NeXLev®
FAQs
Electrical | Mechanical
| SMT Application
Electrical
What
is the current rating of the signals and shields?
1.0 amp per contact signal/1.0 amp per shield contact continuous
duty.
What is meant by the term
'real signal pins'?
The maximum number of pins usable for signal transmission
while providing less than 5% backward and forward crosstalk
and less than 5% reflection at the desired risetime.
What
is the real signal density?
The number of 'real signal pins' per inch (cm)
What
is the contact resistance between the signal and the pad on
the board?
This is essentially the resistance of the solder ball which
is included in the LLCR specification for all contacts.
What
is the voltage rating?
The DWV is 600 Vrms
How
did you measure the signal crosstalk?
Reference the Electrical Characterization Report, available
on the Signal Integrity
page, section 3.0.
Does
the signal integrity change at different stack heights?
Yes, but by studying the Electrical Characterization Report,
available on the Signal Integrity
page, one can see that the change is minimal even at 30mm
height.
What
is the maximum span that two NeXLev connectors can be placed
at, on two mating boards, and not have mating alignment issues?
This is dependent on PCB fabrication tolerances for the specific
PCB being designed. The PCB location tolerances from nominal
would need to meet the following: The connectors can be misaligned
± 0.2 mm in the width direction, or ± 0.1mm
in the length direction, and still maintain electrical continuity.
What
is the "gatherability" of the connector?
The values are ± .22mm
in the width, and ± 1.15mm in the length direction.
Mechanical
What
is the insertion/mating force?
0,45 N/signal (i.e. 300 I/O module = 135N (approximately 30lbs)
What
is the normal force per contact?
0,35 N (35 grams) minimum
What
overall mating forces should I expect?
For a 200 I/O module = 90N (approximately 20 lbs.)
For a 300 I/O module = 135N (approximately 30 lbs.)
How much wipe
do I get?
1.0mm minimum
Are these
modules stackable end to end or side to side?
The connectors are not stackable in the same manner as the
HDM or VHDM connectors due to the need for locating pins and
solder rework station tool clearance.
How are
the connectors polarized?
The plastic insulator of the connector is internally polarized
to prevent 180 degree mis-mating.
Can I key a connector?
No
What product
verification testing is available?
Telcordia compliance per GR-1217-CORE, signal integrity characterization
and solder joint reliability test are available. For more
information, visit the Product Verficiation
section of this web site.
What
are the smallest and largest stack heights?
10mm and 33mm
How are
the contacts protected from damage?
The contacts are oriented to provide lateral float. The contacts
are widely spaced in the connector housing. The housing is
designed to guide the plug wafers into proper mating.
How do we
package the product?
Standard production packaging in JEDEC style trays.
What
is 'cylinder on cylinder' contact interface?
This contact interface is an industry proven and accepted
interface. It provides the best electrical interface without
the prohibitively high mating force.
What is
the durability of cycle life of the connector?
100 mating cycles minimum
Can the connector
be repaired/replaced?
Yes, the entire connector can be replaced using typical BGA
techniques. A controlled hot air repair station can be used.
See TB2082 - SMT Parallel Board Connector Application Guide
in the Technical Bulletin section.
Should
I avoid putting explicit power or ground/return pins near the
signal pins to avoid lowering the nominal 50-ohm characteristic
impedance?
- You can
use signal pins as power and ground return pins, but the
impedance effects will vary according to what pattern you
use. To avoid the effects from any impedance change, run
only low-speed signals adjacent to power/ground pins.
- Running
power through either bussed signal pins, or the ground shield
is the primary method for handling power/ground return in
the connector. By communing all of the signals in a wafer,
up to 10 Amps can be run (per 10 signals) at a 30 degree
C rise. A wafer shield is also capable of handling approximately
9-10 Amps. See Current vs. T rise report in the Product
Verification section of this website.
- The ground
blades are the most efficient way to handle ground or power
return; they have a very low voltage drop, in the range
of < 4 milliohms for all heights. It generally will not
be necessary to use signal pins.
SMT Application
Are there any
special processing requirements?
NeXLev can be assembled using standard SMT/BGA equipment and
processes. However, because it is a BGA connector with a mechanically
compliant structure, there are important process guidelines
that should be followed such as ball-field alignment and best-fit
placement. See Technical Bulletin TB2082 in the Technical
Bulletin section of this site for more detailed information.
Will the connector
twist and warp during the SMT reflow profile?
