MAX1455 Datasheet, PDF (22/25 Pages) Maxim Integrated Products – Low-Cost Automotive Sensor Signal Conditioner

Low-Cost Automotive Sensor Signal
Conditioner
RAW SENSOR OUTPUT
(T_A = +25°C)
80
60
40
20
0
0
20
40
60
80
100
PRESSURE (kps)
COMPENSATED TRANSDUCER ERROR
0.15
FSO OFFSET
0.10
0.05
0
-0.05
-0.10
-0.15
-50
0
50
100
150
TEMPERATURE (°C)
UNCOMPENSATED SENSOR
TEMPERATURE ERROR
30
FSO OFFSET
20
10
0
-10
-20
-50
0
50
100
150
TEMPERATURE (°C)
COMPENSATED TRANSDUCER
(T_A = +25°C)
5
4
3
2
1
0
0
20
40
60
80
100
PRESSURE (kps)
Figure 8. Comparison of an Uncalibrated Sensor and a Calibrated Transducer
• Download correction coefficients to EEPROM.
• Perform a final test.
Sensor Calibration and
Compensation Example
The MAX1455 temperature compensation design cor-
rects both sensor and IC temperature errors. This
enables the MAX1455 to provide temperature compen-
sation approaching the inherent repeatability of the
sensor. An example of the MAX1455’s capabilities is
shown in Figure 8. Table 16 lists the effects of compen-
sation.
A MAX1455 and a repeatable piezoresistive sensor with
an initial offset of 16.4mV and a span of 55.8mV were
converted into a compensated transducer with an offset
of 0.5000V and a span of 4.0000V. Nonlinear sensor
offset and FSO temperature errors, which were on the
order of 20% to 30% FSO, were reduced to under
±0.1% FSO. Figure 8 shows the output of the uncom-
pensated sensor and the output of the compensated
transducer. Six temperature points were used to obtain
this result.
MAX1455 Evaluation Kit
To expedite the development of MAX1455-based
transducers and test systems, Maxim has produced the
MAX1455 evaluation kit (EV kit). First-time users of the
MAX1455 are strongly encouraged to use this kit.
The EV kit is designed to facilitate manual programming
of the MAX1455 with a sensor. It includes the following:
1) Evaluation board with or without a silicon pressure
sensor, ready for customer evaluation.
2) Design/applications manual. This manual was
developed for test engineers familiar with data
acquisition of sensor data and provides sensor
compensation algorithms and test procedures.
3) MAX1455 communication software, which enables
programming of the MAX1455 from a computer key-
board (IBM compatible), one module at a time.
4) Interface adapter, which allows the connection of
the evaluation board to a PC serial port.
Chip Information
TRANSISTOR COUNT: 62,242
PROCESS: CMOS
SUBSTRATE CONNECTED TO: V_SS
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