Information
-
Patent Grant
-
6749444
-
Patent Number
6,749,444
-
Date Filed
Wednesday, January 16, 200222 years ago
-
Date Issued
Tuesday, June 15, 200420 years ago
-
Inventors
-
Original Assignees
-
Examiners
-
CPC
-
US Classifications
Field of Search
US
- 439 79
- 439 620
- 439 607
- 439 108
- 439 101
- 439 941
- 439 676
- 174 255
-
International Classifications
-
Abstract
An interchangeable impedance tuner for use in an electrical connector has been provided. The tuner is formed of a dielectric material different than air. The interchangeable impedance tuner may include a plurality of dielectric isolation ribs, wherein a dielectric rib is positioned between two adjacent signal and/or ground contacts. The tuner may also include at least one impedance adjusting metal insert and at least one insert receptacle for slidably receiving the impedance adjusting metal insert. Each impedance adjusting metal insert is oriented parallel to a portion of the contacts. Further, each impedance adjusting metal insert overlaps a portion of one of the differential pairs. A shell covering the housing and the tuner. The shell opens to allow removal of the tuner is also provided. Upon removal of one tuner, a different tuner, having different impedance controlling characteristics may be positioned within the cavity of the electrical connector.
Description
BACKGROUND OF THE INVENTION
Certain embodiments of the present invention generally relate to a connector for electronic equipment, and more particularly to a connector including an interchangeable tuner for controlling the impedance within the connector.
Connectors are known for interconnecting various electrical media, components, and structures such as printed circuit boards (PCB), coaxial cables, discrete circuit components, flex circuits and the like. The connectors may interconnect signal and/or power lines between two similar or different media, components and structures, such as between a flex circuit and a PCB, between two PCBs and the like. An example of an interconnection between two PCBs is a board-to-board connector. Connectors are offered in a variety of shapes and sizes, depending upon several competing criteria. Within connectors, the shape, size and spacing between contacts also greatly varies. As the shape, size and spacing of the contact changes, so does the impedance exhibited by the contacts.
Today, connectors are being proposed with more and more signal lines within smaller and smaller connector envelopes. Such size reductions and capacity increases have resulted in very close spacing between adjacent contacts within a connector. As contacts became more closely spaced, when carrying high speed signals, adjacent contacts begin to electrically couple with one another. Electrical coupling occurs when one contact becomes influenced by the electromagnetic field produced by an adjacent contact. Electrical coupling causes, among other things, the contacts to exhibit different impedance characteristics than they might otherwise exhibit absent any coupling. Until recently, impedance exhibited by a connector did not degrade performance by an appreciable amount, in part because signal/data transmission rates were relatively low (e.g., less than 500 MHz or 1 Gbits per second). However, newer electronic and electrical systems have been proposed that are able to transmit data signals at speeds approaching and exceeding 1 GHz or 2 Gbits per second. Because the speed of data transmission systems continues to increase, while the physical size of components continues to decrease, even small increases in impedance may pose significant problems, such as signal loss, within a connector and the system.
Many board-to-board systems have been proposed that include connectors that apply differential pairs of signals. Differential signal pairs include complimentary signals such that if one signal in a differential pair switches from 0 V to 1 V, the other signal in the differential pair switches from 1 V to 0 V. Differential pair connectors have been proposed that control impedance by using a predetermined contact-to-contact spacing (e.g., a distance between signal contacts of a differential pair). Impedance is affected by contact-to-contact spacing because impedance increases as capacitance decreases. Capacitance increases as the distance decreases between a signal contact, or tail, and ground or other signal contacts, or contacts. Hence, impedance decreases with decreased contact-to-contact spacing. Conversely, impedance increases with increased contact-to-contact spacing. Therefore, signal contacts of conventional systems are positioned a predetermined distance from adjacent signal contacts in order to yield a desired impedance.