The plastic material is a liquid crystal polymer and has a
DTUL(device temp. under load) of 280 °C, and should not be
significantly affected by typical reflow profiles. Warp and
twist during reflow has not been an issue.
At what JEDEC
moisture level is the connector designed to?
Does not apply - NeXLev is not a moisture sensitive package
as defined by the following specifications - IPC/JEDEC J-STD-020A,
Moisture/Reflow Sensitivity Classification and J-STD-033 Standard
for Packaging/Shipping.
What is the
solder ball's geometry after reflow?
Barrel shaped with a calculated height of 18-24 mils, and
a maximum diameter of 34 mils - based on actual measurements
done with cross sectioning.
Will the connector
fall off the PCB if it's run upside down in double sided reflow?
Because of the surface tension forces created by a NeXLev
solder joint, the majority of connector sizes can run upside
down in a double sided reflow process. See Technical Bulletin
TB2082 in the Technical Bulletin
section of for more detailed information. The final decision
to run NexLev connectors upside down, without any secondary
method of retention, is the customer's. For more information
on possible methods of retention - contact Amphenol TCS.
The solder balls
on my connectors look uneven. Is this a concern?
No, parts are inspected in relationship to the ball field
as a whole, not in relation to its neighbors. The human eye
does a great job of finding variations to neighbors, but this
is not necessarily indicative of the true positional accuracy
of that ball. See Technical Bulletin TB2082 in the Technical
Bulletin section for more detailed explanation and example
of this condition.
Is it possible
to re-ball a connector to reuse in repair, and if so, how
many times can it be reused?
No, there are no available re-balling processes, and reuse
is not possible.
What is the
recommended orientation and placement of multiple connectors?
The NeXLev connectors should be placed on the board so that
they face in the same direction. This optimizes the float
tolerances designed into the connector. See Technical Bulletin
TB2082 in the Technical Bulletin
section for more detailed information.
How much space
should be allowed between the connectors?
3 mm minimum - 5 mm is preferred. See Technical Bulletin TB2082
in the Technical Bulletin section
for more detailed information.
What is the
Maximum X-Y error at insertion?
This is specified as "post mating float", meaning that once
the connectors are mated, or during mating, the connectors
can be misaligned ± 0.2mm in the width direction, or
± 0.1 mm in the length direction, and still maintain
electrical continuity. This feature was designed in to facilitate
multiple connector applications, but is also available for
gathering during mating. See Technical Bulletin TB2082 in
the Technical Bulletin section
for more detailed information.
What do you
recommend for blind mating applications?
Use 2-board mounted guide pins that would positively align
the cards. The pins could mate with drilled holes in the other
card. Another option would be to align the edges of both cards,
or align a notch in one edge of one card with a pin in the
other, and then seat the connectors. There should be enough
gathering available for this to work. Still another option
would be standoffs with a threaded, male end that could be
used as a guidance feature to pre-align the boards.
What is the
best method for un-mating a NeXLev connector?
Example using a 300-signal module would require about 20-22
lbs. maximum un-mating force. This could be accomplished by
pulling on the daughtercard. The connector can also be pivoted
out, by separating one end of the daughtercard, creating a
lever effect. Another option would be to use jackscrews to
un-mate the connectors, which could double as standoffs to
retain the cards at the proper spacing.
Do you have
any guidelines for running 48 V through NeXLev? Are there
applications out there that do this sort of thing?
One of the things we can do is run the power through an end
wafer, and leave an empty slot in the second position. That
would give us additional clearance, or spacing, to isolate
the 48 volts. UL-1950 governs the amount of spacing that's
required at higher voltages. It may make more sense, seeing
as how we'd need to provide a -48 V ground return, to load
the wafers : +48 V power--space---48 V return--space-full
load the remaining wafers. In just about all of the designs
we've worked with before, the 48 V is run to the daughter-card,
stepped down there, and then run at lower voltages to the
mezzanine card. It is usually driven by what makes sense from
the system architecture point of view.
What is the
X and Y offset of Pin A1, from the plug footprint on one board
to the receptacle footprint on the mating board?
There is no X and Y offset - the PCB footprints align exactly.
Can Amphenol TCS
provide me with recommended reflow profiles for NeXLev?
No, reflow profiles are solder paste manufacturer dependent.
A customer's profile requirements will vary based on the solder
paste being used. See Technical Bulletin TB2082 in the Technical
Bulletin section for more detailed information.
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