NAH-20-101-D

Power Line Filter Modules are devices used to filter out unwanted frequencies from the power supply lines. The NAH-20-101-D is an example of a Power Line Filter Module. This filter module is designed to reduce conducted interference from entering and leaving the system. It has the capability to provide up to 40dB (47-1000MHz) of conducted emissions attenuation in compliance with CISPR22, Class B standards and up to 25dB (1000-1800MHz) in compliance with CISPR22, Class A standards.

The NAH-20-101-D has two modes of operation. The first mode, named ‘Series Mode’, is the normal mode used for circuits which must meet conducted emission limits as specified by CISPR22 standards. In this mode, the filter acts as a low-pass filter with a cut-off frequency determined by the components used in the circuit design. The filter elements used in this mode provide attenuation from 47MHz to 1800MHz, with a low pass cap in parallel with the inductor to provide additional attenuation high frequencies above 1800MHz. The second mode, titled ‘Shunt Mode’, is used when the filter is employed to reduce the power supply’s susceptibility to radiated interference. In Shunt Mode the filter acts as a high-pass filter, attenuating frequencies lower than the cut-off frequency and passing higher frequencies unaffected.

The NAH-20-101-D is constructed with high-grade metalized polypropylene construction for improved durability and improved attenuation ratings. The device contains two filter elements, one which is dedicated to high frequency signals and the other is dedicated to lower frequency signals. Each filter element is contained in an individual case in order to ensure that no undesired interference is passed from one to another. Additionally, the device has two 0.05µF capacitors in parallel located between the filter elements to prevent parasitic oscillations and provide optimal attenuation.

The NAH-20-101-D has a thermal performance of 96oC with an Impedance of 50 Ohms and a VSWR of 2.5 : 1. The device has a high insulation resistance prepared for grounding, with a 45dB minimum isolation when tested with a 100V DC applied. Finally, the device is tested to meet a Wideband Insertion Loss of -40dB, with an operational bandwidth of 1MHz – 1GHz and a minimum insertion loss of -20dB at 100MHz.

The NAH-20-101-D is a highly effective power line filter module designed to offer both series and shunt mode attenuation functions. It provides a maximum attenuation of 40dB in series mode and 25dB in shunt mode, in order to meet CISPR22 emission standards. The module’s thermal performance and insulation resistance are both excellent, and its operational bandwidth and insertion loss are also excellent. Overall, the NAH-20-101-D is an excellent filter module that is capable of offering excellent attenuation and performance for both conducted and radiated interference.