Components having voltage switchable dielectric materials
Various aspects provide for structures and devices to protect against spurious electrical events (e.g., electrostatic discharge). Some embodiments incorporate a voltage switchable dielectric material (VSDM) bridging a gap between two conductive pads. Normally insulating, the VSDM may conduct current from one pad to the other during a spurious electrical event (e.g., shunting current to ground). Some aspects include gaps having a gap width that is greater than 50% of a spacing between electrical leads connected to the pads. Some devices include single layers of VSDM. Some devices include multiple layers of VSDM. Various devices may be designed to increase a ratio of active volume (of VSDM) to inactive volume.
1. A device incorporating a voltage switchable dielectric material (VSDM), the device comprising:
first and second conductive leads separated by a package spacing; the first lead electrically connected to a first conductive pad;
the second lead electrically connected to a second conductive pad;
the first and second conductive pads separated by a first gap, the first gap having a first gap width greater than 50% of the package spacing;
a first VSDM bridging the first gap and connecting the first and second conductive pads;
a third conductive pad electrically connected to the first lead;
a fourth conductive pad electrically connected to the second lead;
the third and fourth conductive pads separated by a second gap; and
a second VSDM connecting the first and second conductive pads via the second gap.
2. The device of claim 1 , wherein the first gap width is greater than the package spacing.
3. The device of claim 1 , wherein the first gap width is greater than two times the package spacing.
4. The device of claim 1 , wherein the first gap width is greater than five times the package spacing.
5. The device of claim 1 , wherein the first gap width is greater than ten times the package spacing.
6. The device of claim 1 ,
wherein the second VSDM has a different composition than the first VSDM.
7. The device of claim 1 , wherein the device includes a multilayer stack, the first and second VSDM are disposed on different layers of the multilayer stack, and the conductive pads are electrically connected to their respective leads by conductive vias through the multilayer stack.
8. The device of claim 1 , wherein the first and second VSDM have different thicknesses.
9. The device of claim 1 , wherein the first and second VSDM have different electrical properties.
10. The device of claim 1 , wherein the first and second gaps have different gap widths.
11. The device of claim 1 , wherein the first and second gaps have different lengths.
12. The device of claim 1 , wherein the package spacing is between 200 microns and 8,000 microns.
13. The device of claim 1 , wherein the package spacing corresponds to a distance between electrical connection points associated with any of an EIA 0201, 0402, and 0603 device.
14. The device of claim 1 , wherein the first gap width is between 500 and 5000 microns.
15. The device of claim 1 , wherein any of the pads, leads, and first gap is fabricated using lithography.
16. The device of claim 15 , wherein the gap is characterized by a tolerance on a distance between the pads that is within 20% of the value of the distance.
17. The device of claim 16 , wherein the tolerance is within 10%.
18. The device of claim 1 , wherein the first gap is between 10 and 100 microns long.
19. The device of claim 1 , further comprising a dielectric substrate, wherein the first VSDM is disposed as a first layer on the dielectric substrate and the first and second conductive pads are disposed as a second layer on the first VSDM.
20. The device of claim 19 , wherein the substrate includes a layer of prepreg, and the conductive pads include copper.
21. The device of claim 1 , further comprising a third conductive lead electrically connected to a fifth conductive pad, the fifth conductive pad attached to the first VSDM and separated from any of the first and second conductive pads by a third gap.
22. The device of claim 1 , further comprising a fifth conductive pad attached to the first VSDM, the fifth conductive pad separated from any of the first and second conductive pads by a third gap, the fifth conductive pad electrically connected to either the first or second conductive lead.