Silicon CapacitorsApplication for Ultra Broadband

The use of 400 Gbps Ethernet (400 GbE) is becoming mainstream in next-generation data centers, and R&D of Ethernet beyond 400 Gbps has already begun. The demand for higher speeds and wider broadband will continue to accelerate in the future.

Murata's silicon capacitors are ideal for use in ultra broadband optical communication devices.

Due to their unique structure, high capacitance stability over temperature and voltage, high capacitance density, and high integration technology, our silicon capacitors offer the best solution to improve signal integrity and implement miniaturization.

Target product:Transceiver、PON、PLT

Coupling capacitor

ULSC, BBSC, UBSC, and XBSC series are optimally designed for DC blocking (AC coupling) applications on high-frequency signal lines, and they offer low insertion loss, low reflection loss, and unique phase stability.
The capacitors are compatible with a wide range of high frequencies, from 16 kHz up to more than 100 GHz for the XBSC, up to more than 60 GHz for the UBSC, up to 40 GHz for the BBSC, and up to 20 GHz for the ULSC.

  • Single type

    Frequency Series
    20GHz ULSC
    40GHz BBSC
    60GHz+ UBSC
    100GHz+ XBSC
  • Differential type

    Frequency Series
    60GHz+ UBDC

Decoupling capacitor

WLSC, WBSC, and UWSC series are well-suited for decoupling applications in bias circuits, and they contribute to miniaturization where space is limited.
For example, only Murata's silicon capacitor technology is able to achieve a high capacitance density of 1 nF for the 0101 size (0.25 mm × 0.25 mm).

  • Wire bonding

    Frequency Thickness Series
    10GHz 100μm WLSC
    10GHz 250μm WBSC
    26GHz+ 100μm UWSC
  • Surface mounting

    Frequency Series
    20GHz+ ULSC

TOSA interposer

The use of Murata's silicon integrated passive device (IPD) technology enables both miniaturization and performance improvements for optical communication devices. For example, silicon interposers for TOSA enable the integration of all capacitors and resistors, which are conventionally mounted separately. This further improves stability in response to changes in temperature and voltage. As a result, it is possible to reduce the amount of mounting work, achieve miniaturization, and improve performance.

Key features

  • Coefficient of thermal expansion (CTE) near that of laser or EAM(4.2 ppm/K)
  • Same thermal conductivity as aluminum nitride (AlN) board(150W/m.K)
  • Dielectric constant=11.7
  • Loss tangent=0.005 @1GHz, 0.015 @10GHz


  • Improved reliability
  • Broadband compatible
  • Reduced size
  • Reduced number of components
  • Lower profile
  • Lower total costs

Substrate Design Support Tool

Silicon capacitor Matched Line

Assembly of Broadband Silicon Capacitors: Guidelines for improved Impedance Matching


Assembly Note

Assembly Note XBSC / UBDC / UBSC / BBSC / ULSC V1.6_Murata (PDF: 0.4 MB)


PDF Catalog

PDF documents related to silicon capacitors can be downloaded below

Commercial leaflet XBSC / UBSC / BBSC / ULSC V1.4_Murata (PDF: 1.9 MB)