Components and Library Management
The way we work with you
What is a custom Backplane?
A custom defined backplane is, as
the name suggests, a backplane dedicated to a specific
application with its own set of electrical requirements
and customized form factor and sometimes even customized
connectors. Projects for military, avionics, medical,
scientific research, to name the most usual, are known
to be based on proprietary specifications. Such a backplane
will exhibit little of the industrial standards features,
such as form factor, bus, signals definition and connectors.
This norm, however, started to change years back. This
is due to two major factors that determined these traditional
users of custom backplanes to reconsider the options.
One is the exacerbated cost of the custom defined components
and the associated NREs and minimum quantities coupled
with the prominent tendency of the market to make use
of the off-the-shelf electronics, such as boards, power
supplies, transition modules which are mostly based
on and compliant to an industrial standard or another.
The other is the increased overall performance of the
off-the-shelf components that matches the tough requirements
of the mentioned industries where adds the big advantage
of these components being extensively tested by the
Nowadays the custom backplanes are
largely based on industrial standards, like PICMG®
or VITA and usually compliancy to these standards is
required. A large portion of the boards used with
these backplanes are compliant to a standard or another
and thus the same requirement for the backplane.
5-segment, quad bridge, 66MHz, 64-bit, 18-slot CompactPCI backplane
This is a backplane that features
one 17 slots-wide, 66MHz, 64-bit CompactPCI bus and
a reserved 18th slot, all controlled by one system slot
CPU board. The form factor was 6U and access to all
slots in the rear was required in order to populate
all 18 Rear Transition Modules. A number of proprietary
signals were required in the P4 and P5 zone.
Due to the fact that only 5 slots,
or loads, are permitted on a cPCI bus segment at 66MHz
and a bridge side counts for a load, four bridges were
In order to allow for the RTM access
in all slots, the PCI-to-PCI bridge pallet boards need
to have a low profile such that they do not interfere
with the RTM boards.
The four PCI-to-PCI bridges cannot
be cascaded due to the latency and timing issues that
would render the backplane not functional at 66MHz.
The latency and timing issues are solved by adopting
a star configuration where the system slot situated
at the middle of the backplane is controlling four PCI-to-PCI
bridges and each bridge is controlling four peripheral
slots with the 18th unused slot attached to one of the
four cPCI segments.
The four PCI-to-PCI bridges are
placed on two pallet boards, each carrying two of them.
The pallet boards plug in the back of the backplane
using high density, low profile connectors. Each bridge
pallet spans on four slots bringing the signals at the
physical location of the first slot of each segment.
PICMG®2.16 compliant CompactPCI backplane with remote controlled switching between redundant active system slots
The 21-slots, 6U backplane is PICMG
2.16 (packet switching) compliant with 32-bit, 33MHz
CompactPCI bridged bus. The 10 peripheral cPCI slots
are RTM ready.
The backplane has two system slots
but only one of the CPU cards seated in these slots
is controlling the cPCI bus at a given time. The two
CPU boards update each other through Ethernet links
and control 10 peripheral boards through a PCI-to-PCI
bridge. If the active CPU board fails or sustains damage,
the other CPU will overtake all the functions after
a shut sown or a system reset. The cPCI signals between
the two system slots and the peripheral slots are routed
through CMOS Wide Bandwidth Quad 2:1 Muxes controlled
by one external signal driven by the system shelf manager.
Elinktron designed the backplane and the low profile
pallet board that carries the mux / switching circuitry.
The units can be deployed in remote unmanned locations.
Rigid-Flex-Rigid board for Ethernet and Audio signaling
The chassis features a front panel
that carries 16 circular connectors (see picture) and
must swing to the outside in order to allow access inside
the chassis. Around 500 mixed analog (audio) and digital
signals connect the circular connectors to the backplane
in the chassis. The remainder of the pins is assigned
to GND and +5V.
Elinktron designed a rigid-flex-rigid
board done in 12 layers for the rigid part and 8 layers
for the flex. Due to the impedance requirements each
signal flex layer refers to a GND layer such that each
of the eight flex strips consists of a set of four overlapped
dual layer Kapton strips.
Custom SATA Backplane
The backplane is based on a 3U CompactPCI
form factor and features 8 slots, SATA connectors and
three slots dedicated for pluggable power supplies.