OSCILLATOR CIRCUIT AND CLOCK ACCURACY 关于32.768KHz时钟电路与时钟精准度,举例说明如下：

OSCILLATOR CIRCUIT时钟电路 

标称频率（Nominal Frequency）：32.768KHz

等效阻抗（Series Resistance）：45KΩ

负载电容（Load Capacitance）：6pF

For instance, Table 1 specifies 3 crystal parameters for the external crystal 32.768kHz. Figure 1 shows a functional schematic of the oscillator circuit. If using a crystal with the specified characteristics, the startup time is usually less than one second.

举例，表1指定了外部晶体32.768kHz的三个电气参数。图1显示了振荡器电路的功能原理图。如果使用指定规格晶体，则启动时间通常小于1秒。

CLOCK ACCURACY 影响时钟准确性的三个主要因素 

The accuracy of the crystal itself

晶体本身频率准确性

The accuracy of the match between the capacitive load of the oscillator circuit and the capacitive load for which the crystal was trimmed.

晶体负载CL与其应用电路负载电容匹配的准确性

Additional error will be added by crystal frequency drift caused by temperature shifts.

因为温漂原因，工作温度变化会影响频率精度

注： 

Some oscillator circuits does not require any external resistors or capacitors to operate.

一些振荡器电路不需要任何外部电阻器或电容器来工作。