Noise Absorbers Reduce Voltage Ringing in Switch-Mode Power Supplies

TDK Corporation has developed the YNA15 series of noise absorbers in case size 1005 (IEC) to suppress voltage ringing that can be caused by switch-mode power supplies (SMPS). The new TDK noise absorbers have a rated voltage of 25 V and a rated capacitance of 0.1 µF. Depending on the type, the YNA15 series features ESR values of between 50 mΩ and 1 Ω. When the new component is used on the input side of the SMPS, for example, EMI noise caused by voltage ringing can be reduced by 3.5 dB (or approximately by one third). The YNA15 series thus effectively suppresses voltage ringing without reducing the power efficiency. A further benefit of the YNA15 series is that it can replace three components: the resistor and capacitor in the snubber circuit and the decoupling capacitor. Mass production began in November 2012.

Due to their design, SMPS may require capacitors with higher ESR values than offered by standard MLCCs. In order to meet these requirements and to suppress unwanted EMI noise, TDK developed an internal electrode structure that enables the design of noise absorbers with any desired ESR rating. As a result, EMI noise can be suppressed effectively in the frequency range where the voltage ringing occurs.

In recent years, smartphones and other compact portable devices have evolved toward integrating more and more functions. This in turn leads to higher power consumption and requires optimal design to ensure a suitably long battery life. Noise control in power supplies therefore must be implemented with as few components as possible and without compromising power efficiency. The new YNA15 series can satisfy such needs.