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Motorola Sensor Device Data
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Glossary of Terms
(continued)
Input Impedance (Resistance)
The impedance (resistance) measured between the positive and negative (ground) input terminals
at a specified frequency with the output terminals open. For Motorola X-ducer, this is a resistance
measurement only.
Ion Implantation
A process whereby impurity ions are accelerated to a specific energy level and impinged upon the
silicon wafer. The energy evel determines the depth to which the mpurity ons penetrate the silicon.
Impingement time determines the impurity concentration. Thus, it is possible to independently
control these parameters, and buried piezoresistors are easily produced. Ion implantation is
increasingly used throughout the semiconductor industry to provide a variety of products with
improved performance over those produced by diffusion.
Laser Trimming (Automated)
A method for adjusting the value of thin film resistors using a computer-controlled laser system.
Leakage Rate
The rate at which a fluid is permitted or determined to leak through a seal. The type of fluid, the
differential pressure across the seal, the direction of leakage, and the location of the seal must be
specified.
Linearity Error
The maximum deviation of the output from a straight line relationship with pressure over the
operating pressure range, the type of straight line relationship (end point, least square
approximation, etc.) should be specified.
Load Impedance
The impedance presented to the output terminals of a sensor by the associated external circuitry.
Null
The condition when the pressure on each side of the sensing diaphragm is equal.
Null Offset
The electrical output present, when the pressure sensor is at null.
Null Temperature Shift
The change in null output value due to a change in temperature.
Null Output
See ZERO PRESSURE OFFSET
Offset
See ZERO PRESSURE OFFSET
Operating Pressure Range
The range of pressures between minimum and maximum pressures at which the output will meet
the specified operating characteristics.
Operating Temperature Range
The range of temperature between minimum and maximum temperature at which the output will
meet the specified operating characteristics.
Output Impedance
The impedance measured between the positive and negative (ground) output terminals at a speci-
fied frequency with the input open.
Overpressure
The maximum specified pressure which may be applied to the sensing element of a sensor without
causing a permanent change in the output characteristics.
Piezoresistance
A resistive element that changes resistance relative to the applied stress it experiences (e.g., strain
gauge).
Pressure Error
The maximum difference between the true pressure and the pressure inferred from the output for
any pressure in the operating pressure range.
Pressure Hysteresis
The difference in the output at any given pressure in the operating pressure range when this
pressure is approached from the minimum operating pressure and when approached from the
maximum operating pressure at room temperature.
Pressure Range — also see
Operating Pressure Range
The pressure limits over which the pressure sensor is calibrated or specified.
Pressure Sensor
A device that converts an input pressure into an electrical output.
Proof Pressure
See OVERPRESSURE
Ratiometric
Ratiometricity refers to the ability of the transducer to maintain a constant sensitivity, at a constant
pressure, over a range of supply voltage values.
Ratiometric
(Ratiometricity Error)
At a given supply voltage, sensor output is a proportion of that supply voltage. Ratiometricity error
is the change in this proportion resulting from any change to the supply voltage. Usually expressed
as a percent of full scale output.
F
Freescale Semiconductor, Inc.
n
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