1、ANSI/EIA-512-1 ADOPT ION NOT I CE ANSl/EiA-512-1, OlStandard Methods for Measurement of the Equivalent Electrical Parameters of Quartz Crystal Units, 1 kHz to 1 GHz,“ was adopted on 12 September 1994, for use by the Department of Defense (Da). Proposed changes by DoD activities must be submitted to
2、the DoD Adopting Activity: Laboratory, ATTN: AUSRL-EP-RD, Fort Monnouth, NJ 07703-5601. standard from the Defense Printing Service Detachment Office, Building 4D (Customer Service), 700 Robbins Avenue, Philadelphia, PA 19111-5094. ALL private sector and other Goverwnt agencies may purchase copies fr
3、om the Electronic Industries Association, 2001 Eye Street, N.U., Uashington, D.C. 20006. U.S. Army Research DoD activities may obtain copies of this Custodians: Amr/ - ER Navy - EC Air Force - 85 NASA - NA Review Activities: Army - AR, MI, SM Navy - AS, CG, MC, OS. SH Air Force - 17, 19, 99 MSC N/A
4、1 of 1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Adopting Activity: Army - ER Agent: DLA - ES (Project 5955-0634-01 ) FSC 5955 r I a In I w l- a - EIA 532-3 90 W 3234b00 0072873 8 = APPROVED: November 12, 1990 EIA STANDARD Standard Methods dor Measurement of t
5、he Equivalent Electrical Parameters of Quartz Crystal Units, 1 kHz to 1 GHz EIA-512-6 (Addendum No. 1 to EIA-512) DECEMBER 1990 ELECTRONIC INDUSTRIES ASSOCIATION ENGINEERING DEPARTMENT EIA 512-1 90 3234b00 0072872 T W D b NOTICE EIA Engineering Standards and Publications are designed to serve the pu
6、blic interest through eliminating misunderstandings between manufacturers and purchasers, facilitating interchangeability and improvement of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for his particular need. Existence of such Standards and
7、 Publications shall not in any respect preclude any member or nonmember of EL4 from manufacturing or selling products not conforming to such Standards and Publications, nor shall the existence of such Standards and Publications preclude their voluntary use by those other than EIA members, whether th
8、e standard is to be used either domestically or internationally. Recommended Standards and Publications are adopted by EL4 without regard to whether their adoption may involve patents on articles, materials, or processes. By such action, ETA does not assume any liability to any patent owner, nor doe
9、s it assume any obligation whatever to parties adopting the Recommended Standard or Publication. This EIA Standard is considered to have International Standardization implication, but the International Electrotechnical Commission activity has not progressed to the point where a valid comparison betw
10、een the EIA Standard and the IEC document can be made. This Standard does not purport to address all safety problems associated with its use or all applicable regulatory requirements. It is the responsibility of the user of this Standard to establish appropriate safety and health practices and to de
11、termine the applicability of regulatory limitations before its use. (From Standards Proposal No. 2200 formulated under the cognizance of the EIA P-11 Committee on Quartz Crystals.) COPYRIGHT 1991 Published by ELECTRONIC INDUSTRIES ASSOCIATION Engineering Department 2001 Pennsylvania Ave. N.W., Washi
12、ngton, D.C. 20006 PRICE: Please refer to the current Catalog of EIA even users who buy “complete“ measurement systems, which include equipment, fixtures, and software, must still be aware of how to make accurate measurements and how to verify system performance. This guide will provide the needed in
13、formation to do so, EIA-512 is complete in describing scattering parameter (S-parameter) theory, error correction techniques and in deriving the quartz crystal electrical parameter equations. For that reason, no attempt is made to review or summarize the standard. Instead, only information that adds
14、 to the understanding and use of the standard is included in the guide. Some material from the IECs Technical Committee No. 49 document, “A Guide To The Measurement of Equivalent Parameters Of Quartz Crystal Units“ was used in preparing this guide. EIA 512-1 90 W 3234600 0072875 5 M EIA-5 12 - 1 Pag
15、e 2 2.0 OVERVIEW OF MEASUREMENT METHODS 2.1 EQUIVALENT NETWORKS A proper equivalent circuit should represent the entire crystal unit as seen from the reference plane at the test fixture. It should include all the effects of leads, mountings and enclosure. It should also include crystal parameter dep
16、endency on frequency, drive level, and temperature. The effects of any mechanically or electrically coupled modes should be taken into account. Except for any nonlinear amplitude behavior, a quartz crystal unit can be quite accurate1 represented by the equivalent circuit in Figure 2.1 A description
17、of each circuit element I ollows: cPl The electrical surrounding ground planes. capacitance between each connecting pin and the The electrical capacitance between the pins. The equivalent resistances of the mounting structure. The electrical capacitance between the two electrodes. The electrical cap
