Absolute Maximum Ratings
Absolute maximum ratings are the extreme conditions, that a product can withstand without taking damage. Stresses above these ratings may cause permanent damage. Exposure to absolute maximum conditions for extended periods may degrade product reliability.
A (voltage) amplifier is a device which increases the amplitude
of a voltage input signal by a certain gain, defined as the ratio of the output voltage signal to the input voltage signal. Ideally an amplifier will increase the input voltage signal's amplitude without changing any other aspects of the input signal.
The amplitude of a signal is defined as the deviation of a time varying signal or oscillation from its offset
In electrical circuits analog voltage or current signals are signals of continuous in amplitude
Atmospheric pressure is the ambient air pressure resulting from the weight of air in earth' atmosphere in reference to perfect vacuum
. Atmospheric pressure is sometimes called barometric pressure.
For an analog amplifier
or sensor the bandwidth specifies the device's frequency behaviour. The bandwidth is the difference between the minimum and the maximum frequency, at which a signal can be processed without a decrease.
Best Fit Straight Line
The best fit straight line is the straight line fitted through a set of points, which minimizes the sum over the square of each points' deviation from the straight line ('least squares' method).
The binary system is a number system with base 2. All numbers in the binary system are represented as a string of ones and zeros. A one is represented by a non-zero voltage (high-level) and a zero by ≈ 0 V (low-level). In 4 bit binary the numbers 0, 1, 2, 3 up to 15 would be represented by 0000, 0001, 0010, 0011 .. 1111 respectively.
Typically the total bridge resistance is the impedance of an uncompensated, unamplified Wheatstone bridge.
Burst pressure is defined as the maximum pressure, which may be applied to one pressure port relative to the other port (or while only one pressure port is connected) without causing leaks in the sensor. The sensor should not be expected to function after exposure to any pressure beyond the burst pressure.
The calibration of a sensor is the comparison with a standard and the adjustment of the sensor's output signal to bring it into alignment with the standard (according to the sensor's specifications).
A capacitance-to-voltage converter is used to convert the capacitance of a connected capacitor or capacitive measurement head into a voltage output signal.
Clipping limits are the maximum and minimum output signal limits, where the product will produce an output signal under normal operating conditions.
Common-Mode Rejection Ratio (CMRR)
The common-mode rejection ratio of a differential amplifier
is the rejection of unwanted input signals common to both inputs relative to the wanted difference signal. Typically the CMRR is expressed in dB.
During compensation the unwanted effects in a sensor's behaviour are minimized by signal-conditioning. Typically for pressure sensors the non-linearity
and temperature effects are compensated to minimize the deviation from the ideal transfer function
The corner frequency is a boundary in a system's frequency response at which the signal amplitude
is decreased below a certain level. Often it is defined as the frequency where signal amplitude is reduced by 3 dB.
Current consumption is the maximum current an electrical circuit will draw during operation, when no load is connected.
Current Output - Three-Wire Operation
A device with current output can be used to transmit signals over long distances. For a device with current output in three-wire operation three wires have to be used for the device's connection: one to power the system, one for the connection to ground and one for the current output. In contrast to the current output in two-wire operation the current output in three-wire operation does not depend on the device's current consumption
. Therefore it is possible to generate output currents down to 0 mA.
A device with current-loop output has a two-wire interface and a current output signal (e.g. 4 .. 20 mA). The device is connected to the power source using two wires forming the current-loop. Powered by the current-loop the device controls the current flowing in the loop. The current in the loop is the device's output signal.
The dead volume is the open volume inside a product which is occupied by fluids or gases begin sensed.
Under normal operating conditions the product will produce outputs following the transfer function. Detection of a signal outside these limits indicates a fault condition which allows the detection of a sensor failure.
A die is an unpackaged silicon chip.
Differential pressure is the difference between the pressure applied at two pressure ports.
A digital signal has a discrete range of values in an electrical circuit. It is not continuous in time and amplitude
. Typically the logic 1 corresponds to the high level voltage in an electrical circuit and the logic 0 corresponds to a low level voltage.
The drift of a sensor is a time dependent change of the sensor's output signal while the applied measuring and ambient conditions are constant.
