IEC 61240 pdf download

IEC 61240 pdf download.Piezoelectric devices – Preparation of outline drawings of surface-mounted devices (SMD) for frequency control and selection – General rules
1 Scope
This International Standard sets out general rules for drawing all dimensional and geometrical characteristics of a surface-mounted piezoelectric device package (referred to in this document as SMD) in order to ensure mechanical inter-changeability of all outline drawings of the SMDs for frequency control and selection.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 601 91 -6, Mechanical standardization of semiconductor devices – Part 6: General rules for the preparation of outline drawings of surface mounted semiconductor device packages
3 Classification of SMD
The SMD piezoelectric devices are classified into three types of packages depending on the structure of the terminal leads. a) Leaded type: the folded ends of the terminal leads are turned away from the body. NOTE 1 The package of the pin lead type is compatible with the socket. This is defined in the description of the leaded type. b) Folded-leads type: the folded ends of the terminal lead are turned towards the body. NOTE 2 The supporter with a board is defined in the description of this folded lead type. c) Leadless type: terminal pads only are present on the body instead of terminal leads. A proper combination of these options should be selected.
4 Title of the outline drawing
The title of the outline drawing shall imply the main package material (e.g. metal, plastic, glass, ceramic), the sealing procedure, number of terminals and the type of SMD, as shown in Examples 1 , 2 and 3 1 .
5 Composition of the outline drawing
5.1 Elements of outline drawings The outline drawing of an SMD shall be composed of five elements: the drawings from four views in the third-angle projection, the table of detailed dimensions, the actual size sketch, the drawing of terminal land areas and the terminal lead details. These sample formats are shown in Examples 1 , 2, and 3. 5.2 Outline drawing The outline drawing with dimensional symbols shall be executed in the third-angle projection. Basically, one set of outline drawings consists of the view from above, the front view, the view from the right, and the view from below. In square type enclosure and cylindrical type enclosure, the view from the right can be omitted. 5.3 Table of detailed dimensions The dimensions shall be given in millimetres and are required only where the letter X is shown in the table. 5.4 Actual size sketch The actual size sketch means a drawing of the view from above with the real size outer dimensions. 5.5 Drawing of terminal land areas The drawing of terminal land areas which is defined in Clause 7 shall be adapted to the connecting terminal leads on the printed circuit boards, alumina substrates, etc. 5.6 Terminal lead details The terminal lead details shall be shown in accordance with IEC 601 91 -6 (see Figure 1 ).
6 Requirements for terminal leads
6.1 The dimensions of terminal lead spacing shall be 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. 6.2 In the view from above of SMD, the lower lead from the left end shall be designated as terminal lead number 1 . The subsequent lead numbers shall be designated as 2 to n, with the terminals following counter-clockwise. 6.3 The number 1 terminal lead shall be indicated by a corner notch or by a dotted expression on the top side. If there is a requirement to indicate the number 1 terminal on bottom side, the land area of the number 1 terminal can be designed in different size from others.