晶振工作原理及制程.ppt

Nov. 20, 2001,Introduction of Quartz Crystal,Linda Lin / FAE Department,Contents,Characteristic of Quartz Material Characteristics of Crystal Units Choose the Right Crystal Unit,Characteristics of Quartz Material,Quartz Material Piezo Electricity Why is AT-Cut Frequency vs. Thickness Lapping & Etching,Quartz Material ( 1 ),材料成份： 二氧化矽 SiO2 材料組成： 正六方晶系 TRIGONAL-DIGONAL CLASS：32 材料特性：,熔點 1,750 1atm -相變點 537 1atm 硬度 7.2莫氏硬度 25 密度 2,648Kg/M3 25 壓電特性 Y軸： 機械軸 MECHANICAL AXIS 光雙折性 Z軸： 光學軸 OPTICAL AXIS,Quartz Material ( 2 ),Quartz Material ( 3 ),SYNTHETIC QUARTZ CRYSTAL,AUTOCLAVE HYDROTHERMAL METHOD RAW MATERIAL： Silica HIGH PRESSURE：800 to 2,000 atmospheres HIGH TEMPERATURE： 400 HIGH TEMP. STABILITY ： 0.2 LONG GROWTH TIME： 1 6 Month HIGH PURITY： Infra-Red Absorption (IRA)： 3585 CM-1,Piezo Electricity ( 1 ),The positive electric-field is induced when the mechanic force pull the Oxygen atom out of original position .,The negative electric-field is induced when the mechanic force push the Oxygen atom toward center position .,The SiO2 is always in the static state of electric neutrial .,Piezo Electricity ( 2 ),When a electric field applied , the induced electric filed is generated and force the Oxygen atom move outward .,The SiO2 is always in the static state of electric neutral .,When a electric field applied , the induced electric filed is generated and force the Oxygen atom move closer .,振動模式,長度彎曲振動 Length-width flexure 伸縮振動 Extensional flexure 輪廓振動 Face shear flexure 厚度振動 Thickness shear flexure,基 本 波：Fundamental 3 倍 頻：3rd overtone 5 倍 頻：5th overtone,Why is AT-Cut ( 1 ),Why is AT-Cut ( 2 ),Fundamental Movement,3rd Overtone Movement,20Mhz,60Mhz,0.082mm,0.082mm,+,-,+,-,Why is AT-Cut ( 2 ),Low Frequency CT +380 DT -520 ET +660 FT -570,High Frequency AT +35015 BT -490,各種切割角度 / 溫度 之關係,Why is AT-Cut ( 3 ),AT 切割角度 / 溫度 之關係,Why is AT-Cut ( 4 ),Frequency vs. Thickness,AT-Cut Crystal,F ( MHz) =,1670,T ( um ),F ( kHz) =,1670,T ( mm ),or,Laping Machinism,Laping & Etching ( 1 ),Surface Treatment & Etching,Laping & Etching ( 2 ),Note : The roughness and inter-crack data are dependet on the quartz material and the type of abbresive .,Roughness,Inter-Crack,Characteristics of Crystal Unit,Structure & Process Effective Circuit of Crystal Unit Parameter of Effective Circuit Measureing the Crystal Parameters,Structure of XTAL Dip Type,Structure of XTAL SMD Type,Metal Lid,Quartz Blank,Ceramic Base,Coated Electrode,XTAL Process ( 1 ),DIP 49U XTAL,Base plating,Blank cleaning,Annealing,Auto mount,Freq. adjustment,Curing,Sealing,Aging,F.Q.C.,O.Q.C.,XTAL Process ( 2 ),SMD XTAL,Alignment,Blank cleaning,Base Plating,Blank auto mount,Curing,Freq. adjustment,Annealing,Auto seam welding,Aging,Final Test,Fine leak test,Gross leak test,Laser marking,F.Q.C.,Taping,Effective Circuit of XTAL,等效電路,Co : Shunt Capacitance Cm : Motional Capacitance Lm : Motional Inductance Rr : Motional Resistance,Note : “ Motional “ means the Frequency Dependency .,Parameters of Effective Circuit ( 1 ),C0：Static ( Shunt ) Capacitance： 一般 C0 5.5pF 以下 ( Dip 49U ) 一般 C0 3.5pF 以下 ( SMD 7.0*5.0 ),C0=0.02 del ,fs n,The shunt capacitance include the capacitance of XTAL and stray cap. of paste , metal cap inside the package . Mounting system的改變 或 base 長度/材質 不同 C0 值會變化 0.2 pF1 pF 之間. C0小 起振電壓低，但CI較困難製造.,2,Cm：dynamic capacitance,C1=0.1Kcdel ,fs n3,f=Resonance Freqency del：Electrode Diameter n：Ordinal Number of Harmonics(1,3,5,7,) kc：Correction Constant kc=1fundamental oscillation kc=0.853rd over tone kc=0.755rd over tone,Parameters of Effective Circuit ( 2 ),2,Lm：Dynamic Inductance,L1=,1 Ws2C1,低頻時，晶片較厚，WAFER較大數HENRIES 高頻時，晶片較薄，BLANK較小數mH,1 2fsC1,=,由 Mechanical Mass 決定大小,Parameters of Effective Circuit ( 3 ),R1：Dynamic Resistance.(Rr),R=P,L A,，A，R,相關原因：,(1) 音響學上的損失 晶片表面平行度 大氣R1 N2R1 真空中R1 石英晶片表面清潔度 晶片表面與鍍膜層附著性 電極面之設計 石英原料材質 石英晶片表面處理,Parameters of Effective Circuit ( 4 ),Measuring the Crystal Parameters,Calculation Method Measurement Method Physical Load Method,Pi NetWork Method,Oscillation Method,Choose the Right Crystal,Principle of Oscillation Characteristics of Load Capacitance Pullability & Trim & Q-value Read the Testing Data Setting the Specification,Principle of Oscillation,振盪原理,Principle of Oscillation ( 1 ),振盪原理,Gain Curve of Osc Circuit,Principle of Oscillation ( 2 ),振盪原理,Gain Curve of Osc Circuit,Principle of Oscillation ( 3 ),振盪原理,Gain Curve of Osc Circuit,Principle of Oscillation ( 4 ),負性阻抗 ( - R ),- R,Frequency,10.0,20.0,30.0,40.0,50.0,從 XTAL 兩個端點 向振盪線路看進去之 頻率 對 阻抗 關係,Characteristic of Load Capacitance ( 1 ),Characteristic of Load Capacitance ( 2 ),Load Capacitance CL CL=CdCg+Cs=CgCd / (Cd+Cg)+Cs Cs：Stray Capacitance 一般23pF FL = FR * ( 1 + C1 / 2 * ( C0 + CL) ),CL 愈小，Cs 影響愈大，愈不穩定 CL 太大，雖 Cs 影響小，但 power 必須加大，耗電 建議： CL 以 18 20pF為主 電容成本低不要省， 且應利用Cd/Cg來調整CL， 而非用XTAL來就電容,Characteristic of Load Capacitance ( 3 ),FL = FR * ( 1 + C1 / 2 * ( C0 + CL) ),CL=CdCg+Cs,Pulling Range From CL1 CL2 ：,Pullability & Trim & Q-value ( 1 ),DL=,FL1- FL2 FR,=,C1(CL2-CL1) (C0+CL1)(C0+CL2),S =,d FL d CL,C1 2(C0+CL) 2,Trim Sesitivity at CL ：,Extremely Important,Pullability & Trim & Q-value ( 2 ),Pullability & Trim & Q-value ( 3 ),Fund or 3rd ?,Fund or 3rd ?,Q 值：the quality of quartz XTAL,Q =,2* * Fr * Lm R1,1 2* * Fr * R1 * Cm,=,Is there any relation between Q-value and Pullability ?,Pullability & Trim & Q-value ( 4 ),Read the Data ( 1 ),Read the Data ( 2 ),Read the Data ( 3 ),This Spectrum is only shown in XTAL unit . Not in exact output of oscillated circuit . Why ?,Read the Data ( 4 ),Read the Data ( 5 ),Read the Data ( 6 ),Setting the Specification ( 1 ),Genaral Specifications,Package Type & Dimensions E