Overview

This part of IEC 61837 deals with standard outlines and terminal lead connections as they apply to SMDs for frequency control and selection in metal enclosures and is based on IEC 61240 which standardized layout rules of outline drawings of the surface-mounted devices. The surface mount device packages are made of metal with their moulded terminals based on the descriptive marking system for semiconductor packages. The SMD packages described in this part of IEC 61837 are in all cases special surface mount packages. Therefore, the following identifier is used: SMS (Surface-Mounted, Special). The dimensions given in this part of IEC 61837 apply to all finished SMD components for frequency stabilization and selection. Only the dimensions that meet the requirements of IEC 61240 are given. The standard differs from the previous edition as follows: - The outline drawing is defined as one set of drawings consisting of four views: the view from above, the front view, the view from the right, and the view from below. The view from the right was drawn optionally in the previous edition. - The height of package is eliminated in this edition; instead total height is expressed by the symbol letter G or G with a subscript number. - The dimensions of terminal lead spacing are shown by the centre position of the terminal leads and its basic value e is 2.54×n mm (n is an integer) and 1,27×n mm for package dimensions smaller than 6 mm. If the terminal lead spacing is not a multiple of the basic value, then e shall be specified with an additional subscript number. If there are plural spacing values, the subscript number is followed by a hyphen and number. - In terminal land areas, the lengths of each terminal pad are now expressed with maximum values for consumer's convenience. They were expressed as minimum values in the previous edition of IEC 61837-3. - If there are plural identical enclosures with different height, each enclosure is expressed by a dash (/) and a two-digit number after the basic type name. The identity references are given in the table of the sheet. - The configurations of the enclosures were revised as shown in Table 1. 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