Capacitive Pressure Sensors

Product OverviewCapacitive Pressure Sensors ICP-101xx Series

Capacitive Pressure Sensors ICP-101xx SeriesThe TDK ICP-101xx pressure sensor family is based on MEMS capacitive technology which provides ultra-low noise at the lowest power, enabling industry leading relative accuracy, sensor throughput, and temperature stability.

Capacitive Technology

Capacitive pressure sensing technology overcomes many of the challenges of the previous piezo resistive technology and improves overall performance. Below is a comparison of the 2 architectures:

Figure 1 Capacitive Technology

Capacitive Pressure Sensor Advantages

Piezo resistors

Strain Measurement

Capacitive Technology  piezo resistors

Membrane,
top-view

Detect diaphragm deflection by stress
Convert stress to electrical signal

Capacitive

Measure of Capacitance

Capacitive Technology  capacitive

Membrane,
side-view

Directly convert diaphragm
deflection to electrical signal

Advantages of Capacitive pressure sensors:
  • Lower power: No current consumption during capacitance measurement
    • ✓Lower power at same performance
    • ✓Better performance at same power consumption
  • Lower noise: Thermal noise of piezo resistors fundamentally limits sensitivity/resolution
  • Better temperature stability: Piezo resistors are highly sensitive to temperature
  • High Accuracy: Capacitive principle enables greater sensitivity and resolution to pressure changes

Capacitive Pressure Sensor Performance

Noise and Power

The capacitive pressure sensor architectural advantage enables unparalleled levels of ultra-low noise and power beyond what piezo resistive sensors can deliver. Below is a chart of noise and power of TDK’s ICP-101xx capacitive pressure family vs common industry piezo resistive pressure sensors at an output data rate of 1Hz:

Figure 2 Noise and Power
Noise and Power

The ICP-101xx pressure sensor family has a noise floor under 0.4Pa-rms enabling pressure measurement differences of less than ±1 Pa, an accuracy enabling altitude measurement differentials as small as 5 cm, less than the height of a single stair step.

Figure 3 Lowest Pressure Noise & Relative Accuracy
Lowest Pressure Noise & Relative Accuracy
Video 1 Piezoresistive vs Capacitive Pressure Sensors

Temperature Stability

Capacitive pressure sensors are inherently more stable over temperature than piezo resistive based sensors since piezo resistors are highly sensitive to temperature variation. The ICP-101xx pressure sensor family achieves an industry leading temperature coefficient offset of ±0.5 Pa/°c making the device extremely stable over a wide temperature range.

Capacitive Pressure Sensors Enable New Use Cases

TDK’s capacitive pressure sensors, with ultra-low noise, ultra-low power, and temperature stability bring a new level of performance enabling new use cases not possible with incumbent piezo resistive technology.

Table 1 Capacitive Pressure Sensors Enable New Use Cases
Application New Use Cases
Wearable Improved motion tracking enabling activity identification and better caloric counting
Mobile Improved path of travel identification (stairs, escalator, elevator) provides improved indoor map routing and travel times, E911
Drones Improved altitude-hold and stability over a wide temp range enable a more stable flight control user experience
Datacom and Personal Inhalation Devices Sub pascal noise floor enables low threshold and high accuracy air flow measurement in a low profile package
Security Systems Measure vertical window displacement based on pressure instead of easily defeated accelerometers and reed switches