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General knowledge and quality control of the crystal

作者:admin  日期:2016-06-13 13:59:18

  General knowledge and quality control of the crystal

  The 1 is the role of crystal oscillator generates a clock signal, crystal resonator and other devices composed of crystal oscillator.

  2 crystal resonator to achieve good stability, resistance to small series resonant and good consistency, and the incentive power caused by the change of variable impedance is small, resonant crystal easily consistent, so the peripheral circuit debugging easier, make the product more stable, so how to achieve it? First, with the value of Q (Q value is the quality factor, dynamic arm at resonance in the equivalent circuit of the maximum stability of the oscillation circuit can be obtained directly with the circuit crystal Q value.Q value is high, the crystal bandwidth is small, the steeper the reactance value, external reactance on smaller crystals) of crystal materials, can reduce the series resistance at the same time to control the amount of glue symmetry; second, production workshop cleaning degree is high, can reduce the interference of dust outside the body attachment brings, to reduce the impedance variable; third, product testing will be parallel resonant resistance and DLD value (power The resulting variable impedance is controlled in a relatively small range.

  3 according to the characteristics of their experience and crystal summed up: first, in the process of using, the peripheral matching capacitance (including stray capacitance) near the crystal capacitance, oscillation frequency of the circuit formed closer to the nominal frequency. The stability of the circuit by the crystal itself and the peripheral circuit were decided, the best circuit should allow high working frequency and standard the frequency of about 8PPM, because the frequency of every year by about 3PPM year aging rate, so as to ensure the oscillation frequency of the circuit in 5 years with a high degree of accuracy; second, the crystal also has stability and shock resistance and weldability, how to achieve a certain temperature in use? 1) can improve the machining precision of the wafer. Reduce crystal closed shell nitrogen through the dew point, high and low temperature test; 2) production, with high quality plastic, and timely check point of baking glue, remove broken edge of the wafer, and drop by mechanical vibration test (100-2 0000G) test, improve packaging protection; 3) at the same time increase of 240 + 10 C and 5S conditions of high temperature test.

  4 crystal oscillator points (DIP-14, DIP-8) line and SMD line. The patch is generally non three state line, there is a demand optional three state specifications, type SMD for three state line output. In the use of DIP series 1# angle in no special instructions for disconnecting the electrostatic, less destructive to DIP.SMD 1# series of internal angle connected to external disconnect, electrostatic damage to the maximum, easy breakdown of IC, must make the electrostatic protection; in addition, a long series of SMD crystal in the process of welding temperature not too high, the time is generally controlled at 260 - 5 Deg. C, less than 5 seconds. It should be noted that the two side of the SMD crystal there will be some DLD test line, welding and not any solder joints connected. Crystal in use voltage 5V, 3.3V, 1.8V etc. are not compatible, otherwise it will not be stable.

  5 with the crystal has been widely applied to a variety of high-end equipment, the requirements are increasingly high, the voltage controlled crystal oscillator (VCXO), temperature compensated crystal oscillator (TCXO) and constant temperature crystal oscillator (OCXO) demand gradually increased.VCXO can adjust the output frequency of.TCXO comprises a temperature sensing circuit using changes in voltage to temperature changes is to adjust the output frequency, the output frequency is the deviation with the change of temperature is reduced, thereby maintaining their high frequency stability in a certain temperature range, accuracy generally has higher stability within 0-3PPM made of this kind of.OCXO, but also has lower phase noise, accuracy more, it is to maintain the temperature of the crystal stability through internal thermostat.

  Inspection technology and quality control of the crystal

  (a) crystal form, the conventional standard frequency error is /-20PPM impedance is an 30-40K but we actual inspection control: A: + 5ppm /15K Omega Phi 3 * 8; B: + 10ppm /15K omega; C: + 15ppm /18K Omega

  2*6 is divided into A: + 5PPM /25K B: + 10PPM; /28K; C: + 15PPM /30K.

  Customers can choose according to the requirements of the crystal, high requirements can choose the error and small impedance, such as A or B.

  (two) crystal resonator: the conventional standard is the frequency /-30PPM, plus strict control for /-20PPM impedance due to the frequency of different and variable, 2007 years ago: A form, today's parameter control is displayed in the B table:

  A form                                                                                     

49S晶体
49U晶体
频率
阻值
频率
阻值
3.579545M /4M
≤120Ω
1.8432M
≤500Ω
4.1M~5M
≤90Ω
2M
≤300Ω
5.1M~8M
≤60Ω
2.4576M
≤150Ω
8.1M~10M
≤50Ω
3M/3.2768M
≤120Ω
10.1M~12M
≤40Ω
3.579545M
≤90Ω
12.1M~30M
≤30Ω
4M
≤80Ω
30M以上
≤30Ω
4.1M~6M
≤60Ω
48M(泛音)
80-100
6.1M~7M
≤50Ω
 
 
8M~10M
≤40Ω
10.1M~20
≤30Ω


 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  B表格

49S晶体
49U晶体
频率
阻值
频率
阻值
3.579545M
≤95Ω
1.8432M
≤300Ω
3.6864M
≤80Ω
2.097152M
≤200Ω
4.000M/4.032M
≤80Ω
3.072M
≤90Ω
4.096M
≤75Ω
3.200M
≤60Ω
4.433619M
≤70Ω
3.579545M
≤65Ω
4.8970M
≤65Ω
4M
≤40Ω
5.000M
≤60Ω
5.000MM
≤30Ω
5.350M
≤50Ω
6.000M
≤20Ω
6.000M
≤40Ω
6.144M
≤20Ω
6.9567M-10M
≤30Ω
10.000M
≤20Ω
10.6M
≤20Ω
11.0592M
≤15Ω
10.8M
≤25Ω
15.360M
≤12Ω
11.0592M
≤25Ω
18.432M
≤10Ω
12.000M-18.432M
≤15Ω
20.000M
≤10Ω
20.000M-24.576M
≤12Ω
 
 
25.000M-27.2M
≤10Ω
 
 
28.224M
≤11Ω
 
 
28.322M
≤12Ω
 
 
30.000M-36.864M
≤15Ω
 
 
37.998M
≤20Ω
 
 
38.897M
≤20Ω
 
 
48.000M
≤45Ω
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

  In addition, only to the stringent requirements of these parameters is not enough, we in the other parameters including DLD value, Q value, and so on, on these parameters we through 250B authoritative testing instrument for detection and control, to ensure that customers can use the best quality of crystal devices.

  The SMD series is not listed in one by one.

  (three) crystal oscillator: This product in the control of our company is quite strict, for each parameter is the highest of all products, we will test the control parameters using PRA1020 test instrument. In addition to the control of the industry parameters, in strict control, we will further add more comprehensive testing requirements, such as the standard voltage is generally 5V or 3.3V, except to ensure the error in the standard voltage parameters under normal, we will carry out the parameter test in the upper and lower voltage, the 5V oscillator will detect 4.5V frequency error and voltage of 5.5V, 3.3V crystal will detect the frequency error and 2.97V under 3.63V voltage, and control the consistency of the site to watch the test process and the test data of different form. The different requirements of customers, customers can directly watch the screening process.

  Also for high stability crystal oscillator in pursuit of, we on the oscillator also electric performance testing of the vibration and temperature, in company with professional of high and low temperature impact test box, hot and cold temperature impact, test crystal temperature resistance; impact experiment equipment - LD vibration table, the seismic behavior of the crystal to test. We will also prepare additional charged high and low temperature for 48 hours aging control equipment. The purpose of our company is to achieve excellence in our koan products, to meet customer requirements of high quality, let koan brand crystal truly become the preferred customers.

 

  

 
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