As the distance increases between two contacts in a differential pair or otherwise, the contacts are considered to be “loosely coupled” to one another. Similarly, as the distance is decreased between contacts in a differential pair or otherwise, the contacts are considered to be more “tightly coupled” to one another. Loosening the coupling of signal contacts of a differential pair increases the impedance exhibited at the contacts, while tightening the coupling between signal contacts in a differential pair decreases the impedance.
Increasing the distance between signal contacts of a differential pair also increases the interference, noise and jitter experienced by the signals carried through circuit boards, the connector and contacts. For example, as a signal contact of a differential pair is displaced further from its complimentary signal contact, the signal contacts of one differential pair may become coupled to signal contacts of a different differential pair. As signal contacts of separate differential pairs become coupled to one another, the signal contacts begin to exhibit cross-talk with each other. That is, loosening the coupling between complimentary signal contacts may tighten the coupling between non-complimentary signal contacts. Tightening the coupling between non-complimentary signal contacts increases cross-talk between the contacts. Consequently, interference, noise, and jitter within the multi-layer circuit board, connector and system increases. Therefore, increasing the distance between signal contacts to increase the impedance within a particular differential pair causes a higher degree of interference, noise and jitter. Conversely, decreasing the distance between signal contacts of a differential pair to decrease the amount of interference, noise and jitter may produce a non-uniform or otherwise non-suitable impedance.
A need remains for an improved electrical connector capable of controlling impedance within desired levels.
BRIEF SUMMARY OF THE INVENTION
In accordance with an embodiment of the present invention, a connector assembly has been developed that includes a connector housing having a contact retaining chamber at one end of the connector housing, at least two signal contacts arranged as a differential pair and held in the contact retaining chamber of the connector housing. The signal contacts are separated by a gap. The assembly also includes an impedance tuner block formed of a dielectric material insertable into the contact retaining chamber. The impedance tuner block has at least two channels notched therein. The impedance tuner block includes isolation layers separating the channels. Each channel receives a corresponding one of the signal contacts and each isolation layer is inserted between adjacent signal contacts when the impedance tuner block is inserted into the contact retaining chamber.
The impedance tuner block may also include a plurality of isolation ribs as the isolation layers. One isolation rib is positioned between two adjacent contacts. Optionally, the connector assembly may further include ground contacts separating the differential pairs from one another. The differential pairs may be separates from the ground contacts by the isolation ribs.
The connector assembly further includes at least one impedance adjusting insert securable to the impedance tuner block in a position that is oriented parallel to at least central elongate arms of the signal contacts. The impedance adjusting inserts may be formed of a non-ferrous metal.
Further, embodiments of the present invention include a shell covering the housing and the impedance tuner. The shell opens to allow removal of the impedance tuner. Upon removal of one impedance tuner, a different impedance tuner, having different impedance controlling characteristics may be positioned within the cavity of the electrical connector.
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
FIG. 1
is an isometric view of a receptacle connector formed in accordance with an embodiment of the present invention.
FIG. 2
is an isometric view of an impedance tuner formed in accordance with an embodiment of the present invention.
FIG. 3
is an isometric view of an impedance tuner formed in accordance with an embodiment of the present invention.
FIG. 4
is an isometric view of an impedance tuner with metallic inserts formed in accordance with an embodiment of the present invention.
FIG. 5
is an isometric view of an impedance controlled connector assembly
500
formed in accordance with an embodiment of the present invention.
FIG. 6
is an isometric view of an impedance controlled connector assembly
500
formed in accordance with an embodiment of the present invention.
The foregoing summary, as well as the following detailed description of certain embodiments of the present invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings, certain embodiments. It should be understood, however, that the present invention is not limited to the arrangements and instrumentality shown in the attached drawings.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1
is an isometric view of a receptacle connector
100
formed in accordance with an embodiment of the present invention. The receptacle connector
100
includes a housing
110
having a main body
110
, and sidewalls
111
, a back wall
117
and a base
115
that define a cavity
120
at an open face of the housing
110
. Contact passages
128
are formed in the open end of the base
115
. Ground contacts
122
extend from the back wall
117
. Each ground contact
122
has a ground contact tail
133
at a terminal end. Similarly signal contacts
126
extend from the back wall
117
, and each signal contact
126
has a signal contact tail
137
at a terminal end. The signal and ground contacts
126
and
122
carry differential pair data signals at high speeds, such as 2 Gbits per second, 5 Gbits per second, 10 Gbits per second and the like.
