Pi design shrinks EMI suppression filter

March 07, 2017 // By Nick Flaherty
TDK has used a Pi filter design to achieve an LC filter for EMI suppression with dimensions of just 1.0 x 0.5 x 0.35 mm

The usual method for suppressing interference in the communication frequency bands of smart phones and other devices is to use capacitors or inductances, or a combination of these components. In contrast to discrete solutions, the MEM1005PP251T combines two capacitors and an inductance in the form of a Pi filter in a single component. As a result, 61 percent less space is required and there is a reduction in the overall number of components.

The filters are aimed at smart phones and base stations and volume production begins in March 2017.

Using a a custom design, the component offers very low-loss operation and a DC resistance of 0.8 Ω, which represents a reduction of 69 percent when compared to previous products. The new filter offers a rated current of 350 mA, which is 3.5 times more than the MEM1608P series. The new filter is also designed for a very wide temperature range from -55 °C to +125 °C, whereas previous series only covered the range from -40 °C to +85 °C. Due to expansion of rated current and the wide temperature range, it allows a high degree of design flexibility.

The attenuation in the frequency range from 700 MHz to 3 GHz, which is used by mobile communications, is in excess of 30 dB. This means that interference is extremely well suppressed and the reception sensitivity increases significantly.

In future, TDK will extend this product line to meet the design requirements for a broad spectrum of devices for wireless communication.

Details can be found at the Epcos website