Impedance matching external component connections with uncompensated leads
View Patent ↗In one aspect, an electronic assembly includes an interconnection substrate, a component, and a discontinuity compensator. The interconnection substrate includes a signal conductor and a ground conductor. The component includes a device having a signal line and a ground conductor, a package, and a signal lead. The signal lead is electrically coupled to an internal signal path of the package and has an external portion extending from the package to the signal conductor of the interconnection substrate. The discontinuity compensator electrically couples a ground path of the package to the ground conductor of the interconnection substrate. The discontinuity compensator includes an electrically conducting planar surface that is oriented in a plane intersecting the interconnection substrate and forms with at least a substantial part of the external portion of the signal lead a transmission line structure having an impedance substantially matching the nominal impedance over the specified bandwidth.
1. An electronic assembly, comprising:
an interconnection substrate comprising a signal conductor and a ground conductor;
a component comprising
a device having a signal line and a ground conductor,
a package containing the device, an internal signal path electrically coupled to the signal line of the device and having a nominal impedance over a specified bandwidth, and a ground path electrically coupled to the ground conductor of the device, and
a signal lead electrically coupled to the internal signal path and having an external portion extending from the package to the signal conductor of the interconnection substrate; and
a discontinuity compensator electrically coupling the ground path of the package to the ground conductor of the interconnection substrate and comprising an electrically conducting planar surface oriented in a plane intersecting the interconnection substrate and forming with at least a substantial part of the external portion of the signal lead a transmission line structure having an impedance substantially matching the nominal impedance over the specified bandwidth.
2. The electronic assembly of claim 1 , wherein the discontinuity compensator has a flange bonded to an exterior area of the package.
3. The electronic assembly of claim 1 , wherein the discontinuity compensator has a flange bonded to the ground conductor of the interconnection substrate.
4. The electronic assembly of claim 1 , wherein the discontinuity compensator has a protrusion extending into a hole in the interconnection substrate.
5. The electronic assembly of claim 1 , wherein the signal lead bends in a bend plane intersecting the interconnection substrate, and the electrically conducting surface of the discontinuity compensator is substantially parallel to the bend plane.
6. The electronic assembly of claim 1 , further comprising an electrically insulating dielectric material between the electrically conducting surface of the discontinuity compensator and the signal lead.
7. The electronic assembly of claim 1 , wherein between the package and the interconnection substrate the discontinuity compensator is detached from the signal lead.
8. The electronic assembly of claim 1 , wherein the signal lead has a circular cross section.
9. The electronic assembly of claim 1 , wherein the package is a transistor outline (TO) can package.
10. The electronic assembly of claim 2 , wherein the flange is soldered to the exterior area of the package.
11. The electronic assembly of claim 5 , wherein:
the component comprises a second signal lead electrically coupled to a second internal signal path of the package, having an external portion extending from the package to a second signal conductor of the interconnection substrate, and bending in a second bend plane; and
the discontinuity compensator additionally comprises a second electrically conducting planar surface substantially parallel to the second bend plane and forming with at least a substantial part of the external portion of the second signal lead a transmission line structure having an impedance substantially matching the nominal impedance over the specified bandwidth.
12. The electronic assembly of claim 6 , wherein the dielectric material is attached to the electrically conducting surface of the discontinuity compensator.
13. A method of making an electronic assembly, comprising:
(a) providing an interconnection substrate comprising a signal conductor and a ground conductor;
(b) providing a component comprising
a device having a signal line and a ground conductor,
a package containing the device, an internal signal path electrically coupled to the signal line of the device and having a nominal impedance over a specified bandwidth, and a ground path electrically coupled to the ground conductor of the device, and
a signal lead electrically coupled to the internal signal path and having an external portion extending from the package;
(c) electrically connecting the external portion of the signal lead to the signal conductor of the interconnection substrate; and
(d) after (c), attaching to the ground path of the package and to the ground conductor of the interconnection substrate a discontinuity compensator comprising an electrically conducting surface that forms with at least a substantial part of the external portion of the signal lead a transmission line structure having an impedance substantially matching the nominal impedance over the specified bandwidth.
14. The method of claim 13 , wherein the discontinuity compensator has a flange, and (d) comprises bonding the flange to an exterior area of the package.
15. The method of claim 13 , wherein the discontinuity compensator has a flange, and (d) comprises bonding the flange to the ground conductor of the interconnection substrate.
16. The method of claim 13 , wherein the discontinuity compensator has a protrusion, and (d) comprises extending the protrusion into a hole in the interconnection substrate.
17. The method of claim 13 , wherein the discontinuity compensator comprises an electrically conducting planar surface, and (d) comprises positioning the electrically conducting planar surface near the external portion of the signal lead and oriented in a plane intersecting the interconnection substrate.
18. The method of claim 13 , wherein (c) comprises bending the signal lead in a bend plane intersecting the interconnection substrate, and (d) comprises positioning the electrically conducting planar surface near the signal lead and substantially parallel to the bend plane.
19. The method of claim 14 , wherein (d) comprises solder bonding the flange to the exterior area of the package.
20. The method of claim 18 , wherein:
the component comprises a second signal lead electrically coupled to a second internal signal path of the package and having an external portion extending from the package, and (c) comprises electrically connecting the external portion of the second signal lead to a second signal conductor of the interconnection substrate and bending the second signal lead in a second bend plane; and
the discontinuity compensator additionally comprises a second electrically conducting planar surface, and (d) comprises positioning the second electrically conducting planar surface near the second signal lead and substantially parallel to the second bend plane to form with the external portion of the second signal lead at least part of a second transmission line structure having an impedance substantially matching the nominal impedance over the specified bandwidth.