Signal and ground contacts
126
and
122
are interspersed with two (2) signal contacts
126
being adjacent one another, thereby forming a differential pair
124
. Adjacent differential pairs
124
are separated from one another by a ground contact
122
. As shown in
FIG. 1
, each signal and ground contact
126
and
122
includes an elongated central arm
136
and
132
, respectively, with an arc shaped contact tail
137
and
133
, respectively, on a lower end thereof. Each signal contact
126
and ground contact
122
also includes signal and ground lead contact sections
146
and
142
, respectively, at the upper end opposite that of the arc shaped contact tails
137
and
133
. Each signal and ground contact tail
137
and
133
curves below and outward from a contact passage
128
. The contact passages
128
are separated by a series of sections
149
having beveled outer tips. The signal contacts
126
in each differential pair
124
are spaced apart by a width W
D
that includes the width of each signal contact
126
plus the space between the signal contacts
126
.
The connector
100
also includes a shell (not shown) that covers the housing
110
and cavity
120
. The end
103
of the receptacle connector
100
opposite the cavity
120
is received by a plug connector (not shown) having signal and ground contacts (not shown) that connect to the signal contacts
126
and ground contacts
122
, respectively, through intermediate signal and ground portions (not shown), respectively. The plug connector, in turn, connects to an electrical cable (not shown) that allows signals to pass from the plug connector to the cable and ultimately to an electrical component (not shown), and vice versa.
FIGS. 2 and 3
are isometric views of an impedance tuner
200
formed in accordance with an embodiment of the present invention. The impedance tuner
200
includes a rectangular molded housing
201
having top, bottom, side, front and back walls
208
,
220
,
214
,
216
and
222
and an insert dividing wall
224
. The impedance tuner
200
also includes plank shaped insert receptacles
202
formed and angled within the front wall
216
. The insert receptacles
202
include retaining bases
218
at lower ends of the receptacles
202
and insertion slots
318
having notches
206
formed in the top wall
208
and extending downward therefrom. The insert receptacles
202
receive and retain impedance adjusting inserts (discussed below with respect to FIG.
4
). Thus, the insert receptacles
202
conform to the shape of the impedance adjusting inserts (reference numeral
402
in FIG.
4
). As shown in
FIGS. 2 and 3
, the notches
206
extend less than half the distance from the top wall
208
to the retaining bases
218
. The insert receptacles
202
are separated by the insert dividing wall
224
having a reduced portion
320
between the two notches
206
.
As shown in
FIG. 3
, The impedance tuner
200
also includes dielectric isolation walls, or ribs
302
formed within the back wall
222
. Upon insertion of the impedance tuner
200
into the connector
100
, the ribs
302
separate signal and ground contacts
126
and
122
from one another. The ribs
302
define contact channels
301
that extend into the housing
201
from the back wall
222
. Each contact channel
301
is formed to receive a signal or ground contact
126
or
122
. The impedance tuner
200
is made of a dielectric material, such as a liquid crystal polymer material, or zenite, that has a dielectric constant greater than air. For example, zenite has a dielectric constant of 3.40 while air has a dielectric constant of 1.00.
FIG. 4
is an isometric view of an impedance tuner
200
with impedance adjusting inserts
402
formed in accordance with an embodiment of the present invention. The impedance adjusting inserts
402
may be a non-ferrous metal, such as brass and the like. The impedance adjusting inserts
402
have tabs
404
located on their sides, extending laterally therefrom. The impedance adjusting inserts
402
, each having a width W
M
, are positioned within the insert receptacles
202
such that the tabs
404
are received and frictionally retained by the notches
204
. The retaining bases
218
support the impedance adjusting inserts
402
. When the impedance tuner
200
is positioned with the connector
100
, the impedance adjusting inserts
402
are positioned over differential pairs
124
, as further discussed below.
