Overview

This part of IEC 62575 specifies the test procedures and general requirements for radio frequency (RF) bulk acoustic wave (BAW) filters of assessed quality, using either the capability approval or qualification approval procedure. The quartz filters standardized in the IEC 60368 series of standards are not within the scope of this standard. RF BAW filters are widely used in mobile radio applications today. Although RF BAW filters satisfy different requirements, they can for the most part be classified into a few basic classes. Standard specifications according to the IEC 62575 series of standards, as well as national specifications or design specifications issued by manufacturers, indicate the available combinations of nominal frequency, pass bandwidth, ripple, form factor, termination impedance, and so on. These specifications are prepared to cover a wide range of RF BAW filters with standardized characteristics. It cannot be stressed enough that the user should select RF BAW filters with standardized characteristics whenever possible, even though the use of standard filters may result in minor changes to the user's circuit. This is especially true for the selection of the nominal frequency. This standard responds to the desire generally expressed by users and manufacturers for a guide to the application of RF BAW filters that will enable the benefits of these filters to be exploited in the best possible way. For this reason, general and basic characteristics are explained in this part of IEC 62575. It is not the purpose of this standard to explain theory or to attempt to address all possibilities that may arise under practical circumstances. This standard draws attention to some basic issues that the user should consider before ordering an RF BAW filter for a new application. Such an approach is intended to protect the user from an unsatisfactory result. In the "Terms" clause, essential general terms and definitions are explained which are necessary for the application of the standard. The bulk acoustic wave (BAW) is an acoustic wave that propagates between the top and bottom of a piezoelectric structure, passing through the entire thickness of the piezoelectric solid. The wave is excited by metal electrodes placed on both sides of the piezoelectric layer. The volume wave filter (BAW filter) is a filter based on acoustic volume waves, usually generated by a pair of electrodes, propagating along a thin film thickness direction. The clause "Preferred design and characteristics" includes rated frequencies, operating temperature ranges, climatic category, severity level for continuous shock testing, and severity level for vibration testing. In the "Quality assessment procedures" clause, two procedures are provided for the recognition of BAW filters with assessed quality, capability approval and qualification approval. The capability or qualification approval procedure shall be applied for the approval of BAW filters. These procedures correspond to those specified in IEC QC 001001 and IEC QC 001002-3. Capability approval shall be used when structurally similar BAW filters are manufactured based on common design rules using a set of the same procedures. Qualification approval shall be applied to components manufactured according to a general design guideline and an established manufacturing process and conforming to a published detail specification. The clause "Test and measurement procedures" explains the test and measurement conditions, the dimensions and gauge procedures, and the electrical test procedures, which are the measurement of insertion loss, measurement of reflection loss, measurement of intermodulation distortion, measurement of insertion loss characteristics at specified termination impedance and normal climate, and measurement procedures for balanced filters. As a rule insertion loss, reflection loss and intermodulation distortion are measured for balanced BAW filters using the procedures described in the previous sections. It should be noted that a filter is a two-port component; for measurement purposes, it is convenient to treat a filter with balanced connections on the input and output sides as a four-port component, and a filter with balanced connections on one side and an unbalanced connection on the other side as a three-port component. It is therefore recommended that a multi-port network analyzer be used. Other clauses describe mechanical and environmental test procedures and the endurance test procedures. When testing aging (non-destructive), the HF-BAW filter shall be stored at (85 ± 2) °C for an uninterrupted period of 30 days, unless otherwise specified in the detail specification. After the test period, the filter shall be stored at normal climate for testing until thermal equilibrium is reached. The specified tests shall be performed and the results of the final measurements shall be within the limits specified in the detail specification. The responsible committee is DKE/K 642 "Piezoelektrische Bauteile zur Frequenzstabilisierung und -selektion" ("Piezoelectric and dielectric devices for frequency control and selection") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE.

Document: references other documents

Responsible national committee

DKE/K 642 - Piezoelektrische Bauteile zur Frequenzstabilisierung und -selektion