SDP800/810 Digital
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Datasheet SDP8xx-DigitalDigital Differential Pressure Sensor ■ Excellent repeatability, no drift, no offset ■ Extended feature set - smart averaging ■ Calibrated and temperature compensated Product Summary The SDP800 sensor family is Sensirion's series of digital differential pressure sensors designed for high-volume applications. The sensors measure the pressure of air and non-aggressive gases with superb accuracy and no offset drift. The sensors cover a pressure range of up to ±500 Pa (±2 inch H2O / ±5 mbar) and deliver outstanding accuracy, also at the bottom end of the measuring range. The SDP800 features a digital 2-wire interface, which makes it easy to connect directly to a microprocessor. The outstanding performance of these sensors is based on Sensirion's patented CMOSens® sensor technology, which combines the sensor element, signal processing and digital calibration on a small CMOS chip. The differential pressure is measured by a thermal sensor element using flow-through technology. The well-proven CMOS technology is perfectly suited for high-quality mass production and is the ideal choice for demanding and cost-sensitive OEM applications. Benefits of Sensirion’s CMOSens® Technology ■ High reliability and long-term stability ■ Best signal-to-noise ratio ■ Industry-proven technology with a track record of more than 15 years ■ Designed for mass production ■ High process capability

1. Sensor Performance1.1 Differential Pressure Specification1 Parameter Unless otherwise noted, all sensor specifications are valid at 25°C with VDD = 3.3 V and absolute pressure = 966 mbar. For other pressure ranges contact Sensirion Includes repeatability Total accuracy/repeatability is a sum of zero-point and span accuracy/repeatability. The measured temperature is the temperature of the bulk silicon in the sensor. This temperature value is not only depending on the gas temperature, but also on the sensor's surroundings. Using the signal to measure solely the gas temperature will need...

2. Specifications 2.1 Electrical Specifications 1 For Air and N2. Long term exposure to (high concentrations of) O2 at high temperatures can reduce the product lifetime

3. Pin Assignment The pin assignments of the SDP8xx-Digital can be found in Table 1 Table 1: SDP8xx-Digital pin assignment (bottom view).

4. Measurement Modes The SDP8xx-Digital is a highly versatile differential pressure sensor and is very flexible regarding the measurement speed. This flexibility not only allows for optimizing the sensor's performance to a specific application, but also for adapting the sensor to different use cases. For example, in one use case the sensor is detecting the smallest and quickest changes, whereas at another time the sensor can measure in larger intervals while consuming only little energy. 4.1 Continuous Mode vs Triggered Mode In continuous mode the sensor is measuring at the highest speed...

5. Digital Interface Description The SDP8xx-digital interface is compatible with the I2C protocol. This chapter describes the command set for SDP8xx-digital. For detailed information about the I2C protocol, please check the document "NXP I2C-bus specification and user manual". The I2C address for SDP8xx-digital is 0x25 (b 0100101). The address is followed by a read or write bit. For other I2C addresses contact Sensirion. The commands are 16-bit. Data is read from the sensor in multiples of 16-bit words, each followed by an 8-bit checksum to ensure communication reliability. I2C master...

5.3.1 Start Continuous Measurement The sensor measures both the differential pressure and temperature. Both measurement results can be read out through one single I2C read header. Continuous measurements can be started up in different configurations by a set of commands. When the sensor is in continuous measurement mode, the sensor must be stopped before it can accept another command. The only exception is the soft reset command as described in section 5.3.4. In idle mode the sensor will consume less power, but consider the sleep mode for most effective energy saving.

5.3.3 Triggered Measurement During a triggered measurement the sensor measures both differential pressure and temperature. The measurement starts directly after the command has been sent. The command needs to be repeated with every measurement. After the reset command the sensor will take maximum 2ms to reset. During this time the sensor will not acknowledge its address nor accept commands.

5.3.5 Entering and Exiting Sleep Mode In sleep mode the sensor uses the minimum amount of current. The mode can only be entered from idle mode, i.e. when the sensor is not measuring. This mode is particularly useful for battery operated devices. To minimize the current in this mode, the complexity of the sleep mode circuit has been reduced as much as possible, which is mainly reflected by the way the sensor exits the sleep mode. In sleep mode the sensor cannot be soft reset.

5.4 Checksum Calculation The checksum byte is generated by a CRC algorithm with the following properties: 5.5.2 Differential Pressure The digital calibrated differential pressure signal read from the sensor is a signed integer number (two's complement number). The integer value can be converted to the physical value by dividing it by the scale factor. differential pressure = sensor output ^ scale factor 5.5.3 Temperature The digital calibrated temperature signal read from the sensor is a signed integer number (two's complement number). The integer value can be converted to the physical...

Dimensions SDP80x – Manifold Connection Dimensions SDP81x – Tube Connection Figure 2: SDP81x. All dimensions in mm. www.sensirion.com

Figure 3: Footprint for PCB mounting (top view = sensor side). All dimensions in mm. A: Overall sensor dimensions B: Holes for additional mounting screws (optional) In case the sensor is not mounted on a PCB and is connected with a cable the SDP800 series cap is recommended. Standard wave soldering systems may be used for soldering SDP800 series sensors. Reflow soldering is not feasible and may damage the sensor. The sensor ports must be protected from solder splash and flux during soldering. Figure 4 shows an appropriate temperature profile with maximum temperature values. Entrance to...