Paddle card with improved performance
A paddle card construction disclosed for use in connecting electronic devices together. The paddle card takes the form of a circuit board that has a plurality of conductive contact pads arranged thereon in pairs. The contact pads of each pair are spaced apart from each other to provide a pair of points to which cable wire free ends may be terminated, such as by soldering. The spacing of the pads apart from each other in effect reduces to amount of capacitance in the cable wire termination area on the circuit board, thereby reducing the impedance and insertion loss in that area at high frequencies. The contact pads of each pair may be further interconnected together by a thin, conductive trace that extends lengthwise between the contact pads.
1. A cable assembly, the cable assembly comprising:
a cable, the cable including a plurality of signal-transmitting wires, pairs of the signal-transmitting wires being arranged in the cable, each signal-transmitting wire including a conductor surrounded by an insulative covering, each conductor extending forwardly past a leading edge of the insulative covering to define a free end of each signal-transmitting wire; and
a circuit board, the circuit board having opposite leading and trailing edges, the circuit board including a first portion to which the free ends are terminated and a second portion extending forwardly from and spaced apart from the first portion, the first portion including a plurality of contact pads disposed on a surface thereof, the contact pads being arranged in pairs of contact pads associated with each free end, the contact pads of each contact pad pair being aligned with each other so that a leading edge of the foremost contact pad and a trailing edge of the rearmost contact pad define a predetermined length, L, there between, the contact pads being separated from each other by an intervening spacing, the cumulative length of the contact pads being between about 0.5 L to 0.8 L;
wherein each free end of the signal-transmitting wires contacts both the contact pads of one of the pairs of contact pads.
2. The cable assembly of claim 1 , wherein each contact pad pair includes a thin, conductive trace interconnecting the pads of each contact pad pair together.
3. The cable assembly of claim 1 , wherein at least one pad of the pairs of contact pads encompasses a via extending into the circuit board.
4. The cable assembly of claim 3 , wherein each pad of each pair of contact pads encompasses a via extending into the circuit board.
5. The cable assembly of claim 1 , wherein the pairs of contact pads are spaced widthwise apart from each other by a first predetermined spacing, and the circuit board further includes conductive transmission traces extending from the forwardmost contact pads in a direction toward the first portion, the transmission traces being separated by a second spacing which is less than the first spacing.
6. The cable assembly of claim 5 , wherein the transmission traces converge toward each other until separated by the second spacing.
7. The cable assembly of claim 1 , wherein the contact pads have a length of about 0.8 mm, and the intervening spacing between the contact pads has a length of about 1.0 mm.
8. The cable assembly of claim 1 , wherein the intervening spacing is between about 0.2 L to about 0.4 L.
9. The cable assembly of claim 1 , wherein each interconnecting trace is generally centered between the pair of contact pads it connects together.
10. The cable assembly of claim 1 , wherein each interconnecting trace has a width of about 25% to about 40% of a width of the contact pads.