0.35
Gate Arrays
Features
Five array sizes:
24,000 to 2M gates
68 to 680 pads
3.3 volt operation
Flexible pin assignments
Conversion from FPGAs, PLDs, and ASICs,
(including other gate arrays)
Low power dissipation
High gate utilization
Sea-of-Gates architecture
Functional logic equivalent guaranteed
D A T A S H E E T
Description
Flextronics Semiconductor's 0.35
family
of gate arrays provides retargeting
solutions for FPGA and Gate Array
conversions.
The Encore!
Plus program is a retargeting
service featuring direct replacement of
FPGAs, PLDs, and ASICs, including other
Gate Arrays, using Flextronics
Semiconductor's 0.35
Gate Array
technology. In most cases no new tools
are required to take advantage of this
service. Encore!
Plus offers low-NRE, fast-
turnaround cycle times and flexible
manufacturing.
Flextronics Semiconductor's gate arrays
use a sea-of-gates architecture with a
novel gate design which allows high
utilization while minimizing the effect of
interconnect capacitance on circuit
performance. Since gate arrays are
personalized with the last few processing
masks, a fast response time to customer
orders can be made, allowing the
customer more options in circuit
definition.
These gate arrays offer significant
flexibility in pin definition. Contrary to
designing with FPGAs, the customer can
define any pin to be any signal function or
power supply. The Encore!
Plus program
allows customers to redefine any pin's
electrical parameters. Customers may
select their choice of pin characteristics,
such as output drive levels, slew rate
control, different input switching points
and hysteresis.
All prototypes are not only fully tested
prior to shipment, but are assembled in
the production package on the production
line. This allows the customer to use
prototypes as if they were production
parts.
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D A T A S H E E T
0.35
Gate Arrays
Name
Gates
Gates
1
# of Pins
Base_68
29,900
24,000
68
Base_100
66,300
53,000
100
Base_208
318,000
160,000
208
Base_320
524,000
420,000
320
Base_680
2,400,000
2,000,000
680
Flextronics Semiconductor's 0.35
Gate Array Family
The 0.35
gate array family currently consists of
five arrays, and new arrays can be added as the
need arises. Table 1 provides examples of the
current arrays, their size and the number of pins.
These gate arrays have been designed with a
maximum number of power and I/O pads. This
allows Flextronics Semiconductor to offer the most
cost-effective array size, especially in those cases
where the design is limited by the number of I/O
connections, rather than by the number of gates.
Table 1. Flextronics Semiconductor's
0.35
Gate Arrays
can be added, and there is also an optional pull-up or
pull-down resistor.
Outputs vary by strength. Output strengths from
2 mA to 24 mA may be specified individually for each
pin. Higher currents may be obtained by paralleling
I/O pads.
The control logic for the outputs allows an output to
be continuous, tristate or open-drain. Slew rate
control is added on all outputs whose strength is in
excess of 8 mA. Flextronics Semiconductor's gate
array family also supports open-drain outputs with a
dynamic precharge for extra system speed.
Any output may be combined with any input to create
a bi-directional I/O buffer with a choice of
characteristics.
Power Pins
Flextronics Semiconductor's gate arrays have been
designed to act as a replacement for many existing
gate arrays and FPGAs. This means that the internal
power busses are designed to be strong enough to
support other vendors' rules on the number of supply
pins necessary to support a given number and
strength of outputs.
For new designs, the number of power pins required
is a trade-off between the number of pins available
and the ability of the PC board to provide a clean, low-
inductance supply.
Flextronics Semiconductor can skew simultaneous
switching outputs upon request. We also add slew rate
controls to all high-power outputs to minimize the
peak currents associated with output switching.
Flextronics Semiconductor recommends replacing
some or all no-connect pins with supply pins, as a
means of increasing the amount of margin within the
design.
Special Requests
Flextronics Semiconductor's gate arrays are made up
of uncommitted transistors, and there are no arbitrary
limits as to how these transistors may be used. We will
create specific functions upon request.
