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E-mail
szcx17@163.com
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Phone
13631576199
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1F, Fenghe Park, Gongle Industrial Zone, Xixiang Avenue, Bao'an District, Shenzhen City, Guangdong Province
Shenzhen Chuangxin Instrument Co., Ltd
32.768KHz surface mount crystal oscillator tester successfully upgraded
Date: 2025-04-24Read: 0
Our 32.768KHz surface mount crystal oscillator tester improvement project has been successfully completed! This achievement embodies the wisdom and sweat of the entire R&D team, marking a new breakthrough for our company in the field of crystal oscillator detection technology. This improvement significantly enhances testing accuracy and efficiency, injecting stronger impetus into product quality control. We look forward to continuing to work together in the future to climb more technological peaks!
At present, the packaging sizes of 32.768KHz surface mount crystal oscillators in practical applications mainly include SMD2012, SMD3215, SMD7015, and SMD8038. For these crystal oscillators, many manufacturers are unable to test their incoming materials. To solve this problem, our company has specifically developed testing fixtures for those surface mount crystal oscillators. With the CX-118A crystal oscillator tester, various frequencies and errors of 32.768KHz surface mount crystal oscillators can be measured.
The role of 32.768Khz in circuits
1adopt32.768Khzthe reason
The frequency of 32.768Khz is widely used in circuit design mainly due to its unique mathematical characteristics. This frequency value can be easily divided into various commonly used time benchmarks through simple frequency division processing. For example, by dividing it by two using appropriate circuits 15 times, a 1Hz signal can be accurately generated, which is crucial for implementing timing functions in seconds. Moreover, the crystal oscillator at this frequency has high stability and can maintain relatively stable output under different environmental conditions, providing accurate and reliable clock signals for the circuit and meeting the high time accuracy requirements of application scenarios such as real-time clocks (RTC).
32.768KhzSelection of external loads
The external load has a significant impact on the performance of the 32.768Khz crystal oscillator. Choosing the appropriate load capacitor is crucial. The load capacitance value needs to be determined based on the specifications of the crystal and the specific requirements of the circuit. If the load capacitor is selected improperly, it may cause frequency deviation of the crystal oscillator, which in turn affects the timing accuracy of the entire circuit. Generally speaking, common load capacitance values are 7pF, 9PF, and 12.5pF. When designing circuits, it is necessary to consider the internal capacitance of the chip pins connected to them and select the appropriate external load capacitance through calculation to ensure that the crystal oscillator operates near its nominal frequency.
The following are the external capacitance values corresponding to common loads:
After actual matching testing, the optimal external capacitance value is recommended.
332.768KhzExternal circuit
The overall circuit of the crystal oscillator is shown in the figure. R1 provides bias for the inverter invl, allowing the MOS transistor to operate in the saturation region to achieve greater gain; C1, C2, and stray capacitance together form the capacitive load of the crystal, and together with the inverter invl, they can be equivalent to a negative resistance, providing the energy required for the crystal to oscillate; R2 is used to reduce the driving energy of the crystal to prevent crystal vibration or abnormalities; Inverter inv2 shapes the output waveform of invl and drives the load.