Electrical connectors – With insulation other than conductor sheath – Plural-contact coupling part
Reexamination Certificate
1999-04-16
2001-11-13
Sircus, Brian (Department: 2839)
Electrical connectors
With insulation other than conductor sheath
Plural-contact coupling part
C439S159000
Reexamination Certificate
active
06315614
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to memory modules for expanding memory capacity in computer systems and to memory module connectors.
2. Description of the Related Art
Both single in-line memory modules (SIMMs) and dual in-line memory modules (DIMMs) and corresponding memory module connector sockets for expanding memory with computer systems are well known. Generally speaking, in-line memory modules include a printed circuit board on which a plurality of memory chips such as DRAMs are surface mounted. A connective portion along one edge of the printed circuit board is adapted for insertion into a mating (i.e. accommodating) space of a connector. A plurality of contact pads (also called pins) on the connective portion mates with a plurality of corresponding contacts inside the accommodating space of the connector to provide for the transfer of electrical signals between the memory module and the rest of the computer system.
On a SIMM, the connective portion usually includes a plurality of contact pads on either the front side of the edge of the printed circuit board or on both the front and back sides of the printed circuit board. In configurations that include contact pads on both the front and back sides of a SIMM, opposing contact pads on the two sides are typically shorted together and therefore carrying the same electrical signal. In a DIMM, the contacts are positioned in the connective portion on both the front and back sides of the printed circuit board. At least some of the opposing contact pads on the two sides of the printed circuit board of a DIMM are configured to carry differing electrical signals, thereby increasing the signal density without necessitating smaller contact pads or a larger printed circuit board.
FIGS. 1A and 1B
illustrate two embodiments of prior art DIMM memory modules
100
and
150
, respectively. Memory modules
100
and
150
, as shown, include
84
contact pads, such as contact pads
115
A and
165
A, on the front side, for
168
total contact pads. It is noted that the number of contact pads may vary such that memory modules with up to
200
contact pads are available on the market.
Memory modules
100
and
150
are configured to couple to appropriate memory module connectors, which are specifically designed to mate and secure the memory module. In general, a connector comprises a housing including an accommodating space, which is adapted to receive a portion of the printed circuit board of the memory module.
Turning to
FIG. 1A
in detail, memory module
100
includes a printed circuit board
110
. A region
103
, shown with dashed lines, for the placement of semiconductor integrated circuits, such as DRAM memory chips or other appropriate memory, occupies the majority of the space on a face of the printed circuit board
110
. The contact pads
115
are disposed along one edge (i.e. the connective portion) of the printed circuit board
110
from a short distance from the left end to approximately the same distance from the right end. The center of the length of the printed circuit board
110
is marked with a centerline
101
. A single notch
120
is positioned along the one edge at substantially the center of the edge of the printed circuit board
110
. In other known embodiments, notch
120
may alternatively be positioned approximately one-half of the width of the notch to either side of the center location, as noted with dashed lines. Additional details regarding the notches
120
may be found with respect to
FIG. 1C
below. The printed circuit board
110
also includes indentions
105
A and
105
B positioned on the left end and right end, respectively. The indentations
105
A and
105
B are shaped to receive module extractors, which may be included as a part of the connector, to hold the memory module
100
in place when the module extractors are in a closed position.
Turning to
FIG. 1B
in detail, memory module
150
includes a printed circuit board
160
. The contact pads
115
are disposed along one edge of the printed circuit board
160
. The center of the length of the printed circuit board
160
is marked with a centerline
151
. A center notch
120
A is positioned along the one edge at substantially the center of the edge of the printed circuit board
160
. Memory module
150
also includes a left notch
120
B positioned to the left of center. Similar to the center notch
120
A, the location of the left notch
120
B is also known in other embodiments to be repositioned approximately one-half of the width of the notch
120
B to either side of the illustrated location. The printed circuit board
160
also includes indentions
105
C and
105
D positioned on the left end and right end, respectively.
FIG. 1C
is a close-up view of a notch
120
. As shown, notch
120
is located on the edge of the printed circuit board
110
or
160
in a space along the row of contact pads
115
. The height of the notch
120
is just slightly higher than the corresponding size of the contact pads
115
.
It is noted that the notches
120
are configured to mate with keys in the accommodating space in the housing of the corresponding connector. A center key, which is configured to mate with a center notch
120
or
120
A, of the connector may be referred to as the “voltage key”, while the left key, which is configured to mate with left notch
120
B, may be referred to as the “functionality key”. The names refer to the different voltages and/or functionalities that the three locations for each key (and therefore notch) correspond, depending on the manufacturer or standard.
One problem associated with the memory modules
100
and
150
is the difficulty in correctly installing the memory module
100
or
150
in the corresponding connector. Even with installation guides as a part of the connector, the memory module
100
or
150
may be installed backwards or unevenly. While the use of a polarized two-notch memory module, such as memory module
150
, may decrease the likelihood of installing the memory module backwards, the notches
120
A and
120
B may not aid in installing the memory module evenly. It may be possible to install the memory module
150
with a slight tilt leading to one or more misconnections or even shorts. A related problem is the stability of the memory module
100
or
150
once inserted in the corresponding connector. Additional stabilizing features may inhibit simple and accurate insertion, which may further lead to uneven insertion and improper connections. Thus, it can be seen that an improved memory module, connector, and system thereof with improved ease of insertion and stability are desired.
SUMMARY OF THE INVENTION
The problems outlined above are in large part solved by an improved memory module with offset notches for improved insertion and stability and an improved memory module connector configured to receive the memory module. In one embodiment, the connector includes a first end, a second end, and a center midway between the first end and the second end. The connector housing further includes an accommodating space for receiving a connective portion of a printed circuit board of a memory module. A first key and a second key are disposed within the accommodating space of the housing. The first key is positioned between the first end of the housing and the center. The second key is positioned between the second end of the housing and the center. A distance between the first key and the second key is greater than 40% of the length of the connector housing. In one embodiment, one or more of the first key and the second key extend from the accommodating space beyond a top plane defined by a top side of accommodating space of the housing. The distance between the keys may advantageously allow for greater stability for a memory module coupled to the connector without compromising ease of insertion.
In another embodiment, a memory module is contemplated that includes a printed circuit board including a connective portion configured to be inserted into a memory module connector. T
Hassanzadeh Ali
Odisho Victor
Conley Rose & Tayon PC
Kivlin B. Noäl
Sircus Brian
Sun Microsystems Inc.
Zarroli Michael C.
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