Thyristor Semiconductor Products Page 38 Thyristor

2014 Littelfuse, Inc. Specifications are subject to change without notice. Revised: 12/14/14 Teccor brand Thyristors AN1004 Mounting and Handling of Semiconductor Devices Proper mounting and handling of semiconductor devices, particularly those used in power applications, is an important, yet sometimes overlooked, consideration in the assembly of electronic systems. Power devices need adequate heat dissipation to increase operating life and reliability and allow the device to operate within manufacturers' specifications. Also, in order to avoid damage to the semiconductor chip or internal assembly, the devices should not be abused during assembly. Very often, device failures can be attributed directly to a heat sinking or assembly damage problem. The information in this application note guides the semi- conductor user in the proper use of Littelfuse devices, particularly the popular and versatile TO-220 and TO-218 epoxy packages. Contact the Littelfuse Applications Engineering Group for further details or suggestions on use of Littelfuse devices. Standard Lead Forms Littelfuse encourages users to allow factory production of all lead and tab form options. Littelfuse has the automated machinery and expertise to produce pre-formed parts at minimum risk to the device and with greater convenience section of this catalog for a complete list of readily available lead form options. Contact Littelfuse for information regarding custom lead form designs. Lead Bending Method Leads may be bent easily and to any desired angle, for TO-218 package) away from the package body with a 1.5 times lead thickness rule. DO-15 device leads may be should be held firmly between the package body and the bend so that strain on the leads is not transmitted to the package body, as shown in Figure AN1004.2. Also, leads should be held firmly when trimming length. Incorrect (A) (B) Correct Figure AN1004.2 Lead Bending Method When bending leads in the plane of the leads (spreading), bend only the narrow part. Sharp angle bends should be done only once as repetitive bending will fatigue and break the leads. Introduction Lead Forming - Typical Configurations A variety of mounting configurations are possible with Littelfuse power semiconductor TO-92, DO-15, and TO- 220 packages, depending upon such factors as power requirements, heat sinking, available space, and cost considerations. Figure AN1004.1 shows typical examples and basic design rules. A B C D SOCKET TYPE MOUNTING: Useful in applications for testing or where frequent removal is necessary. Excellent selection of socket products available from companies such as Molex. Figure AN1004.1 Component Mounting These are suitable only for vibration-free environments and low-power, free-air applications. For best results, the device should be in a vertical position for maximum heat dissipation from convection currents.

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