DPS368 : Pin Diagram, Circuit & Its Applications

The equipment and devices designed today are very sensitive to external environmental conditions. While operating any device in the certain climatic or geographical condition, for the proper working of devices, it becomes crucial to consider certain physical factors such as Humidity present in the surrounding air, temperature, pressure, altitude, airflow conditions, etc… So, the sensors that can measure these quantities are necessary. Along with measuring the quantities, for ease of usage, those sensors should be lightweight, small enough to carry around, robust to damage caused by water or humidity. One of such sensors that can measure both temperature and pressure and meet all these requirements is DPS368 – Barometric pressure sensor.

What is DPS368?

DPS368 is a high precision, digital barometric pressure sensor. This sensor can measure both temperature and pressure. This sensor is robust to water, dust, and humidity. This sensor is of very small size and is suitable for application in smartphones. This sensor has both SPI and I2C interfaces to access the data. Data registers are also provided on-chip.

This sensor is launched by Infineon technologies. It has quick feedback and fast read-out speed. This sensor has low power consumption requirements and is preferred for battery-powered applications. Internal FIFO memory highly contributes to the power saving at the system level.

Block Diagram of DPS368

DPS368-Block-Diagram
DPS368-Block-Diagram

DPS368 contains a temperature sensor and a capacitive pressure sensor. This sensor measures both the barometric pressure and temperature. An ADC is present on the chip to convert the analog values given by the sensor into digital values.

The chip is also integrated with a digital signal processing unit, a memory unit, and a digital interface unit. The digital signal processing unit takes up the task of converting the pressure and temperature values into 24- bit values. There are two separate pins provided to supply voltage to analog and digital blocks separately.

Circuit Diagram

DPS368-Circuit-Diagram-with-I2C-Serial-Interface
DPS368-Circuit-Diagram-with-I2C-Serial-Interface

There are three modes of operation for DPS368 – Standby mode, Command mode, and Background mode. Standby mode is the default mode attained by the sensor when power on or reset. In this mode, no measurements are performed.

In command mode, according to the precision set, either one pressure measurement or one temperature measurement is made and value is stored in the data register. DPS368 returns to standby mode after this measurement.

In background mode, both temperature and/or pressure measurements are made continuously and values are stored in memory. Up to 32 measurements can be stored in the FIFO.

While using for applications VDD and VDDIO are connected to 1.8V supply and to reduce the VDD ripple below 50mVpp suitable decoupling capacitor is added. To reduce the effect of air pressure, IIR filtering is used.

Pin Diagram

DPS368-Pin-Diagram
DPS368-Pin-Diagram

DPS368 is a waterproof sensor. This is available as an 8-Pin LGA package. This sensor is of small size with dimensions 2.0×2.5×1.1 mm. As DPS368 has SPI and I2C interfaces, pins have a different function for different interfaces. Pin description of DPS368 is given below.

  • Pin 1 – GND- is the ground pin. This pin is connected to ground for both the interfaces.
  • Pin-2- CSB – is the Active low Chip Select pin. It is used as a chip select pin when SPI-3 wire, SPI-4 wire, and SPI-3 wire with the interrupt is used. This pin is not used and left open when the I2C interface is used.
  • Pin-3- SDI- is the serial data IN/OUT pin. This pin is used for a serial data IN/OUT for SPI- 3 wire, SPI-3 wire with interrupt, I2C, and I2C with interrupt interfaces. For SPI-4 wire it is used as only serial data IN.
  • Pin-4- SCK – is the serial clock pin. This pin is used as a serial clock for all type of interfaces.
  • Pin-5- SDO- is the serial data output pin. This pin is not used for the SPI-3 wire interface. This pin is used for interrupt in SPI-3 wire Interrupt interface and as serial data out for SPI-4 wire interface. I2C interface uses this pin to set the least significant bit of the device address whereas I2C with interrupt interface uses it for both to set the least significant bit of device address and Interrupt.
  • Pin-6- VDDIO- is the digital supply voltage pin. This pin is used as a digital supply voltage pin for the digital blocks and  Input-Output interfaces.
  • Pin-7-GND-is the ground pin. This pin is connected to the ground during all the interfaces.
  • Pin-8- VDD- is the supply voltage pin. This pin is used to supply voltage to the analog blocks.

Specifications

DPS368 is a Barometric Air pressure sensor. It is a digital sensor. Some of the specifications of this sensor are as follows-

  • The range of supply voltage required by this senor is from 1.2V to 3.6V.
  • During the measurement of different factors, this sensor consumes a different amount of current.
  • This sensor consumes 1.7μA  when used to measure pressure.
  • The operating pressure range of this sensor is from 300 – 1200hPa.
  • When in high precision mode, this sensor can measure pressure with a precision ±0.002 hPa.
  • This sensor can operate in the temperature range of -40° to 85°C.
  • It consumes 1.5μA of current for measuring temperature.
  • Temperature accuracy of this sensor is ±0.5°C.
  • Pressure temperature sensitivity of this sensor is 0.5 Pa/K.
  • Relative accuracy of this sensor is ±0.06 hPa and absolute accuracy is ±1 hPa.
  • DPS368 takes a typical 27.6 ms to measure when operating in standard mode and 3.6 ms when operating in low precision mode.
  • DPS368 consumes 0.5 μA when in standby mode.
  • This sensor has three operating modes – Command or manual mode, Background or automatic mode, and Standby mode.
  • DPS368 has I2C and SPI interfaces with optional interrupts.
  • DPS368 uses capacitive sensing element for measuring pressure.
  • Each unit is calibrated and calibration coefficients are stored in the memory.
  • DPS368 has a FIFO memory that can store up to 32 measurements of pressure and temperature.
  • The internal signal processor converts the analog signal values into 24-bit digital values.
  • DPS368 can withstand water when placed at 50m underwater for 1 hour.
  • This senor is robust to external dust and humidity.
  • DPS368  consumes less power and is very small in size that it can save up to 80 percent of space on the devices.
  • DPS368 can measure temperature and pressure precisely even at high altitudes, Airflow and for Body movements.
  • Capacitive sensing elements helps this sensor to give correct measurements even when there is temperature change.

Applications of DPS368

DPS368 is highly preferred for Mobile applications due to its small size. Some of its applications are listed below-

  • DPS368 is used as an active navigation and tracking system.
  • This sensor is used in mobile phones and wearable devices.
  • In the home appliances, this sensor is used as an Airflow control system.
  • DPS368 is used in drones for flight stability.
  • In medical devices such as smart inhalers, DPS368 is used.
  • DPS368 is used in smartwatches to measure the fitness, for step counting and also for fall detection.
  • DPS368 is used in HVAC
  • This sensor is also used for water level detection and Intruder detection.
  • For height control in drones, DPS368 is used.

The different circuit layout is used while using different interfaces. Information about them, as well as other electrical characteristics of DPS368, can be found in the datasheet. DPS368 is operated in which mode while applied for Indoor navigation?



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