This document describes the features and characteristics of CERAMIC SURFACE-MOUNT • 21.4MHz and 45MHz FUNDAMENTAL MONOLITHIC CRYSTAL FILTERS ASCF21U and ASCF45U, which are suitable for applications such as mobile communication systems, pagers, cellular and cordless phones, and radios.
The ASCF21U and ASCF45U are monolithic ceramic surface‑mount crystal filters designed for 21.4 MHz and 45 MHz fundamental frequencies. They feature a compact 1.5 mm maximum height, reflow‑compatible packaging, and excellent attenuation bandwidth.
These filters are intended for mobile communication systems, pagers, cellular and cordless phones, and radios. They operate from –20 °C to +70 °C and are supplied in tape‑and‑reel or other surface‑mount packaging options. Detailed electrical parameters such as passband/stopband ripple and impedance are listed in the specification tables.
| Fundamental frequency (ASCF21U) | 21.4 MHz |
|---|---|
| Fundamental frequency (ASCF45U) | 45 MHz |
| Package height | ≤1.5 mm |
| Operating temperature | -20 °C to +70 °C |
| Package type | Surface‑mount ceramic, reflow capable |
They operate from –20 °C up to +70 °C.
They are supplied in a surface‑mount ceramic package that is reflow capable.
ASCF21U operates at 21.4 MHz and ASCF45U at 45 MHz.