Features * Commercial grade * DIP version for high volume production * Gauge or absolute pressure * Resistive bridge technology * Voltage or current excitation Applications * Medical applications * Blood pressure * Portable Gauges * Process control * HVAC controls
The Smart Pressure Device SPD series of pressure sensors are silicon based and encapsulated in modified plastic Dual In Line packages, to accommodate six pins for through-board printed circuit mounting. The sensors come in two distinct types: Gauge and absolute. The gauge type merely measures the pressure with respect to the atmospheric pressure. The absolute type contains a reference vacuum chamber, which is formed on the die during manufacturing. The output voltages of both types are proportional to the pressure that is measured. Various pressure ranges are available. On request, other ranges and encapsulations can be supplied. Please contact our sales department for more information. Because of it's bridge resistance value, the SPD pressure sensor is especially suited for use in combination with the Universal Transducer Interface (UTI03), which gives an easy and very accurate interface to a digital environment.
-1 SMARTEC BV, Delpratsingel 4811 AP Breda, The Netherlands WWW.SMARTEC.NL Tel: 76 5205353
Excitation Voltage Excitation Current Offset Temp Coeff Span Temp Coeff Offset Temp Coeff Resistance Linearity Hysteresis Repeatability ) Response time (10-90%) Bridge resistance Pressure overload Operating temperature Storage temperature
) measured after 1,000 temp. cycles 70 °C, 10 pressure cycles (10-90% FS)
The available range of SPD series pressure sensors allows for a wide range of applications. In order to get good results, it is very important to fully understand the meaning of the various specifications and their effects on accuracy, especially the ones that deal with temperature coefficients. (Silicon resistors are very temperature dependent).
-2 SMARTEC BV, Delpratsingel 4811 AP Breda, The Netherlands WWW.SMARTEC.NL Tel: 76 5205353
Excitation voltage The excitation of the sensor can AC or DC. Specifications are given with a DC excitation 5V. In order to avoid electrical breakdown it is advised not to exceed the maximum values given. Offset The offset value is the electrical output voltage (imbalance) of the pressure sensor when zero pressure is applied. The offset value for the absolute type is determined by extrapolating the measured values at two different pressures (atmospheric air and 0.05 Bar). The pressure in reference chamber is about 25 mTorr (3.33 Pa). Temperature coefficients Silicon resistors are very temperature dependent. The overall drift of the resistors is not of interest to most users (The bridge resistors are located on the same die). The temperature coefficients of the offset and span, however, are very important. All the temperature coefficients are given in percentage of full-scale range (FS) and over a temperature range of 100 °C. The maximum value of the temperature coefficient of the span is minus 27%, which means that worst case the span becomes 27% smaller over the full temperature range of 100 °C. The offset will vary no more than ±7% of the span over the same temperature range. Calculation example (please refer to the parameter table above) Suppose the use of a pressure sensor of type SPD 015G over a temperature range of 100 °C. The typical full scale span is 140 mV. The offset (at a fixed temperature) will be between -50 and +50 mV. Offset When the static part of the offset has been nulled, the offset can still vary mV 9.8 mV), over the temperature range of 100°C. Span The typical full-scale span 140 mV and the typical temperature coefficient of the span equals 22 %FS/100 °C. Typically, you would therefore have a span, which varies between 140 mV and (140 mV minus 22%), over the full temperature range of 100 °C.
-3 SMARTEC BV, Delpratsingel 4811 AP Breda, The Netherlands WWW.SMARTEC.NL Tel: 76 5205353