Tiny crystal unit preserves ESR specs post-miniaturisation

January 11, 2017 // By Graham Prophet
Murata has introduced what it believes to be the smallest-available high precision crystal unit for use in mobile equipment and modules that use wireless technology such as Wi-Fi and Bluetooth – the XRCED series.

The crystal unit includes a unique technology that provides excellent low equivalent series resistance (ESR) despite its dimensions of 1.2 x 1.0 mm, suited to tighty-packed mobile equipment and modules.

 

With most crystal units, Murata says, ESR worsens when the vibrating area of a crystal is restricted due to the effects of miniaturisation. However, Murata has achieved very favourable ESR values by using a special packaging technology and high precision assembly. Normally the package is made low-profile to reduce the size of the crystal unit, but that leads to deformation of the package, and seal breakage. Accordingly, Murata uses a structure that distributes stress at the time of moulding and hence assures dielectric strength.

 

The 37.4MHz XRCED37M400FXQ52R0 crystal unit is lead free (phase 3) and allows lead-free soldering. The component offers a frequency tolerance of ± 20 ppm across a temperature range of -30 to 85 °C. The maximum ESR is 60 Ohms and the drive level is 100 µW maximum.

 

Murata Europe; www.murata.com