Transistor mounting clamp assembly

• US 5,439,398 A
• Filed: 12/10/1992
• Issued: 08/08/1995
• Est. Priority Date: 12/10/1992
• Status: Expired due to Term

• Current Assignee: Radio Frequency Systems Incorporated (Amphenol Corporation)
• Original Assignee: Radio Frequency Systems Incorporated (Amphenol Corporation)
• Inventors: Smith, Robert P., Testa, Martina B.
• Primary Examiner(s): Paumen, Gary F.
• Application Number:
  US07/989,038
• Time in Patent Office: 971 Days
• Field of Search: 439/801, 439/431, 439/883, 411/237, 411/366, 411/187, 411/185
• US Class Current: 439/801
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01R 12/57 surface mounting terminals
• CPC Class Codes: H01R 4/38 utilising a clamping member acted on by screw or nut H01R4/50 takes precedence
• CPC Class Codes: H05K 2201/10409 Screws
• CPC Class Codes: H05K 3/325 by abutting or pinching, i.e. without alloying process; mechanical auxiliary parts therefor adaptations of leads inserted in holes for press-fit connections H05K3/308

Abstract

A transistor mounting clamp assembly for ensuring reliable electrical connection of a power transistor electrical connector tab (typically the collector tab) to a metallized portion of an associated printed circuit board. The transistor mounting clamp assembly comprises a top and bottom clamp dimensioned for sandwiching therebetween the transistor tab. The clamp assembly uses a machine screw and associated Belleville washer for maintaining this urging relationship even when the components expand and contract. The bottom clamp preferably has a stepped region or other surface discontinuity for securing the connector tab thereto. The clamp assembly further comprises an extending tab which is secured to the top clamp and which has a second region for providing electrical connection to the metallized portion of the printed circuit board by soldering, or other means. The overall transistor mounting clamp is able to withstand thermal expansion and contraction associated with intermittent operation of the associated power transistor and is also able to make reliable electrical connection to associated tabs of matching network elements typically used in transistor amplifier applications associated with ultra-high frequency and microwave operations. The clamp assembly can also be used to secure electrical connector tabs of other typically high-powered devices, and thus is not limited to power transistor applications.

Claims

1. A transistor mounting clamp assembly for electrically connecting an electrical connector tab of a power transistor to a metallized portion of an associated printed circuit board, comprising:

A) a top clamp having a first surface dimensioned for engagement with the connector tab of the transistor;

B) a bottom clamp having a first surface dimensioned for engagement with the top clamp first surface and with the connector tab positioned therebetween;

C) means for mechanically urging the top clamp and bottom clamp together so as to sandwich the transistor connector tab between said first surfaces; and

D) means for electrically connecting the clamp assembly to the metallized portion of the associated printed circuit board.

2. A transistor mounting clamp assembly as defined in claim 1, wherein the means for mechanically urging the top clamp and bottom clamp together so as to sandwich the connector tab therebetween, comprises a machine screw and a means for absorbing mechanical movement of the top clamp and bottom clamp, wherein the top clamp and bottom clamp each have a bore and wherein the machine screw passes through both bores and further wherein the bottom clamp bore is threaded for mechanical engagement by the machine screw.

3. A transistor mounting clamp assembly as defined in claim 2, wherein the means for absorbing mechanical movement of the top clamp and bottom clamp comprises a Belleville washer positioned between the machine screw and the means for electrically connecting the clamp assembly to the metallized portion of the printed circuit board.

4. A transistor mounting clamp assembly as defined in claim 2, wherein the means for absorbing mechanical movement of the top clamp and bottom clamp comprises a lock washer positioned between the machine screw and the means for electrically connecting the clamp assembly to the metallized portion of the printed circuit board.

5. A transistor mounting clamp assembly as defined in claim 3, wherein the top clamp first surface is cone-shaped for engagement with the bottom clamp, wherein the bottom clamp first surface is concavely shaped for matching engagement therewith.

6. A transistor mounting clamp assembly as defined in claim 5, wherein the bottom clamp first surface has at least one stepped region for wedging engagement with the connector tab.

7. A transistor mounting clamp assembly as defined in claim 6, wherein the top clamp and bottom clamp are each hexagonal in shape.

8. A transistor mounting clamp assembly as defined in claim 7, wherein the top clamp and bottom clamp are dimensioned for engagement with at least one additional electrical connector tab of at least one additional electronic component.

9. A transistor mounting clamp assembly as defined in claim 8, wherein the means for electrically connecting the clamp assembly to the metallized portion of the associated printed circuit board comprises an extending tab dimensioned at one region thereof for mechanical and electrical engagement with the top clamp, the extending tab having a second region dimensioned for engagement with the metallized portion of the printed circuit board for forming an electrical connection therewith.

10. A transistor mounting clamp assembly as defined in claim 9, wherein the extending tab is formed from copper and wherein the metallized portion of the printed circuit board is fabricated from copper, thereby forming a union between the extending tab and the metallized portion of the printed circuit board with similar metals so as to minimize differential thermal heating therebetween.

11. A transistor mounting clamp assembly as defined in claim 10, wherein the transistor has a metal flange forming a portion thereof, said flange dimensioned for mechanical mounting to a heat sink.

12. A transistor mounting clamp assembly as defined in claim 10, wherein the electrical connector tabs have substantially different thicknesses, and wherein the clamp assembly further comprises at least one shim for placement adjacent each electrical connector tab that has a thickness substantially less than the thickest tab, each such shim having a thickness, when combined with the thickness of the adjacent tab, that is approximately the same as the thickness of the thickest tab.