FIG. 5
is an isometric view of an impedance controlled connector assembly
500
formed in accordance with an embodiment of the present invention. The assembly
500
includes the receptacle connector
100
and the impedance tuner
200
. The impedance tuner
200
is positioned within the cavity
120
such that each signal contact
126
and ground contact
122
is positioned within a contact channel
301
(shown in FIG.
3
). Each signal contact
126
of a differential pair
124
is separated from its counterpart signal contact
126
by a dielectric isolation wall
302
(shown in FIG.
3
). Each signal elongated central arm
136
is separated from a ground elongated central arm
132
by a dielectric isolation wall, or rib
302
(view hidden by insertion of impedance tuner
200
into receptacle connector
100
). Each signal contact tail
137
and ground contact tail
133
protrudes from the base
115
of the receptacle
100
through a contact passage
128
and is exposed in order to contact traces (not shown) on a circuit board (not shown).
The impedance tuner
200
is held into position by the metallic shell (not shown) that encompasses the connector
100
and the impedance tuner
200
. Preferably, the shell is positioned and clamped around the housing
110
. The shell may open and close in order to allow one tuner
200
to be removed, and another impedance tuner
200
to be inserted into the cavity
120
. Thus, the assembly
500
may accommodate a variety of impedance tuners
200
, depending on the desired amount of impedance control. For example, an impedance tuner
200
having a first dielectric constant may be used in some applications. During a different application, the impedance tuner
200
may be removed and replaced with a second impedance tuner
200
having a different dielectric constant, or different impedance adjusting inserts
402
formed of a different metal. In other words, the impedance tuner
200
is interchangeable.
The insert receptacles
202
are formed within the impedance tuner
200
such that each impedance adjusting insert
402
may be positioned in a parallel plane over a corresponding differential pair
124
. The width of each impedance adjusting insert
402
is equal, or approximately equal, to the width of a differential pair
124
(W
M
=W
D
). In any event, each impedance adjusting insert
402
completely overlaps the width of a differential pair
124
. That is, each impedance adjusting insert
402
completely overlaps a portion of a differential pair
124
(e.g., elongated central arms
136
of two signal contacts
126
of a differential pair), but does not touch the signal contacts
126
of the differential pair
124
. Rather, the impedance adjusting inserts
402
are separated from the signal contacts
126
by the molded housing
201
and/or air. That is, the impedance adjusting inserts
402
are separated from the signal contacts
126
by dielectric material.
The impedance adjusting inserts
402
are very closely spaced to the signal contacts
126
and ground contacts
122
, but the impedance adjusting inserts
402
do not touch the contacts
126
and
122
. The impedance adjusting inserts
402
are oriented in a plane that is parallel to the elongated central arms
136
and
132
of the signal contacts
126
and ground contacts
122
in order that the impedance adjusting inserts
402
will conform to a portion of the contacts
126
and
122
. The impedance adjusting inserts
402
may be flat metal sheets
520
that run parallel with and overlap the elongated central arms
136
and
132
of the signal and ground contacts
136
and
132
, respectively. Alternatively, each insert
402
may be a curved metal sheet
540
that conforms to a greater portion of the contacts
126
and
122
than the flat metal sheet
520
. For example, the curved metal sheet
540
may conform to the elongate central arms
136
and
132
and the signal and ground lead contact sections
146
and
142
.
The impedance adjusting inserts
402
are spaced apart from one another so that there is little or no coupling between them. For example, the width of the insert dividing wall
224
may be the width of a ground tail
133
, so long as each impedance adjusting insert
204
overlaps signal contacts
136
of a differential air
124
.
Impedance within the assembly
500
is tuned through the dielectric material of the impedance tuner
200
and the impedance adjusting inserts
402
. Impedance is represented by the following equation:
where Z is impedance, L is inductance and C is capacitance. Therefore, increasing the capacitance decreases the impedance. Decreasing capacitance increases the impedance. Capacitance, is further defined by the following equations:
where Q is the charge on a plate, V is voltage, A is the area of the plates, e
o
is the permittivity of free space and e
r
is the dielectric constant of the material between the plates.