Dual In-Line Package (DIP)
A Dual In-Line Package is a rectangular sensor and IC
package with two parallel rows of pins usually used for through-hole assembly. Mostly DIPs are referred to as DIPn, where n is the number of the package's pins.
Gage Pressure Sensor
Gage pressure sensors are sensors used to measure the difference between applied pressure and local ambient (atmospheric
) pressure. Typically the minimum pressure (pmin
) is set to ambient pressure.
For an amplifier
the gain-bandwidth product is the product of the amplifier's bandwidth
and the adjusted gain, at which the bandwidth is measured. For an operational amplifier
the gain-bandwidth product is nearly independent of the gain, so that it is equal to the unity-gain bandwidth of the amplifier.
The hexadecimal system is a number system with the base 16. All numbers in the hexadecimal system are represented as a string consisting of 0 .. 9 and A .. F for the numbers 0 to 15. 4 bit binary numbers
can be represented using only one digit in hexadecimal numbers. In the hexadecimal system the numbers 0, 5, 10 and 15 would be represented by 0, 5, A and F respectively.
Hysteresis is the output signal's dependence not only on the current input signal but also on the input signal's change direction and history. For pressure sensors temperature and pressure hysteresis are important hysteresis effects influencing the sensor's total accuracy
. (see pressure
and thermal hysteresis
I2C is a multi-master, multi-slave serial computer bus invented by Philips Semiconductors. The communication uses two bidirectional bus lines: a serial data line (SDA) and a serial clock line (SCL) which are pulled up using resistors. Typical voltage high levels are 5 V or 3.3 V and data rates up to 3.4 Mbit/s are allowed. Typically an I2C bus works at 100 up to 400 Hz.
Ideal Transfer Function
The ideal transfer function is the desired functional relationship between the input and the output signal of a system. For pressure sensors the ideal transfer function is a linear relationship between the applied pressure (difference) signal and the output signal with a slope equal to the Full Span Output
over the desired pressure range
The electrical impedance measured across the input terminals of the product (as presented to the excitation source with the output terminals open circuited.
Instrumentation Amplifier (IA)
An instrumentation amplifier is a type of amplifier
, that amplifies the difference between the input voltage signals while rejecting input signals that are common to both inputs. An instrumentation amplifier is especially suitable for use in measurement and test equipment, where high accuracy
is required. It has a differential input with very high input impedance
, a single-ended output with very low output impedance
and internal feedback resistors isolated from the inputs. Further characteristics are a very high common-mode rejection ratio
, very low DC offset
, low drift and low noise.
Integrated Circuit (IC)
An integrated circuit is an electronic circuit containing all the elements of the specific circuit on a single semiconductor substrate.
Line Regulation is the capability to maintain a constant output voltage level despite changes in the input voltage level.
Linearity describes the behaviour of an electrical circuit, when the transfer function is represented by a straight line. Deviations from the ideal behaviour are specified by the non-linearity. See Non-Linearity
Load Regulation is the capability to maintain a constant output voltage or current despite changes in the connected load.
Long Term Stability
The long term stability is the maximum deviation of a system's output over time while the system is measured under the same conditions. Typically a sensor's long term stability is given in %FSO per year.
Our OEM sensors are parts which are designed for the installation in packages or systems and which can't be used as stand-alone product.
The offset is a constant part of a system's output signal and is independent of changes in the system's input.
The open-loop gain of an amplifier
is the gain obtained, when no feedback is used in the circuit. Typically the open loop gain of an operational amplifier
is > 105
and decreases with increasing input signal frequency.
Operating Temperature Range
The operating temperature range is the ambient temperature range over which the product can be used (and powered).
Operational Amplifier (OP)
An operational amplifier is a DC coupled, high gain, electronic voltage amplifier
with differential input and usually single-ended output. It has a very high open-loop gain
. Typically OPs are used in a closed loop with negative feedback, as well as resistors to adjust the circuits overall gain.
The electrical impedance measured across two differential output terminals of the product or between the output terminal and GND (as represented to an external circuit).
The smallest meaningful change in output signal, which can be related to an input signal change and distinguished from noise. The output resolution is usually expressed in %FSO.
A piezoresistive element is a resistive element that changes its resistance relative to the applied mechanical stress (e.g. applied pressure).
