SCES469F August 2003 – March 2020 SN74LVC1404
PRODUCTION DATA.
请参考 PDF 数据表获取器件具体的封装图。
Figure 4 shows a typical application of the SN74LVC1404 device in a Pierce oscillator circuit. The output voltage can be conditioned further by connecting OSCOUT to the Schmitt-trigger input inverter. The Schmitt-trigger input inverter produces a rail-to-rail voltage waveform. The recommended load for the crystal, shown in this example, is 16 pF. The value of the recommended load (CL) can be found in the crystal manufacturer's data sheet. Values of C1 and C2 are chosen so that and C1 ≉ C2. Rs is the current-limiting resistor, and the value depends on the maximum power dissipation of the crystal. Generally, the recommended value of Rs is specified in the crystal manufacturer's data sheet and, usually, this value is approximately equal to the reactance of C2 at resonance frequency, that is, RS = XC2. RF is the feedback resistor that is used to bias the inverter in the linear region of operation. Usually, the value is chosen to be within 1 MΩ to 10 MΩ.