The capacitance of a system including two plates, such as two signal contacts
126
of a differential pair
124
, or a signal tail
126
and a metal plate
402
, may be increased by the following:
1) Increasing the dielectric constant (e
r
) of the material between the plates;
2) Increasing the areas (A) of the plate; or
3) Decreasing the separation between the plates (d).
In order to increase the capacitance, the dielectric material between the plates may be changed. For example, instead of the signal contacts
126
of a differential pair
124
being separated by air, the dielectric isolation walls, or ribs
302
may be placed between the signal contacts
126
, such as in the embodiments discussed above. Alternatively, however, ribs
302
may not be placed between the signal contacts
126
of a differential pair
124
. Rather, the ribs
302
may be placed only between the differential pairs
124
and the ground contacts
122
. Also, alternatively, ribs
302
may not be used. Instead, the impedance tuner
200
may have a molded housing
201
without any ribs
302
. Also, alternatively, the metal inserts
402
may not be used. Instead, the dielectric housing
201
may provide the desired amount of impedance control within the assembly
500
. However, to increase capacitance even further, a neutral piece(s), such as an impedance adjusting insert
402
, may be added to the dielectric material, such as the molded housing
201
. Also, alternatively, instead of dielectric ribs
302
, the impedance tuner
200
may include metal isolation walls, or ribs protruding from the housing
201
and positioned between all or some of the contacts
126
and
122
.
Thus, different impedance tuners
200
may be used within the receptacle connector
100
. Variables that affect the impedance within the system include the following: using impedance tuners
200
of different dielectric materials, varying the depths of contact channels
301
, utilizing impedance adjusting inserts
402
, varying the impedance adjusting inserts
402
among different metals having different dielectric constants, varying the distance between the impedance adjusting inserts
402
and the differential pairs
124
, and/or varying the length of the impedance adjusting inserts
402
that conforms to the signal contacts
126
and ground contacts
122
. Various impedance tuners
200
having different combinations of these variables may be used with the assembly
500
, depending on the desired amount of impedance control within the assembly
500
. Thus, impedance tuning and control through interchangeable impedance tuners
200
is provided.
FIG. 6
is an isometric view of an impedance controlled connector assembly
600
formed in accordance with an embodiment of the present invention. The assembly
600
includes dielectric insert
602
having contact channels
604
. The assembly
600
differs from the assembly
500
in that the dielectric insert
602
is inserted from underneath the contacts
122
and
126
through an opening
601
in the connector base, as opposed to being positioned over the contacts
122
and
126
. The contacts
122
and
126
rest on the contact channels
604
, which conform to the contours of the contacts
122
and
126
. As shown with respect to
FIG. 6
, the dielectric insert
602
does not include metallic inserts.
While the invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.
Claims
- 1. A connector assembly, including:a connector housing; at least two signal contacts arranged as a differential pair and at least one ground contact held in said connector housing, said at least two signal contacts being separated by a gap; an impedance tuner block insertable into said connector housing, said impedance tuner block including a first wall having at least two channels notched therein, said impedance tuner block including isolation layers formed of a dielectric material and separating said channels, each channel receiving a corresponding one of said signal contacts and each isolation layer being inserted between adjacent signal contacts when said impedance tuner block is inserted into said connector housing, said impedance tuner block further including a second wall opposite said first wall, said second wall having at least one insert receptacle; and an impedance adjusting insert in said insert receptacle.
- 2. The connector assembly of claim 1 wherein said impedance tuner block includes a plurality of isolation ribs as said isolation layers, wherein one of said plurality of isolation ribs is positioned between two adjacent signal contacts.
- 3. The connector assembly of claim 1 further including a plurality of differential pairs of signal contacts, and a ground contact separating each of said differential pairs, wherein said impedance tuner block includes a plurality of isolation ribs as said isolation layers, said differential pairs being separated from said ground contacts by said isolation ribs.