18、acitances between the electrodes and the surrounding ground planes. The resistance between the electrodes. cPP Rpl, Rp2 Ce Ce19Ce2 RS I The equivalent electrical parameters of the design mode of resonance. R,N, L,N, C1,N The equivalent electrical parameters of other modes of resonance. here so that
19、the user is aware that complete characterization of a quartz crystal requires careful interpretation of measurements. The frequency and quality of the unit under test should be taken into account. Fortunately, this degree of sophistication is seldom needed. The circuit is reproduced For most applica
20、tions the following conditions are valid: a) Within a couple of percent frequency range of the mode of interest, there are no effects of interfering modes. Stated another way, R1, L1, C1 are constant over the frequency range of interest. b) $1 =RPl2+ ($1)/ and Xp2=Rp22+ are each much less than XI =
21、R12+ (wL1- l/wCl) 3 2 1/2 -EIA 512-1 90 3234600 0072876 7 W (This condition should be checked for frequencies above 300 MHz.) c) R, Xi The following terms can be combined: EIA- 5 12 - 1 Page 3 e) Co = Ce + Cpp This results in the simplified equivalent circuit of Figure 2.2a for a two-port, three ter
22、minal quartz crystal. For a one-port measurement, the stray capacitances are combined with Co and the equivalent circuit can be represented as shown in Figure 2.2b. This circuit representation is also used for glass enclosed quartz crystals regardless of whether the two-port or one-port method is us
23、ed. Since the stray capacitances will differ in each case, the values of Co will not be the same. (Fs) (the series resonance frequency of the series arm) is relatively independent of Co and any stray capacitance, it should be used to correlate EIA-512 one-port and two-port d measurements. When selec
24、ting crystals to correlate other measurement systems, select those units that do not show motional parameter dependency on small variations in drive level. Also select units that exhibit a good circle fit in the admittance plane. A good fit guarantees that there are no interfering modes of vibration
25、 over the frequency range used for the measurement. Units that are not “well behaved“ cannot be represented by the simplified equivaIent network. They can still be measured using EIA-512 but attempts to correlate these measurements with other test systems will yield erroneous results. 2.2 CLASSIFICA
26、TION OF MEASUREMENT SYSEMS In the general case the quartz crystal unit must be treated as a three terminal network the third terminal being in the typical case a metal enclosure, which should be grounded. Three types of connection of the crystal unit are possible : -One-port (two-terminal) in which
27、one of the pins (leads) is grounded while the enclosure is floating; -One-port (two-terminal) in which one of the pins (leads) is grounded and the enclosure is also grounded; a -Two-port (three-terminal connection in which only the enclosure is grounded. EIA 512-1 90 3234b00 0072877 9 EIA-512-1 Page
28、 4 The true values of the motional arms of the quartz crystal unit equivalent circuit (for the main resonance : series resonance frequency Fs, motional resistance R1 and motional capacitance C1 or inductance L1) are practically independent of the type of connection. The type of connection strongly i
29、nfluences the distributed (static) capacitances. The influence of distributed capacitance is different in various measuring methods and different applications, so it is important to specify the crystal pin connection to be used. In the general case, the characterization of quartz crystal units requi
30、res many measurements made at different frequencies near series resonance, and it is rather complex to form an estimate of the equivalent circuit parameters that will best approximate the electrical behavior of the unit. Fortunately, in most cases only a few of the crystal equivalent parameters need
31、 be determined, particularly in the production environment. The most important are two parameters: series resonance frequency Fs, and motional resistance R1; in a large number of cases, these may be approximated measurement of zero-phase frequency fr and zero-phase insertion resistance Rr. These lat
32、ter two parameters may be measured with limited accuracy by simple and fast single frequency methods. From the point of view of general principle the most important measuring methods may be classified as follows: Q A. Oscillator methods (also called active methods) in which the frequency of oscillat
33、ion of special oscillator circuits, into which the crystal unit to be measured is connected, is measured and assumed to be the zero-phase frequency of the crystal unit. B. Transmission methods in which the crystal unit parameters determined indirectly from measurements of the transfer function of th
