TDK's high-performance waterproof barometer is sensitive to your every move:

Affected by the global epidemic, people's attention to personal health has generally increased, and their willingness to exercise is unprecedentedly high. It is expected that the demand for smart wearable products (smart watches, sports watches, bracelets) will have considerable growth in 2020.

TDK recently launched the industry's lowest power consumption, lowest noise, and thinnest package 10ATM waterproof barometer ICP-10125 to meet the needs of smart wearable products.

Figure 1 ICP-10125

ICP-10125 uses TDK's MEMS pressure sensor chip, which is specially optimized based on the capacitive principle, and is supplemented by TDK's experienced ceramic substrate chimney-style potting packaging, which perfectly matches the stringent requirements of wearable products for barometer performance and waterproofing.

Compared with resistive atmospheric pressure sensors, capacitive atmospheric pressure sensors have very obvious advantages, specifically in the following aspects:

Figure 2 Comparison of sensing principles

In view of the application characteristics of atmospheric pressure sensors in personal consumer electronic products, TDK has further optimized the power consumption and noise in sensor design. This is reflected in the product. Compared with competing products in the industry (including capacitive and piezoresistive types), ICP-10125 consumes the lowest current and outputs the lowest noise under the same settings.

Figure 3 Power consumption and noise comparison of competing products

Figure 4 ICP-10125 key parameters

In low-power mode, the average current consumption of ICP-10125 is only 1.3 microamps per second. Wearable products can keep the barometer open and continuously monitor environmental pressure changes/altitude changes, and the power consumption paid for this is negligible compared to the overall system power consumption. Even working in ultra-low noise mode (which can meet ultra-high precision measurement of pressure or altitude), the average current consumption of ICP10125 per second is only 10.4 microamps.

ICP-10125 can dynamically work in different modes according to the different requirements of the application for measurement accuracy. In ultra-low noise mode, the output pressure noise (RMS) of ICP-10125 is only 0.4 Pa, which corresponds to the output noise (RMS) of height measurement in atmospheric environment is only ~3.4 cm (0.4 Pa x ~8.5 cm/Pa). Corresponding to the height measurement application, ICP-10125 can accurately measure the height change of more than 3.4 cm. In other words, the effective resolution of ICP-10125 for height is 3.4 cm.

Figure 5 Step recognition

As shown in the measured data above, the ICP-10125 can accurately detect the air pressure change (2.1 Pa) caused by each step (18 cm) the user takes, while the output noise of competing piezoresistive barometers under similar configurations is much higher than 2.1 Pa, so it is completely unable to identify the corresponding air pressure changes.

Combining the above outstanding advantages of low power consumption and low noise, ICP-10125 can help customers enrich application scenarios in wearable products and realize applications that cannot be achieved based on piezoresistive barometers.

Figure 6 Unique Application

As shown in the figure above, in wearable products, ICP-10125 continuously tracks the centimeter-level height changes of users. With the motion sensor data (acceleration, angular velocity), the algorithm fusion processing can accurately identify and record the user's going up and down stairs, taking escalators or elevators, walking on flat ground or taking public transportation, walking up and down slopes or taking public transportation. In short, ICP-10125 can enable wearable devices to fully and detailedly record the user's all-weather movement methods and processes.

Motion recognition and recording are the most basic and important applications of wearable products. Currently, most products on the market use motion sensors (accelerometers and gyroscopes) to sense motion data (acceleration and angular velocity), and use motion algorithms to roughly identify motion patterns and record the motion process. However, there are usually problems with recognition rate and accuracy, because the data collected by motion sensors in two different motion modes may be very similar. Now, ICP-10125 is used to detect centimeter-level height changes, and the height information and motion data are integrated, which greatly improves the recognition rate and accuracy.

Waterproof is a basic requirement for wearable products. Users will wear smart watches and bracelets to swim, shower, play in the water, etc. The overall product needs to meet the waterproof requirements of 5ATM or even 10ATM. In terms of structural design and assembly, it is usually treated to be close to sealing. However, the barometer needs to sense the atmospheric pressure of the external environment. It cannot be sealed in the shell of the wearable product like other components, but must be connected to the external environment (atmosphere).

ICP-10125 adopts chimney-style glue-filling packaging to meet the high-specification waterproof requirements of wearable products while taking into account the performance of air pressure sensing.

Figure 7 Packaging features

The right half of the picture below shows the relevant structural design of ICP-10125 in wearable products.

Figure 8 Structural design

Compared with barometers using conventional packaging, products using ICP-10125 have obvious advantages in waterproof reliability, air permeability and convenience of production line assembly.

The above introduces the characteristics of TDK's recently launched waterproof barometer ICP-10125 and its special applications in wearable products. ICP-10125 has been highly recognized by many wearable product customers around the world and is used in the design of new products. Many smart wearable products equipped with ICP-10125 will be launched on the market this year. With a small sensor worn on your wrist, you will know more about your every move.