. Error Compensation
Table 14. Glossary of Terms
A/D analog to digital conversion
ADC analog to digital converter
ASCII American Standard Code for Information
Interchange
ASIC application specific integrated circuit
CM current mode
Figure 11a. Raw Sensor Output
(measured between VPB and VBN)
CMN current mode negative (supply connection)
CMO current mode output
COMS communication, serial
CR carriage return
170
CSGN coarse gain
CSOF coarse offset
CV current / voltage mode select bit
DAC digital to analog converter
DACFnew filtered DAC value, new
DACFold filtered DAC value, old
DARDIS DAC resistor disable
dB decibel
DOGMO digital mode
EEPROM electrically erasable programmable read only
memory
EOC end of conversion flag bit
ESD electrostatic discharge
ETMI timer interrupt enable
ETPI enable temperature interrupt
FET field effect transistor
FG fixed gain
140oC
25oC
-40oC
0
0%
100%
Pressure
FLT filter pin
GNO gain and offset adjusted digitized signal
GNOF gain, offset
GNTP temperature gain / offset coarse adjustment
HS hardware / software limit
I/O input / output
Figure 11b. Conditioned Sensor
Output
IFIX fixed current output value
IINV input signal invert command bit
ILIM current limit
4
kHz kilohertz, 1000 Hz
LSB least significant bit
mA milliamperes, 0.001 amps
MODSEL mode select
ms millisecond, 0.001 second
MSB most significant bit
MUX multiplexer
mV millivolts, 0.001 Volts
nF nanofarads, 1 X 10-9 farads
OFC offset control
PC personal computer, IBM clone
pF picofarad, 1 X 10-12 farads
PLL phase locked loop
140oC
25oC
-40oC
POR power on reset
RAM random access memory
RISC reduced instruction set computer
ROM read only memory
RS-232 industry std. serial communications protocol
RX receive
1
0%
100%
Pressure
SAR successive approximation register
STC start A/D conversion
Tdiff temperature difference
Text temperature, external
TMI timer Interrupt
Figures 11a and 11b above illustrate the performance
of an unconditioned sensor output and a conditioned
sensor output versus stimulus (pressure) and
temperature. It can be seen that Figure 11a has a
range of only 170 mV (maximum range with a 5V
supply) and has a non-linear response over a 0-100
psi range. The sensitivity of the unconditioned output
will also drift over temperature, as illustrated by the
three slopes. The MLX90314 corrects these errors
and amplifies the output to a more usable voltage
range as shown in Figure 11b.
TMP temperature signal
TPI temperature interrupt
Tref temperature reference
TSTB test mode pin
TX transmit
UART universal asynchronous receiver / transmitter
VBN bridge, positive, input
VBP bridge, negative, input
VDD supply voltage
VM voltage mode
VMGN voltage mode gain
VMO voltage mode output
WCB warn / cold boot
WDC watch dog counter
MLX902xx Name of Sensor Rev Y.X 22/Aug/98
3901090314
Page 25
Page 25
Nov/04
Rev 007
MELEXIS [ Melexis Microelectronic Systems ]
