Industry Article

The Need for High-Accuracy Ultra-Low Pressure Sensors

November 23, 2021 by Craig Sanderson, Sager Electronics

Learn about the benefits of board-mounted pressure sensors and the considerations when selecting them.

Many applications demand ultra-low pressure sensors (Figure 1) that can provide extremely high accuracy, including designs as diverse as medical ventilators and variable air volume (VAV) control systems for building energy conservation. And more and more engineers are turning to board-mounted pressure sensors to address common problems such as limited space and reliability. 


Ultra-low, high-accuracy pressure sensors are available as board-mounted solutions that can measure absolute, gage, and differential pressure

Figure 1. Ultra-low, high-accuracy pressure sensors are available as board-mounted solutions that can measure absolute, gauge, and differential pressure. Image used courtesy of Honeywell.


Benefits of Board-Mounted Pressure Sensors

Board-mount pressure sensors (Figure 2) have become a popular choice for engineers working with applications that require low-pressure, high accuracy sensors. These compact sensors can easily be mounted on a PCB (Printed Circuit Board), allowing them to be directly integrated into the electronics assembly.

Their compact footprint addresses space constraints, and they utilize a microstructure that is highly sensitive to pressure changes (including absolute, differential, and gage) so that accurate, ultra-low pressure readings can be obtained.

In addition, the design of board-mounted pressure sensors means they are energy efficient.


Board-mount pressure sensors are very compact and easy to integrate into circuitry and electronics

Figure 2. Board-mount pressure sensors are very compact and easy to integrate into circuitry and electronics. Image used courtesy of Honeywell. 


Medical Applications for High Accuracy, Ultra-Low Pressure Sensors

Medical applications that require high-accuracy, ultra-low pressure sensors include:

  • hemodialysis machines
  • ventilators
  • anesthesia machines 
  • sleep apnea machines
  • medical chemistry

In hemodialysis machines depend on these pressure sensors to regulate pressure in the mixing tank as the blood approaches the artificial kidney and regulates blood flow to and from the patient. 

Alternatively in ventilators, they aid in monitoring a patient’s breathing and detecting if it suddenly deteriorates, in addition to detecting the presence of a clogged filter. High-accuracy pressure sensors serve a similar purpose in anesthesia machines as they measure the pressure of air and oxygen, both to and from the patient, to ensure it never exceeds a safe level.

Sleep apnea machines (Figure 3), including CPAP, Auto-PAP, and Bilevel-PAP, utilize ultra-low pressure sensors to monitor the pressure at which air is delivered to the patient. They are also used to monitor blood pressure and hospital room air.


High-accuracy, low-pressure board mount pressure sensors are used in ventilators and anesthesia equipment

Figure 3. High-accuracy, low-pressure board mount pressure sensors are used in ventilators and anesthesia equipment. Image provided courtesy of Pixabay. 


All in all, in medical chemistry, high-accuracy pressure sensors are used in chemistry analyzers. For example, pressure sensors are used with pipettes to draw the correct amount of fluid, detect if the vial is misplaced, verify that air is not being drawn in, and recognize the presence of obstructions. Additional applications include flow cytometry, molecular testing, and other categories of automated laboratory testing equipment.


Other Applications

There is also a need for ultra-low,high-accuracy pressure sensors in building energy conservation, such as monitoring the pressures related to filters to optimize when they are replaced, as well as determining if a filter is clogged or missing. High-accuracy pressure sensors may be used to the change in pressure associated with a window being open so that automated changes in airflow or window position adjustments can be made. 

They are also integrated into VAV systems to ensure that the airflow throughout a building is balanced. Ultra-low, high-accuracy pressure sensors can also be used in flow calibrators, pneumatic control, gas flow instrumentation, gas chromatography, and barometry, among others.

And all of these applications directly lend themselves to the use of board-mounted pressure sensor solutions.


Considerations When Selecting a Board-Mount Pressure Sensor

Selecting a board-mounted sensor involves the design choices typically involved with pressure sensors (e.g., operating pressure range, environmental temperature, type of media). However, to select the most appropriate high-accuracy, ultra-low pressure sensor from board mount product lines, there are considerations to be explored at more depth. 


