Ultra-compact crystal unit preserves ESR characteristics lost when miniaturised

Murata has introduced what is claimed to be the world's smallest 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 ESR and by decreasing the size of its previous crystal unit to a miniscule 1.2mm x 1mm, the new product contributes greatly to size reduction for mobile equipment and modules. With most crystal units, ESR worsens when the vibrating area of a crystal is restricted due to the effects of miniaturisation. However, the company 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, It uses a structure that distributes stress at the time of moulding and hence assures dielectric strength. Conforming to RoHS regulations, the 37.4MHz XRCED37M400FXQ52R0 crystal unit is lead free (phase 3) and allows lead-free soldering. The component offers a frequency tolerance of +/-20ppm across a temperature range of -30C to 85C. The maximum ESR is 60ohms and the drive level is 100microwatts maximum.