34、e network formed by connecting the crystal unit (enclosure grounded) into a resistive network. Transmission methods may be divided into four subgroups: 1. Extremum transmission methods (ETM) in which is used only information about the magnitude of the transfer function. The crystal unit frequency is
35、 identified as that at which the extremum (maximum) output voltage occurs. 2. Phase transmission methods (PTM) in which we use information about the transfer function phase. The crystal unit frequency is identified as that at which the output voltage phase is the same as that obtained during prelimi
36、nary calibration) in the ideal case the output voltage is in phase with the input voltage) . In these methods amplitude information is not needed to establish frequency of the unit, but must be obtained if the insertion resistance is to be calculated. Measuring sets using - or T- transmission networ
37、ks are the most important examples of equipment used for ETM or FTM. 3. Vector transmission methods (VTM) in which information about both the amplitude and phase of the transfer function is needed. In contrast to the ETM and PTM, which are fundamentally single frequency measurements, VTM typically r
38、equire measurements at several frequencies near resonance so that motional capacitance (or inductance) may also be determined. al 4. Scattering Darameter methods (SPM) in which all four of the two-port scattering parameters of the three-terminal crystal unit connection are determined, and fully corr
39、ected for linear errors in measuring system and fixtures, at several frequencies EIA 512-1 90 W 3234600 0072878 O W EIA-512-1 Page 5 near series resonance of the device. Such measuring sets require the use of dual-directional couplers and vector detectors, such as those incorporated in network analy
40、zers. C. Impedance (admittance) measuring methods in which one-port quartz crystal unit parameters are determined using the vector values of the crystal unit impedance (admittance) measured at several frequencies near resonance. The method of calculation is the same as for the SPM above, but the cry
41、stal is connected as a one-port (with one pin/lead grounded). Two subgroups of impedance measurement may be distinguished: 1. Direct immittance methods (DIM) in which equipment is used which reads out directly impedance (or admittance values) (e.g., various bridges or vector immittance meters). 2. R
42、eflection coefficient methods (RCM) in which the quartz crystal unit parameters are determined from the vector values of the reflection coefficient of the crystal unit connected to a system port of known impedance, at several frequencies. 2.3 AUTOMATED NETWORK ANALYZER METHODS Automatic two-port net
43、work analyzers have been developed for the general characterization of active and passive networks. These anaIyzers provide for the determination of the two-port scattering parameters of the network under test, and provide for correction of the measured responses to take into account imperfections i
44、n the equipment by referring network parameters to the network analyzer .S-parameter instruments of this type are now available. For use as crystal measurement systems, stable synthesized signal sources must be included in the system; some systems include such sources while others need to be modifie
45、d for this use. Such systems provide for calibration at the measurement reference plane with coaxial impedance standards, and are capable of very accurate and reproducible measurements. The use of the scattering parameter methods, originally developed for application to microwave systems, allows for
46、 the separation of the trans-immittance parameters from the effects of shunt elements, so test the C13 and C23 static capacitances may be separated from the transmission characteristics, and determined separately. Also, the test fixture imperfections are to at least a first approximation removed fro
47、m the measurement, as the “Calibration“ of the system is done at the measurement ports, and the error correction algorithms from the measurements the effects of the system up to the reference plane. These automatic network analyzer systems have proven to be the most satisfactory way of obtaining pre
48、cise measurements of immittance over very wide frequency ranges. Either one-port reflection measurements or two-port transmission measurements may be made as desired. For crystal unit measurements, the choice of one-port or two-port measurement is generally arbitrary, as the two yield essentially id
49、entical values for the motional parameters, differing only in the values of the static capacitances. As a guide, the following are general recommendations. L One-port measurements - Low resistance crystals (RI 100 ohms); crystals for filter 7. Fr EIA 512-1 90 m 3234b00 O072879 2 m EIA-512-1 Page 6 use and some exacting oscillator applications; high frequency crystals (Fs 100 MHz) . 2.4 COMPARISON MEASUREMENT METHODS Test and measurement of crystal units in a production facility pose some unique problems. Generally, high through-put is required, and devices are checked against sp
