Integrated circuit mounting board with bypass capacitors

Details Integrated circuit mounting board with bypass capacitors Integrated circuit mounting board with bypass capacitors

1999-01-22

2001-11-20

Gaffin, Jeffrey (Department: 2841)

Electricity: electrical systems and devices

Housing or mounting assemblies with diverse electrical...

For electronic systems and devices

C361S763000, C361S764000, C361S766000, C361S830000

Reexamination Certificate

active

06320758

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to integrated circuit (IC) technology and more particularly. to an IC mounting board for use to mount an IC module and at least one bypass capacitor thereon.
2. Description of Related Art
An IC mounting board is a circuit board designed in particular to mount an IC module thereon. Customarily each power pin of the IC module is connected to a bypass capacitor for the purpose of filtering out any AC components in the power being supplied to the internal circuit of the IC module. The IC mounting board is typically designed with a complex layout of circuit lines used for connection with the pins of the IC module. Since an IC module typically includes a great number of pins, the layout of the circuit lines on the IC mounting board is highly complex to carry out.
A conventional IC mounting board is depicted in the following with reference to
FIGS. 1 and 2
; wherein
FIG. 1A
is a schematic top view of the conventional IC mounting board (designated by the reference numeral
100
), and
FIG. 1B
is a schematic side view of the same.
As shown, the conventional IC mounting board
100
including an array of IC soldering points
110
for mounting an IC module
115
thereon through soldering means. Moreover, the IC mounting board
100
includes a plurality of paired SMD (Surface Mounted Device) soldering points
120
arranged around the area defined by the IC soldering points
110
, each pair being used to mount a bypass capacitor
125
thereon through soldering means. In this preferred embodiment, for example, the IC module
115
is packaged through the Ball Grid Array (BGA) technology, while the bypass capacitor
125
is an SMD component. There exist, however, some drawbacks to this IC mounting board.
First, the chip (not shown) contained in the BGA-packaged IC module
115
is typically mounted on a small multi-layer printed circuit board (PCB) and electrically connected to the IC soldering points
110
via the printed wires and tin balls on the multi-layer PCB. In order to make the IC module more compact, the number of layers in the multi-layer PCB should be minimal, typically two. The power pins of the IC module
115
are typically arranged in the middle of the bottom side for the purpose of reducing the overall length of the power transmission lines between the IC module
115
and the power supply (not shown). Conventionally, however, the soldering points
120
are arranged outside the area defined by the IC soldering points
110
as illustrated in
FIG. 1A
, and moreover, these soldering points
120
are separated from the IC module
115
by a distance so that they would not impede the mounting and dismounting of the IC module
115
For these reasons, the bypass capacitor
125
are mounted considerably far away from the power pins of the IC module
115
, and therefore, the elongated power transmission path between the bypass capacitor
125
and the power pins (not shown) of the IC module
115
would cause the bypass capacitor
125
to provide the bypass effect less effectively. Therefore, an increased number of bypass capacitors should be provided to enhanced the bypass effect. For instance, in the case of using four different power supplies in the IC module
115
, it requires the use of a doubled number of bypass capacitors, i.e, eight, to provide satisfactory bypass effect to the power supply lines.
Moreover, in the case of the IC module
115
having a large number of pins, the conventional arrangement of the bypass capacitors
125
around the IC module
115
would cause the layout design for the IC mounting board to be very difficult to carry out. Typically, a chipset IC module for computer motherboard may have several hundreds of pins that require the same number of circuit lines on the IC mounting board for interconnection. Therefore, the arrangement of the bypass capacitor
125
around the IC module
115
would greatly complicate the layout design work for the IC mounting board. The circuit lines on the IC mounting board may need to be detoured to avoid the bypass capacitors
125
. The lengthened signal transmission path may then affect the quality of the data signals being transmitted thereover. Solutions to this problem include the use of multi-layer PCB
3
with more layers or a large PCB to implement the IC mounting board. These solutions, however, would undesirably increase the manufacturing cost.
Still moreover, the arrangement of the bypass capacitors
125
around the IC module
115
would impede the mounting and dismounting of the IC module
115
. For instance, in the case of the IC module
115
being a BGA package, the mounting and dismounting of the IC module
115
requires the prior dismounting of the bypass capacitors
125
, thus making the disassemble work very difficult and laborious to carry out.
SUMMARY OF THE INVENTION
It is therefore an objective of the present invention to provide an IC mounting board, which allows the layout of the wiring between the IC module and the circuit lines on the IC mounting board to be more convenient to implement.
It is another objective of the present invention to provide an IC mounting board, which allows the bypass capacitors to be mounted in such a manner as to allow the bypass capacitors to provide the bypass effect more effectively so as to reduced the total number of the bypass capacitors.
In accordance with the foregoing and other objectives of the present invention, a new IC mounting board is provided. The IC mounting board is designed for use to mount an IC module and at least one bypass capacitor thereon. The IC module has a plurality of pins including at least one power pin. The IC mounting board comprises: a plurality of IC soldering points for use to mount the IC module on the IC mounting board; and at least one mounting hole, provided at a predefined location within the area defined by the IC soldering points, for use to mount the bypass capacitor on the IC mounting board, with the bypass capacitor being connected to the power pin of the IC module.
The bypass capacitor is mounted in the capacitor mounting hole in an upright manner with respect to the IC mounting board, having a first end connected to a front-side soldering point connected to the power pin of the IC module, and a second end connected to a back-side soldering point connected to the ground.
Moreover, the capacitor mounting hole is provided with at least one metal foil, preferably a pair of metal foils therein. These metal foils can help prevent the bypass capacitor, when soldered in position, from being dismounted off position when soldering the IC module in position on the IC mounting board. In addition, these metal foils can help prevent the capacitor mounting hole, when the IC mounting board is being dipped in a tin oven., from being sealed off by the solder in the tin oven.


REFERENCES:
patent: 4878155 (1989-10-01), Conley
patent: 5168432 (1992-12-01), Murphy et al.
patent: 5361491 (1994-11-01), Oomachi et al.
patent: 5479319 (1995-12-01), Werther
patent: 5854534 (1998-12-01), Beilin et al.
patent: 6075700 (2000-06-01), Houghton et al.

Affiliated with

Also associated with

Rating

Integrated circuit mounting board with bypass capacitors does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Integrated circuit mounting board with bypass capacitors, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Integrated circuit mounting board with bypass capacitors will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2606762