1、JEDEC STANDARD Standard for the Measurement of CRE JESD340 (Previously known as RS-340 and/or EIA-340) NOVEMBER 1967 (Reaffirmed: April 1981, April 1999, March 2009) JEDEC SOLID STATE TECHNOLOGY ASSOCIATION NOTICE JEDEC standards and publications contain material that has been prepared, reviewed, an
2、d approved through the JEDEC Board of Directors level and subsequently reviewed and approved by the JEDEC legal counsel. JEDEC standards and publications are designed to serve the public interest through eliminating misunderstandings between manufacturers and purchasers, facilitating interchangeabil
3、ity and improvement of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for use by those other than JEDEC members, whether the standard is to be used either domestically or internationally. JEDEC standards and publications are adopted without reg
4、ard to whether or not their adoption may involve patents or articles, materials, or processes. By such action JEDEC does not assume any liability to any patent owner, nor does it assume any obligation whatever to parties adopting the JEDEC standards or publications. The information included in JEDEC
5、 standards and publications represents a sound approach to product specification and application, principally from the solid state device manufacturer viewpoint. Within the JEDEC organization there are procedures whereby a JEDEC standard or publication may be further processed and ultimately become
6、an ANSI standard. No claims to be in conformance with this standard may be made unless all requirements stated in the standard are met. Inquiries, comments, and suggestions relative to the content of this JEDEC standard or publication should be addressed to JEDEC at the address below, or call (703)
7、907-7559 or www.jedec.org Published by JEDEC Solid State Technology Association 2009 3103 North 10th Street Suite 240 South Arlington, VA 22201-2107 This document may be downloaded free of charge; however JEDEC retains the copyright on this material. By downloading this file the individual agrees no
8、t to charge for or resell the resulting material. PRICE: Please refer to the current Catalog of JEDEC Engineering Standards and Publications online at http:/www.jedec.org/Catalog/catalog.cfm Printed in the U.S.A. All rights reserved PLEASE! DONT VIOLATE THE LAW! This document is copyrighted by JEDEC
9、 and may not be reproduced without permission. Organizations may obtain permission to reproduce a limited number of copies through entering into a license agreement. For information, contact: JEDEC Solid State Technology Association 3103 North 10th Street Suite 240 South Arlington, VA 22201-2107 or
10、call (703) 907-7559 (Reaffirmed 4/81, 4/99) EIA STANDARD f or The Measurement of (Gel ELECTRONIC INDUSTRIES ASSOCIATION STANDARD RS-340 Formulated by JE 0 EC Semiconductor Device Council NOTICE EIA engineering standards are designed to serve the public interest through eliminating mis- understanding
11、s between manufacturers and purchasers, facilitating interchangeability and improve- ment of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for his particular need. Existence of such standards shall not in any respect pre- clude any member or n
12、on-member of EIA from manufacturing or selling products not conforming to such standards, nor shall the existence of such standards preclude their voluntary use by those other than EIA members whether the standard is to be used either domestically or internationally. Recommended standards are adopte
13、d by EIA without regard to whether or not their adoption may involve patents on articles, materials, or processes. By such action, EIA does not assume any liability to any patent owner, nor does it assume any obligation whatever to parties adopting the recommended standards. Published by ELECTRONIC
14、INDUSTRIES ASSOCIATION Engineering Department 2001 Eye Street, N. W., Washington, D. C. 20006 STANDARD FOR THE MEASUREMENT OF IC,j (From Standards Proposal No. 917 formulated under the cognizance of JEDEC Committee JS-8 on Consumer Product Devices.) 1. INTRODUCTION 1.1 This standard offers an easily
15、-measured parameter which is one of the significant characteristics in determining the stability of a transistor intended for small-signal operation. The measurement tech- nique allows rapid testing. Its close correlation to AC stability will help to establish the interchange- ability of a device. 1
16、.2 The symbol used for this common-emitter short-circuit feedback parameter is (CreI. The magnitude bars are included for three reasons: (a) They reflect the true nature of the parameter in that it is an admittance magnitude rather than a susceptance. (b) They eliminate the need for a minus sign. Th
17、is prevents the confusion prevalent when the maxima of a minus quantity are to be considered. Cc) They reduce the possibility of mistaking the parameter for the imaginary portion of a reverse transfer matrix parameter (C, for the Y-parameter or C, for the Z-para- meter). 1.3 The parameter is express
