Flexible printed circuit finger layout for low crosstalk
A flexible printed circuit (FPC) for a hard disk drive includes a plurality of electrical traces, whereby aggressor traces are isolated from victim traces to avoid crosstalk that could degrade signals. Aggressor traces may be positioned together at one of the edges of each of the top wiring layer and the bottom wiring layer, physically isolated from victim traces. Aggressor traces may be grouped together at either the top wiring layer or the bottom wiring layer, with the victim traces positioned on the layer opposing the aggressor traces. With aggressor and victim traces routed on the same wiring layer, aggressor traces may be routed away from the victim traces with multi-layer routing, by way of vias.
1. A flexible printed circuit (FPC) for a hard disk drive having a top wiring layer having opposing lateral edges extending longitudinally, a bottom wiring layer having the opposing lateral edges extending longitudinally, and a proximal end in the direction of a preamp, the FPC comprising:
a plurality of electrical traces, including aggressor traces configured to carry signals that can interfere with signals carried by victim traces, wherein the aggressor traces comprise a top pair of aggressor traces positioned adjacently at one common lateral edge of the proximal end of the top wiring layer and a bottom pair of aggressor traces positioned adjacently at the common lateral edge of the proximal end of the bottom wiring layer;
one of a ground trace or a thermal flying height control (TFC) trace positioned at the proximal end of the bottom wiring layer opposing the top pair of aggressor traces; and
the other of the ground trace or the TFC trace positioned at the proximal end of the top wiring layer opposing the bottom pair of aggressor traces.
2. The FPC of claim 1 , wherein the aggressor traces carry write signals.
3. A hard disk drive comprising the FPC of claim 1 .
4. A flexible printed circuit (FPC) for a hard disk drive having a top wiring layer having opposing lateral edges extending longitudinally, a bottom wiring layer having opposing lateral edges extending longitudinally, and a proximal end in the direction of a preamp, the FPC comprising:
a plurality of electrical traces comprising:
aggressor traces, configured to carry signals that can interfere with signals carried by victim traces, grouped together adjacently at a common lateral edge of the proximal end of either the top wiring layer or the bottom wiring layer; and
all of the victim traces positioned on the top wiring layer or the bottom wiring layer opposing the aggressor traces.
5. The FPC of claim 4 , wherein the aggressor traces carry write signals and the victim traces carry read signals.
6. The FPC of claim 4 , wherein the aggressor traces are grouped together at the proximal end of the top wiring layer, the FPC further comprising:
a ground trace positioned at the common lateral edge of the proximal end of the bottom wiring layer opposing the aggressor traces.
7. The FPC of claim 4 , wherein the aggressor traces are grouped together at the proximal end of the bottom wiring layer, the FPC further comprising:
a ground trace positioned at the common lateral edge of the proximal end of the top wiring layer opposing the aggressor traces.
8. A hard disk drive comprising the FPC of claim 4 .
9. A flexible printed circuit (FPC) for a hard disk drive having a top wiring layer having opposing lateral edges extending longitudinally, a bottom wiring layer having the opposing lateral edges extending longitudinally, and a proximal end in the direction of a preamp, the FPC comprising:
a plurality of electrical traces, including aggressor traces configured to carry signals that can interfere with signals carried by victim traces, wherein the aggressor traces comprise a top pair of aggressor traces positioned adjacently at the proximal end of the top wiring layer and an opposing bottom pair of aggressor traces positioned adjacently at the proximal end of the bottom wiring layer; and
a thermal flying height control (TFC) trace positioned between the aggressor traces and the victim traces at the proximal end of each of the top wiring layer and the bottom wiring layer.
10. The FPC of claim 9 , wherein the aggressor traces carry write signals.
11. A hard disk drive comprising the FPC of claim 9 .