13. A transistor mounting clamp assembly as defined in claim 8, wherein the electrical connector tabs have substantially different thicknesses, and wherein the clamp assembly further comprises at least one shim for placement adjacent each electrical connector tab that has a thickness substantially less than the thickest tab, each such shim having a thickness, when combined with the thickness of the adjacent tab, that is approximately the same as the thickness of the thickest tab.

14. A transistor mounting clamp assembly as defined in claim 1, wherein the top clamp and bottom clamp are dimensioned for engagement with at least one additional electrical connector tab of at least one additional electronic component.

15. A transistor mounting clamp assembly as defined in claim 1, wherein the electrical connector tab secured by the clamp assembly is the collector tab of the power transistor.

16. A transistor mounting clamp assembly as defined in claim 1, wherein the bottom clamp has a second surface opposed from its first surface and wherein the clamp assembly is associated with a heat sink, further wherein the clamp assembly comprises a shoulder washer having a top and bottom surface, the top surface dimensioned for engagement with the second surface of the bottom clamp, and where the bottom surface is dimensioned for engagement with the heat sink.

17. A transistor mounting clamp assembly as defined in claim 16, further comprising means for receipt of DC electrical power.

18. A transistor mounting clamp assembly as defined in claim 1, further comprising means for receipt of DC electrical power.

19. A transistor mounting clamp assembly as defined in claim 1, wherein the bottom clamp first surface includes discontinuities that project toward the first surface of the top clamp.

20. A transistor mounting clamp assembly as defined in claim 1, wherein the top clamp first surface includes discontinuities that project toward the first surface of the bottom clamp.

21. A transistor mounting clamp assembly as defined in claim 1, wherein the top clamp and bottom clamp are each T-shaped and wherein three electrical connector tabs are securable between the first surface of the top clamp and bottom clamp.

22. A mounting clamp assembly for electrically connecting an electrical connector tab integrally forming part of an electrical device to another area, comprising:

A) a top damp having a first surface in engagement with the connector tab of the electrical device;

B) a bottom clamp having a first surface in engagement with the top clamp first surface and with the connector tab positioned therebetween;

C) means mechanically urging the top clamp and bottom clamp together so as to sandwich the connector tab between said first surfaces; and

D) means for electrically connecting the clamp assembly to another area.

23. A mounting clamp assembly as defined in claim 22, wherein the means mechanically urging the top clamp and bottom clamp together so as to sandwich the connector tab therebetween, comprises a machine screw and a means for absorbing mechanical movement of the top clamp and bottom clamp, wherein the top clamp and bottom clamp each have a bore and wherein the machine screw passes through both bores and further wherein the bottom clamp bore is threaded for mechanical engagement by the machine screw.

24. A mounting clamp assembly as defined in claim 23, wherein the means for absorbing mechanical movement of the top clamp and bottom clamp comprises a Belleville washer positioned between the machine screw and the means for electrically connecting the clamp assembly to another area.

25. A mounting clamp assembly as defined in claim 24, wherein the top clamp first surface is cone-shaped for engagement with the bottom clamp, wherein the bottom clamp first surface is concavely shaped for matching engagement therewith.

26. A mounting clamp assembly as defined in claim 25, wherein the bottom clamp first surface has at least one stepped region for wedging engagement with the connector tab.

27. A mounting clamp assembly as defined in claim 22, wherein the top clamp and bottom clamp are each rotary symmetric in shape.

28. A mounting clamp assembly as defined in claim 22, wherein the top clamp and bottom clamp are in engagement with at least one additional electrical connector tab of at least one additional electronic component.

29. A mounting clamp assembly as defined in claim 28, wherein the means for electrically connecting the clamp assembly to another area comprises an extending tab dimensioned at one region thereof for mechanical and electrical engagement with the top clamp, the extending tab having a second region dimensioned for engagement with said other area.

30. A mounting clamp assembly as defined in claim 29, wherein the other area is a metallized portion of an associated printed circuit board.

31. A mounting clamp assembly as defined in claim 28, wherein the electrical connector tabs have substantially different thicknesses, and wherein the clamp assembly further comprises at least one shim for placement adjacent each electrical connector tab that has a thickness substantially less than the thickest tab, each such shim having a thickness, when combined with the thickness of the adjacent tab, that is approximately the same as the thickness of the thickest tab.

32. A mounting clamp assembly as defined in claim 31, wherein each shim is fabricated from the same material as the connector tab to which it is placed adjacent thereto, and wherein each shim is gold plated.

33. A mounting clamp assembly as defined in claim 26, wherein the top clamp and bottom clamp are in engagement with at least one additional electrical connector tab of at least one additional electronic component.

34. A mounting clamp assembly as defined in claim 22, wherein the bottom clamp has a second surface opposed from its first surface and wherein the clamp assembly is associated with a heat sink, further wherein the clamp assembly comprises a shoulder washer having a top and bottom surface, the top surface in engagement with the second surface of the bottom clamp, and where the bottom surface is in engagement with the heat sink.

35. A mounting clamp assembly as defined in claim 22, further comprising means for receipt of DC electrical power.

36. A mounting clamp assembly as defined in claim 22, wherein the bottom clamp first surface includes discontinuities that project toward the first surface of the top clamp.

37. A mounting clamp assembly as defined in claim 22, wherein the top clamp first surface includes discontinuities that project toward the first surface of the bottom clamp.

38. A mounting clamp assembly as defined in claim 22, wherein the top clamp and bottom clamp first surfaces are gold plated.