18、ed as a capacitance rather than an immitance because the latter is frequency dependent. It is desirable to allow easy correlation of the parameter with different measure- ment frequencies. (C,I as defined and measured very closely resembles C, (the short circuit Y-para- meter) which is the reason fo
19、r the subscript Ire”. 1.4 It fits directly into the usual stability equations. A typical example is the equation for stability for a narrow-band amplifier with single-tuned interstages. s= 2 (Gs + %e) oe + GL) 1 + cos (tire + $fe) W IGel lyfe I All of the terms in this equation except for IC,I are e
20、ither swamped by circuit constants or are rela- tively constant. 1.5 IC,I is easily measured on relatively inexpensive equipment. It is a “plug-in-and-read” type of measurement. Because it is not a bridge measurement no adjustments or balancing are required. Rs.340 Page 2 1.6 IC,J is a measurement o
21、n an active, full-biased, transistor. In this it differs from Ccb which is defined for zero emitter bias current. 1.7 It is a three-terminal admittance measurement. Thus it doesnt fall heir to the numerous dif- ficulties and inaccuracies of the two-terminal measurement, Cob. 1.8 The low frequencies
22、used enable the measurements to be more easily reproduced. Correlation is improved. It is granted that the measurement of feedback at the actual operating frequency is the more efficacious method for determining stability performance; but the intent of IC,eI is to provide a suitable means for judgin
23、g transistor interchangeability over the widest possible range of transistor types, applications, and frequencies. 2. DEFINITION 2.1 IC,eJ is a three-terminal admittance measurement. It is defined as the magnitude of the small- signal short-circuit reverse-transfer admittance, lYreI. of a fully-bias
24、ed transistor connected in the com- mon-emitter configuration, divided by the angular velocity, w. w is equal to 2 a f where f is the frequency of measurement. ICr,I is derived from the Y-parameters although it is not itself a Y-parameter by rigorous definition. 2.2 The definition of Y, is formally
25、derived through the matrix-defining set of simultaneous equa- tions for the two-port network representation of a common-emitter-configured transistor. b c r-0-_- 0 7_ 0 7 “be i Lc; ; I 7%. D D -o-e-_-_ Ib = Yie “be + Yre Vce Ic = Yfe “be + yoe “ce us.340 Paps3 The definition of Y, is mathematically
26、expressed as: *b Y, = - V ce Vbe = zero 2.3 Insert this definition of Y, into the definition of IC, I 3. DISCUSSION 3.1 For more of an understanding of what lC,eI is physically, Y, can be broken down into its rectilinear components. (The subscript, s, refers to the fact that the Y-parameters are sho
27、rt-circuit parameters.) Y re = gres + ju cres The frequency of measurement should be chosen within the range where the magnitude of w C,s is at least ten times greater than the magnitude of g,. Then Y, can be considered to be purely capacitive. That is: C lyre I res = - w For most practical purposes
28、, IC, I can be taken to be equal to ICres 1 in this frequency range. 3.2 C, is normally expressed in minus picofarads. The minus sign for capacitive feedback is the result of the conventional polarity assignments of voltage and current for a two-port network. Refer to the diagram in Section 2.2. It
29、does not mean that the feedback is inductive. (C,e(, on the other hand, does not have this polarity confusion because it is defined in terms of a magnitude and therefore is always positive. 3.3 IC,I can be related to the hybrid -II equivalent circuit as well as to the matrix equivalency. If the phys
30、ical capacitance between the base and collector leads with the semi-conductor chip removed and the case grounded (three-terminal measurement) is known, it can be substracted from the measured value of IC,I and the difference will be a very close approximation of Cc in the hybrid -a network. RS-340 P
31、age 4 4. MEASUREMENT 4.1 Method 4.1.1 The method of measurement of IC,eI must implement its formal mathematical defini- tion. It is necessary to use that form of the definition which is expressed in physical rather than abstract qualities. From Section 2.3: IcreI =A I$ Vbe = ET0 4.1.2 The transistor
32、 under test is connected in the common-emitter configuration with the required bias conditions. See Figure 1. A fixed sinusoidal voltage of the desired frequency is applied across the collector-emitter terminals. A suitably small current-sampling resistor is used to provide a short between the base-
33、emitter terminals. The voltage across this current-sampling resistor is directly proportional to IC,I. 4.2 Frequency The frequency of measurement shall be chosen such that the magnitude of w C, is at least ten times greater than the magnitude of gres. FIGURE 1 W-340 PW5 2.5 mm MAXIMUM 4.3 METAL PANE
