MAX1478 Datasheet, PDF (1/20 Pages) Maxim Integrated Products – 1% Accurate, Digitally Trimmed,Rail-to-Rail Sensor Signal Conditioner

19-1538; Rev 0; 9/99
EVAALVUAAILTAIOBNLEKIT
1% Accurate, Digitally Trimmed,
Rail-to-Rail Sensor Signal Conditioner
General Description
The MAX1478 highly integrated, analog sensor signal
processor is optimized for piezoresistive sensor calibra-
tion and compensation without any external compo-
nents. It includes a programmable current source for
sensor excitation, a 3-bit programmable-gain amplifier
(PGA), a 128-bit internal EEPROM, and four 12-bit digi-
tal-to-analog converters (DACs). Achieving a total error
factor within 1% of the sensor’s repeatability errors, the
MAX1478 compensates offset, offset temperature coeffi-
cient, full-span output (FSO), FSO temperature coeffi-
cient (FSO TC), and FSO nonlinearity of silicon
piezoresistive sensors.
The MAX1478 calibrates and compensates first-order
temperature errors by adjusting the offset and span of
the input signal via DACs, thereby eliminating the quan-
tization noise associated with digital signal path solu-
tions. Built-in testability features on the MAX1478 result
in the integration of three traditional sensor-manufactur-
ing operations into one automated process:
• Pretest: Data acquisition of sensor performance
under the control of a host test computer.
• Calibration and compensation: Computation and
storage (in an internal EEPROM) of calibration and
compensation coefficients computed by the test
computer and downloaded to the MAX1478.
• Final test operation: Verification of transducer cali-
bration and compensation without removal from the
pretest socket.
Although optimized for use with piezoresistive sensors,
the MAX1478 may also be used with other resistive
sensors (i.e., accelerometers and strain gauges) with
some additional external components.
______________________Customization
For high-volume applications, Maxim can customize the
MAX1478 for unique requirements. With a dedicated
cell library consisting of more than 90 sensor-specific
functional blocks, Maxim can quickly provide cus-
tomized MAX1478 solutions.
________________________Applications
Piezoresistive Pressure and Acceleration
Transducers and Transmitters
Manifold Absolute Pressure (MAP) Sensors
Automotive Systems
Hydraulic Systems
Industrial Pressure Sensors
Strain-Gauge Sensors
Industrial Temperature Sensors
Features
o Medium Accuracy (±1%), Single-Chip Sensor
Signal Conditioning
o Rail-to-Rail^® Output
o Sensor Errors Trimmed Using Correction
Coefficients Stored in Internal EEPROM—
Eliminates Laser Trimming and Potentiometers
o Compensates Offset, Offset TC, FSO, FSO TC,
and FSO Linearity
o Programmable Current Source (0.1mA to 2.0mA)
for Sensor Excitation
o Fast Signal-Path Settling Time (<1ms)
o +5V Single Supply
o Accepts Sensor Outputs from +10mV/V to
+40mV/V
o Fully Analog Signal Path
Pilot Production System
To simplify your pressure sensor design, Maxim has
developed a fully automated pilot production system
that will smooth the difficult transition from prototype to
production. Details appear at the end of this data sheet.
Ordering Information
PART
TEMP. RANGE PIN-PACKAGE
MAX1478C/D
0°C to +70°C
Dice*
MAX1478AAE
-40°C to +125°C 16 SSOP
*Dice are tested at T_A = +25°C, DC parameters only.
Functional Diagram appears at end of data sheet.
Pin Configuration
TOP VIEW
SCLK 1
CS 2
I.C. 3
TEMP 4
FSOTC 5
DIO 6
WE 7
V_SS 8
MAX1478
SSOP
16 I.C.
15 V_DD
14 INM
13 BDRIVE
12 INP
11 I.C.
10 OUT
9 ISRC
Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.
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