Sumida was established in 1956 and soon developed to be one of the main coil manufacturers in Japan. They were the first to venture into China, and later strengthened their leading position in the coil industry by introducing a wide range of power inductors for various applications.

Sumida manufactures and sells signal products (such as RF transformers or coils for high-frequency circuits in all electronic devices), power solution products (such as transformers for DC-DC converters, switching power supply and common mode choke coils), as well as power inductors that were first commercialized by them.

Sumida components are targeted for use in general electronics devices such as audio-video equipment, home electronic appliance, office automation equipment, in-car equipment, communication equipment, measurement hardware, machine accessory and medical equipment.

The CDRH series is a surface mount power inductor where the electrode is attached to the ferrite core directly. Parts are also magnetically shielded to reduce EMI effects. These are drum core, ring-core shaped parts with metal electrodes.