Pressure Ranges and Burst Pressures

In some applications, there may be considerable uncertainty as to the pressure range in terms of the highest pressure as well as potential issues with burst pressure. Ranges that include a high working pressure (as opposed to the calibrated pressure range) can allow ultra-low pressure sensors to be continuously exposed to pressures above the calibrated range without harm. When combined with high burst pressures, the system design process can be simplified, potential system downtime reduced, and the overall reliability of the system enhanced. 



There are three basic types of error that can affect the accuracy of a pressure sensor: pressure non-linearity, hysteresis, and non-repeatability. Extremely tight accuracy, often measured in terms of FSS BFSL (Full Scale Span, Best Fit Straight Line), can improve system efficiency, reduce calibration requirements for the customer, make software development more simple, and minimize the design for the system. 


Total Error Band

The TEB (Total Error Band) takes into account errors related to accuracy as well as offset, FSS (Full Scale Span), thermal effect on offset, thermal effect on the span, and thermal hysteresis--all over the compensated temperature range. For a high-accuracy pressure sensor to provide accurate, reliable, and repeatable readings, the TEB must be considered.

There are other benefits to relying on TEB in addition to improving overall system accuracy. Selecting a board-mounted high accuracy pressure sensor with a low TEB also supports minimal part-to-part variation in accuracy which enhances the interchangeability of the sensors. Finally, pressure sensors with a small TEB decrease the manufacturing time and cost because every sensor does not require individual calibration and testing.



Stability is important to overall system performance and aids in minimizing calibration needs. It also supports the overall system uptime by minimizing the need for servicing or replacing the sensor. This is especially true for mission-critical applications such as those impacting health and well-being.


Energy Efficiency

The power consumption related to board-mount pressure sensors is extremely important for a variety of reasons, including their contribution to overall system performance. In addition, many of the applications for high-accuracy, low-pressure sensors must be portable, and low power consumption enables extended battery life. Even better are product lines that include an option sleep mode to further reduce power requirements.


Moisture Sensitivity Level 1

Pressure sensors that meet IIPC/JEDEC J-STD-020D.1 Moisture Sensitivity Level 1 requirement makes solder reflow attachment and/or repair a much safer process without the need for a lengthy bake. This allows the user to avoid the all too common mechanical and thermal damage that often results during reflow and supports lean manufacturing because the result is both stable and ready for use very quickly after the reflow process. In addition, meeting such strict standards related to moisture sensitivity also supports unlimited floor life when properly stored.


Example Product: Honeywell TruStability HSC

When applications demand highly-accurate, ultra-low pressure sensor solutions, board-mounted options are an excellent choice. The Honeywell TruStability HSC (High-accuracy Silicon Ceramic) Series of board mount pressure sensors are available in wide pressure ranges including  ±1.6 mbar to ±10 bar, ±160 Pa to ±1 MPa, and ±0.5 inH20 to ±150 psi with support for pressure bursts. They provide an industry-leading accuracy of ±0.25 %FSS BFSL calibrated over the temperature range of 0 °C to 50 °C [32 °F to 122 °F] and are temperature compensated at ±1% FSS to ±3% FSS TEB. 

The TruStability HSC (ultra-low pressure sensors are available for measuring absolute, differential, and gage pressures, all with excellent stability with extremely low power consumption (typically less than 10mW) with an optional sleep mode available upon request. 

Honeywell’s HSC series also meet IIPC/JEDEC J-STD-020D.1 Moisture Sensitivity Level 1 requirement. In addition, these ultra-low pressure sensors are fully calibrated and temperature compensated for temperature effects, sensitivity, sensor offset, and nonlinearity using an onboard application specific integrated circuit (ASIC).

Sager Electronics is an authorized stocking distributor of Honeywell Sensing and IoT, offering a broad scope of TruStability board mount pressure sensors as well as other sensor and switching solutions. Click here to find out more about these sensors, or visit the Honeywell catalog on  

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