ECA EIA-198-1-F-2002 Ceramic Dielectric Capacitors Classes I II III and IV - Part I Characteristics and Requirements (Revision of EIA-198-1-E)《I、II、III和IV类陶瓷电介质电容器-第I部分 特性和要求 修改版EI.pdf
《ECA EIA-198-1-F-2002 Ceramic Dielectric Capacitors Classes I II III and IV - Part I Characteristics and Requirements (Revision of EIA-198-1-E)《I、II、III和IV类陶瓷电介质电容器-第I部分 特性和要求 修改版EI.pdf》由会员分享,可在线阅读,更多相关《ECA EIA-198-1-F-2002 Ceramic Dielectric Capacitors Classes I II III and IV - Part I Characteristics and Requirements (Revision of EIA-198-1-E)《I、II、III和IV类陶瓷电介质电容器-第I部分 特性和要求 修改版EI.pdf(26页珍藏版)》请在麦多课文档分享上搜索。
1、 EIA STANDARD Ceramic Dielectric Capacitors Classes I, II, III and IV Part I: Characteristics and Requirements EIA-198-1-F (Revision of EIA-198-1-E) NOVEMBER 2002 ELECTRONIC COMPONENTS, ASSEMBLIES EIA-198-B-1: EIA-198-B-2; EIA-198-B-3A and EIA-198-C, EIA-198-D, and EIA-198-E have been incorporated i
2、nto EIA-198-F. EIA-198-1-F vi This page left blank. EIA-198-1-F Page 1 EIA-198-1-F of this standard provides means to characterize ceramic capacitors electrically and mechanically by use of type designators. In addition, this section outlines dielectric classifications, marking specifications and te
3、st sequences. 1.1 Dielectric classification There are four major classifications of ceramic dielectrics, with class I being the least variable with temperature and voltage, and class IV being the most variable. Class I dielectrics are typically used in applications requiring the tightest tolerance.
4、1.1.1 Class I Components of this type are temperature compensating ceramic dielectrics, fixed capacitors of a type suited for resonant circuit applications or other applications where high Q and stability of capacitance characteristics are required. (See table 1.) 1.1.2 Class II Components of this c
5、lassification are fixed, ceramic dielectric capacitors of a type suited for bypass and decoupling application or for frequency discriminating circuits where Q and stability of capacitance characteristics are not of major importance. This classification is further defined as those capacitors having t
6、emperature characteristics A through S (see table 3). Class II ceramic dielectrics exhibit a predictable change with time and voltage. Compensation for the aging effect is made by referencing capacitance limits to a future time deemed to be most useful to the buyer; 1,000 hours is normally chosen, b
7、ut other arrangements may be negotiated between the buyer and seller. Voltage will also cause a temporary capacitance change, and the test sequence should be such that capacitance measurements are not affected by previous voltage tests. The aging rate of a dielectric is essentially constant over man
8、y decades of time, i.e., 10 h to 100 h, 100 h to 1,000 h, 1,000 h to 10,000 h, etc., when measured from the time of the last heat of depolarization in manufacture. Restoration of the original capacitance at time of manufacture will occur on heating to 150 oC for one hour, after which normal aging wi
9、ll again commence. Capacitors measured prior to 24 hours may exhibit temporarily high capacitance values that will age downward. 1.1.3 Class III Components herein standardized are fixed ceramic dielectric capacitors of a type specifically suited for use in electronic circuits for bypass, decoupling
10、or other applications in which dielectric losses, high insulation resistance and capacitance stability are not of major consideration. This classification is identical to that of class II, except that it is restricted to those capacitors having temperature characteristics T through V (table 3). 1.1.
11、4 Class IV This classification is restricted to those components utilizing reduced titanate or barrier layer type construction,. While basically fitting the descriptions of class II and class III, certain other electrical differences can be noted, as described in EIA-198-3-F of this specification. 1
12、.2 Mechanical classifications 1.2.1 Unleaded multilayer ceramic capacitors Unleaded ceramic chip capacitors are available in a variety of physical sizes and shapes lending themselves to a wide variety of specialized applications. Generally, the unit consists of an unencapsulated fired capacitor elem
13、ent with metallized terminations. A range of end metallizations is available to match the variety of possible bonding techniques. The absence of leads and any encapsulating material makes them extremely space efficient and well suited to hybrid circuit use in decoupling, bypassing, timing, tuning, e
14、tc. 1 Scope EIA-198-1-F Page 2 Generally, chip capacitors are available in dielectric classifications, I, II and III, suiting them for a wide range of hybrid applications where space is a prime consideration. The absence of lead inductance enables operation at considerably higher frequencies than co
15、mparable leaded units of the same capacitance value. Since these units are unencapsulated, they require an environment that minimizes the effects of humidity and contamination. Care must be taken to ensure that units are kept free or cleaned of ionizable residues deposited by handling or fluxing dur
16、ing manufacture. Care must also be exercised in the selection of substrate materials to minimize possible stresses due to differences in thermal expansion coefficients. Soldering methods, especially wave soldering, can cause thermal shock failures in unleaded surface-mounted capacitors. Susceptibili
17、ty to cracks caused by substrate thermal expansion, flexure, and thermal shock increases with body size. CC1210 bodies and larger, and CC0402 bodies and smaller, ceramic capacitor arrays, and any chips thicker than 1.7mm in height are generally not recommended for wave solder assembly, especially on
18、 the bottom of PC boards. 1.2.2 Leaded multilayer ceramic capacitors Leaded multilayer ceramics are available in both radial and axial lead configurations. Finished units consist of a multilayer chip attached to leads or lead frames and encapsulated with a protective environmental barrier. A large r
19、ange of capacitance values, case sizes and configurations are available which are suitable for manual or automatic insertion. Both axial and radial units are available in dielectric classifications I, II and III. These components are generally used in conventional printed circuit board (PCB) constru
20、ction at lower than ultrahigh frequencies (UHF). Typical applications include decoupling, bypassing, timing, filtering and tuning. The encapsulation of these units forms an environment barrier that allows unprotected operation in a variety of circuit environments. 1.2.3 Disk and tubular ceramic capa
21、citors Single layer disk, plates, and tubular capacitors are available in a variety of axial and/or radial styles. Units consist of a single layer of ceramic dielectric separating two electrodes. The entire assembly is encapsulated with a protective material. Typically, units are available lead tape
22、d and reeled for automatic insertion or bulk packed for manual assembly. Units available in dielectric classifications I, II, III and IV are typically used in conventional PCB assembly, in decoupling, bypassing, timing, filtering and tuning applications. Since their single layer construction (classe
23、s I, II, and III) can allow for higher voltage ratings than most common multilayer devices, these units have been preferred for applications where large working voltages are expected. 1.3 Type designation The type designation shall be in the form of the following examples: EIA designation_ Body code
24、 TC code Capacitance code_ Tolerance code_ Voltage code CC CC 025 1206 COG X7R 150 103 J K 500 101 1.3.1 EIA designator and body code The style designator consists of the two letter symbol “CC” (unless otherwise specified) followed by a two (2), three (3) or four (4) digit numeric code identifying s
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