For a pressure sensor the position sensitivity is defined as the maximum change in the product's output due to a change in position or orientation relative to the Earth's gravitational field, when no pressure difference is applied at the membrane of the sensing element
(zero pressure offset
Power Supply Rejection Ratio (PSRR)
The power supply rejection ratio of an electrical system is defined as the ratio of the supply voltage change to the output voltage change it produces. The PSRR is usually given in dB.
Pressure hysteresis is the maximum deviation of a pressure sensor's output value at any pressure within the specified range
when the pressure is cycled to and from the minimum or maximum rated pressure.
Pressure Sensing Element
The pressure sensing element is the part of a pressure sensor, that converts the applied physical pressure into an electrical signal using a flexible membrane structure.
Our pressure transmitters are ready-to-use pressure sensors. They are already housed in a robust package with pressure ports and a plug or cable for electrical connection.
Ratiometric Voltage Output
The ratiometric voltage output is a kind of system's voltage output, for which the output voltage is proportional to the system's supply voltage (for any input signal within the specified range). The typical range of a ratiometric voltage output is 0.5 .. 4.5 V.
systems the output voltage is a proportion of the supply voltage, while keeping the input signal constant. The ratiometricity error is given by the maximum deviation of the output voltage signal from the ideal ratiometric behaviour due to any change of the supply voltage at any input signal within the specified range. Usually the value is specified in in ppm (normalized to the supply voltage), sometimes in %FSO.
A pressure sensor's repeatability is the output's maximum deviation at any pressure in the specified pressure range
, when the same pressure is applied consecutively, under the same operating conditions with pressure approaching from the same direction within ten pressure cycles.
The response time is the time taken by a sensor to respond to an input signal step by changing the output value from its previous stable state to a new steady state. Usually the response time is defined as the time it takes for the sensor to traverse between 10% and 90% of its final value.
Restriction of Hazardous Substances Directive (RoHS)
RoHS restricts the use of lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls (PBB) and polybrominated diphenyl ether (PBDE) in the manufacture of various types of electronic and electrical equipment. The maximum permitted concentrations in non-exempt products are 0.1 % or 1000 ppm (except for cadmium, which is limited to 0.01 % or 100 ppm) by weight.
Self heating is an electrical component's internal heating as a result of power dissipation.
A pressure sensor's sensitivity is the ratio of output signal change to the corresponding input pressure change. Sensitivity is given by the ratio of full scale span to the specified difference of maximum and minimum pressure. Sometimes sensitivity is normalized using the supply voltage.
Shrink Small Outline Package (SSOP)
Shrink small outline packages are small leaded IC
packages used to mount integrated circuits on PCB boards in surface-mount technology. SSOP packages have a higher pin density than SO packages.
The maximum current an amplified circuit can accept ('sink') on its output pin and still remain within the specified performance limits.
In electronics slew rate is defined as the output voltage's maximum change rate per second. If the slew rate is too slow it can lead to non-linear effects in an amplifier's
Small Outline Package (SOP)
Small outline packages are small leaded IC
packages used to mount integrated circuits on PCB boards in surface-mount technology.
The maximum current an amplified circuit can supply ('source') on its output pin and still remain within the specified performance limits.
Storage Temperature Range
Storage temperature is the temperature range to which the product may safely be exposed without excitation or pressure applied. Under these conditions the product will remain in specification after excursion to any temperatures within this range. Exposure to temperatures outside this range may cause permanent damage to the product.
Supply Voltage Range
The supply voltage range is the specified range of voltage excitation which can be supplied to the product.
A temperature compensation is the correction of unwanted thermal effects on a sensor or electrical system by signal-conditioning. For silicon pressure sensors a temperature compensation is essential to achieve an output nearly independent of temperature. See compensated temperature range
Thermal hysteresis is the maximum deviation of the output value at any temperature within the specified range when the temperature is cycled to and from the minimum or maximum specified temperature. Typically for sensors the value is given in %FSO.
A voltage reference is an electronic circuit, which produces a high stable, constant output voltage (sometimes adjustable). Variations of the component's temperature, the supply voltage or the applied load within the specified ranges have no influence on the output voltage.