34、L FIGURE 2 Test Socket 4.3.1 The transistor test socket shall consist of four metal guide tubes so arranged as to ac- cept (and enclose) the lead wires of a transistor; these tubes to be imbedded in an insulating material suitable for the frequency of measurement. See Figure 2. The spacing of the gu
35、ide tubes shall conform close enough to the spacing of the transistors leads so that misalignment deformation will not prevent the transistors header from bottoming against the test socket. The guide tubes shall extend as close to the top surface of the socket as possible and still pro- vide insulat
36、ion from the transistor header but in no case shall be further than two and one-half millimeters from the top surface. The guide tubes may or may not contain wiping type con- tacts, but if they do not, then the inner diameter of the tubes shall be small enough to insure that electrical contact shall
37、 be made with the leads of the transistor. They shall be long enough to completely contain the transistors lead wires when the transistor is pushed down firmly against the test socket. In this manner the capacitance measurement will be independent of the length of the transistors leads. The transist
38、ors header shall be bottomed against the test socket during the measurement. RX340 Page 6 l l-ii R5340 Page 7 4.3.2 The test socket shall be mounted in a metal panel and the bottom, or lead portion, of the socket shall be totally inclosed in a grounded metal container so as to reduce the effects of
39、hand capacitance and stray fields. Provision shall be made for feeding the bias voltages and currents through the shielding to the socket terminals. The wires connecting the constant RF voltage generator and the metering circuitry to the socket should be shielded. 4.3.3 Cancellation of the residual
40、IC, I meter reading (that exists when there is no transistor in the test socket) can be accomplished by using one or more of the following techniques: 4.3.3.1 The ICreI of the test socket itself can be largely eliminated by installing a piece of sheet metal (used as an electrostatic shield) between
41、the base and the collector guide tubes and soldering it to the shield guide tube (which is grounded). This electro- static shield should extend as near as practical to the top of the test socket (the header plane)and should extend sufficiently far in the other three directions to appreciably re- duc
42、e the direct capacitance between the base and the collector guide tubes. 4.3.3.2 A dc bias can be applied to the detector to cancel the residual IC,I meter reading. 4.3.3.3 The mechanical zero adjustment of the panel meter can be used to “zero out” the residual reading. This technique will not work
43、where the residual IC, 1 meter reading is larger than the capability of the mechanical zero or where the panel meter is used for more than one range. 4.4 Socket Connections 4.4.1 Emitter The emitter shall be AC grounded. See Figure 3. 4.4.2 Base The base shall be shorted to ground through a current
44、sampling resistor, R,. 4.4.3 Collector The collector shall be fed with a constant RF voltage of the required measurement frequency. This voltage shall be low enough that doubling it will not change the IC, 1 reading by more than one-half of the required overall accuracy of measurement. This insures
45、that the transistor will be tested under small-signal conditions. 4.4.4 Shield The disposition of the shield lead (if any) shall reflect the transistors intended use. The shield lead will almost always be grounded. A three-lead transistor having a floating case shall not have its case grounded (thro
46、ugh a ground clamp) during the IC,I measurement unless it is in- tended to be used that way. RS.340 Page 8 4.5 METER CIRCUITRY 4.5.1 Current-Sampling Resistor The value of the current-sampling resistor, R, shall be low enough that doubling it will not in- crease the IC!, 1 reading by more than one-h
47、alf of the required overall accuracy of measure- ment. This condition can be met by satisfying the following inequality. R A (p+ 1) re+rbb s 200 P where Rs = current-sampling resistor p = lhfe I at the frequency of measurement kT re= _ = 25.1 mV at 250C qlE IE rbb = base-spreading resistance p = ove
48、rall measurement accuracy in percent The value of IC,eI is directly proportional to the magnitude of the sampling voltage, V, across the current-sampling resistor, R,. Icre I = Ivrs I w Rs l”ceI This equation will yield the sensitivity requirement for the remainder of the metering circuitry. 4.5.2 T
49、uned Amplifier A typical IC, I test will have a sampling voltage of a few microvolts per picofarad. It is neces- sary to use an amplifier to amplify this one or two microvolt signal to the level necessary to drive a detector and panel meter. A tuned rather than a wide-band amplifier is used to insure that any harmonics generated due to the nonlinearity of the transistors base-collector junction will not affect the &.I reading. A series L-C circuit connected across the current-sampling resistor, with the tuned amplifier being dr
