深圳市康华尔电子有限公司

诚信通第9年
咨询热线:0755-27838351
联系康华尔电话: 0755-27838351手机: 138 2330 0879Q Q: 632862232立即咨询邮箱: konuaer@163.com

晶振资料

来源:http://konuaer.com 作者:konuaer 2012年04月23
Kang Waldorf Electronics Co., Ltd. - quartz crystal design circuit Guide
Sport Waldorf electronics: the night of the continuous development of growth, from civil crystal, industrial crystal, military crystal, from the DIP crystal oscillator, SMD crystal, ceramic atomization piece, satellite navigation, SAW filter series.
From chip research and development, circuit design. The company already has the technology and development of production capacity, now some crystal design circuit, 32.768K kHz crystal matching capacitor, crystal match the IC, the crystal oscillation mode, the drive voltage and power, the welding temperature curve application published, I hope this can help to the needy and design to

Oscillation Circuit Design Overview
Oscillation Circuit Design Key Parameters
   DRIVE LEVEL (DL), OSCILLATION FREQUENCY AND LOAD CAPACITANCE (CL),
   OSCILLATION ALLOWANCE, FREQUENCY-TEMPERATURE CURVE
DRIVE LEVEL (DL)
The drive level of a crystal unit is shown by the level of the operating power or the current consumption (see Figures 9,10, and 11). Operating the crystal unit at an excessive power level will result in the degradation of its characteristics, which may cause frequency instability or physical failure of the crystal chip. Design your circuit within absolute maximum drive level.

OSCILLATION FREQUENCY AND LOAD CAPACITANCE (CL)
The load capacitance (CL) is a parameter for determining the frequency of the oscillation circuit. The CL is represented by an effective equivalent capacitance that is loaded from the oscillation circuit to both ends of the crystal unit (see Figure 12). The oscillation frequency varies depending upon the load capacitance of the oscillation circuit. In order to obtain the desirable frequency accuracy, matching between the load capacitances of the oscillation circuit and the crystal unit is required. For the use of the crystal unit, match the load capacitances of the oscillation circuit with the load capacitances of the crystal unit.
OSCILLATION ALLOWANCE
To ensure stable oscillation, the negative resistance of the circuit should be significantly larger than the equivalent series resistance (the oscillation allowance is large). Ensure that the oscillation allowance is at least five times as large as the equivalent series resistance.
Oscillation Allowance Evaluation Method
Add resistor "Rx" to the crystal unit in series and ensure that the oscillation starts or stops. The approximate negative resistance of the circuit is the value obtained by adding the effective resistance "Re" to the maximum resistance "Rx" when the oscillation starts or stops after gradually making Rx value larger.
Negative resistance |- R| = Rx + Re
|−R| is a value at least five times as large as the maximum equivalent series resistance (R1 max.) of the crystal unit.
*Re is the effective resistance value during oscillation.
Re = R1 (1 + CO/CL ) 2

FREQUENCY-TEMPERATURE CURVE

Frequency temperature characteristics of tuning fork crystals is shown by negative quadratic curve which has a peak at 25ºC as per left graph.
Please make sure to consider the temperature range and frequency accuracy you need since magnitude of frequency variation becomes larger and larger as the temperature range becomes wider.
[Approximation formula of frequency temperature characteristics]
f_tem = B(T-Ti) 2
B : Parabolic coefficient
T : Given temperature
Ti : Turnover temperature
正在载入评论数据...

发表评论:

姓名:
邮箱:
验证: 验证码
正文:

欢迎参与讨论,请在这里发表您的看法、交流您的观点。

  • 上一篇:
  • 下一篇:OCXO恒温振荡器晶体功能介绍
  • 诚征下列地区 晶振 | 石英晶振 | 圆柱晶振 | 贴片晶振 | 陶瓷晶振 | 石英晶体谐振器 | 频率元件 的合作伙伴:
    深圳市 广州市 北京 上海 东莞 佛山 中山 顺德 珠海 杭州 温州 武汉 长沙 南京 大连 长春 西安 郑州 澳门 沈阳 南宁 昆明 济南 重庆 成都
    有源晶振,表晶,石英晶振,,贴片晶振,声表面滤波器,陶瓷晶振,陶瓷雾化片,陶瓷滤波器,微孔雾化片,微孔雾化片,单片158KHz微孔雾化片,单片陶瓷雾化片,雾化片,进口晶振,F11声表面滤波器,TO-39声表面滤波器,3*3贴片声表面滤波器,KDS晶振,爱普生晶振,精工晶振,村田晶振,京瓷晶振,NDK晶振,NX3225SANDK晶振,NX5032GANDK晶振,有源晶振,温补晶振,KDS晶振DST310S,爱普生晶振FC-135,爱普生晶振MC-146,精工晶振SC-32S,精工晶振SSP-T7;
    在线客服
    在线客服
    close
    在线客服 康华尔微信号
    康华尔公众号