- 4. The connector assembly of claim 1 wherein said signal contacts in said differential pair are arranged in a first plane and wherein said impedance tuner block retains said at least one impedance adjusting insert oriented parallel to said first plane.
- 5. The connector assembly of claim 1 further including an impedance adjusting insert securable to said impedance tuner block adjacent to said at least two channels to overlap corresponding signal contacts received in said at least two channels.
- 6. The connector assembly of claim 1 wherein said impedance adjusting insert is held adjacent said differential pair.
- 7. The connector assembly of claim 1, further including multiple sets of differential pairs of signal contacts, said differential pairs aligned in a common plane.
- 8. An apparatus for controlling impedance within an electrical connector assembly including a housing and a plurality of signal contacts and a ground contact substantially coplanar with said signal contacts, said signal contacts being arranged in a differential pair, said apparatus comprising:an impedance tuner formed of a dielectric material different than air and adapted to be interchangeably secured in said housing, said impedance tuner including dielectric isolation ribs along a side of said impedance tuner mating with the signal contacts, said impedance tuner being positioned proximate the signal and ground contacts, wherein signal contacts of the differential pair are separated from the ground contact by one of said isolation ribs.
- 9. The apparatus of claim 8 wherein one of said plurality of isolation ribs is adapted to be positioned between every signal contact.
- 10. The apparatus of claim 8 wherein said impedance tuner further includes:at least one impedance adjusting insert removably secured to said impedance tuner, said at least one impedance adjusting insert being oriented parallel to a plane in which said signal contacts are arranged.
- 11. The connector assembly of claim 8 further including an impedance adjusting insert securable to said impedance tuner block adjacent said signal contacts of said differential pair received in said isolation ribs.
- 12. The apparatus of claim 8 further including a plurality of impedance adjusting inserts, said inserts aligned in a common plane.
- 13. A system for controlling impedance within an electrical connector assembly, comprising:an electrical connector including: a housing; and a plurality of signal contacts and ground contacts aligned in a common plane, said signal and ground contacts held in, and exposed from, said housing, said signal contacts being arranged in differential pairs; an interchangeable impedance tuner formed of a dielectric material different than air, said interchangeable impedance tuner, comprising: an impedance adjusting insert; and an insert receptacle for receiving said at least one insert, said impedance tuner being positioned proximate said plurality of signal contacts and ground contacts, wherein said impedance adjusting metal insert is oriented parallel to said signal contacts, and wherein said impedance adjusting insert overlaps at least two signal contacts.
- 14. The system of claim 13 wherein said interchangeable impedance tuner includes a plurality of dielectric isolation ribs, wherein one of said plurality of dielectric isolation ribs is positioned between two adjacent signal and ground contacts.
- 15. The system of claim 13 wherein said interchangeable impedance tuner includes a plurality of dielectric isolation ribs, wherein one differential pair of signal contacts is separated from a ground contact by at least one of said dielectric ribs.
- 16. The system of claim 13 wherein said at least one impedance adjusting insert is a non-ferrous metal.
- 17. A system for controlling impedance within an electrical connector assembly, comprising:an electrical connector including: a housing; and a plurality of signal contacts and ground contacts held in, and exposed from, said housing, said signal contacts being arranged in differential pairs; an interchangeable impedance tuner formed of a dielectric material different than air, said interchangeable impedance tuner including: a plurality of dielectric isolation ribs on one side surface thereof; an impedance adjusting insert; and an insert receptacle for receiving said at least one insert, said impedance tuner being positioned within said housing proximate said plurality of said signal contacts and ground contacts, wherein one of said plurality of dielectric isolation ribs is positioned between two adjacent signal and ground contacts, wherein said impedance adjusting insert is oriented parallel to said signal contacts, and wherein said impedance adjusting insert overlaps at least two signal contacts.
- 18. The system of claim 17 wherein said one of said plurality of dielectric ribs is positioned between two adjacent signal and ground contacts.
- 19. The system of claim 17 wherein said at least one insert is a non-ferrous metal.
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