Flextronics Semiconductor can provide circuitry to
support PCI, JTAG, crystal oscillators, RC oscillators,
current mirrors, etc. and the libraries include a variety
of synthesizable cores.
Typ. Used
Pin Assignment
Flextronics Semiconductor's gate arrays have been
designed so that any pin may be assigned any input/
output (I/O) function, including power and ground.
This flexibility allows gate arrays to match any
existing pinout, creating an exact replacement for
either FPGAs, PLDs, or ASICs, (including gate arrays).
The internal power supply busses are designed to
prevent any output switching transients from
affecting the internal logic.
I/O Capability
The gate array family I/O buffers are designed so that
only the guard-banded, output drive transistors and
the pull-up
/pull-down transistors are dedicated to a
specific pin. All of the output control logic and the
input level translators are built from internal array
transistors. Since these internal transistors are not
dedicated to a specific buffer, a number of different
I/O functions may be created.
Input buffers may be designed to work with either
CMOS or TTL levels. In either case, a Schmitt trigger
Note: 1. Actual gate utilization is design-dependent.
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D A T A S H E E T
0.35
Gate Arrays
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Design Conversions
For netlist conversions, Flextronics Semiconductor
supports multiple formats and industry-standard
tools.
To convert a customer's design, Flextronics
Semiconductor needs a netlist of the circuit, vectors
and a pinout. Additional information, such as the
timing of a critical path, may be supplied if such a
path needs additional evaluation.
Netlists
A netlist defines the logic to be implemented in the
gate array. While most gate-level formats are
acceptable to the Encore!
Plus program, the netlist
must be in ASCII format. Most binary netlists are
proprietary and undocumented, which prevents
Flextronics Semiconductor from translating them.
Examples of acceptable netlist formats include:
XNF
(Xilinx)
EDIF
(Altera, others)
ADL
(Actel)
LDL
(LSI Logic)
TDL
(Toshiba)
QDF
(QuickLogic)
Wire File
(ViewLogic)
Simulations
Flextronics Semiconductor prefers simulations at
1 MHz are supplied by the customer. In the event
that simulations are not available, assistance in the
development of simulation vectors can be provided.
Flextronics Semiconductor provides a service to
enhance test vectors using methods such as ATPG
and SCAN.
Flextronics Semiconductor uses the customer's
vectors to confirm that the design has been correctly
converted into the Flextronics Semiconductor
format, and to develop the production test vectors.
Using low-speed simulations makes it easier to verify
the functionality of the logic. High-speed simulations,
particularly with FPGAs, often produce vectors with
signals which take more than one clock cycle to
propagate to the output. Such vectors make it
difficult to verify a correct design conversion.
Flextronics Semiconductor will evaluate and confirm
higher speed simulations upon request.
The preferred format for simulations is to show every
signal pin in a table, with the simulation output in a
"Print-On-Change" format. This supplies significant
information to Flextronics Semiconductor engineering
about the expected device performance. Table 2
shows a Print-on-Change format for an exclusive-OR
(XOR) gate.
Table 2. Print-On-Change Format (XOR)
Time
A
B
O
0 ns
0
0
0
50 ns
0
1
0
52 ns
0
1
1
100 ns
1
0
1
150 ns
1
1
1
153 ns
1
1
0
Pin List
Flextronics Semiconductor requires a listing of pin
numbers, pin names and the function and/or
specifications for the input and output pins. This list
should include any special characteristics that the pin
must have, such as TTL-level input or open-drain
output. The pin list also provides customers with a
means to modify the I/O characteristics normally
associated with FPGA netlists. The default is to use the
I/Os specified by the original FPGA manufacturer. By
referencing different specifications in the pin file, the
customer can obtain any desired I/O characteristics.
Table 3 lists some typical pinout specifications
Pin
Name
Specification
1
CLK
Input - TTL
2
IOR
Input - TTL
3
IOW
Input - TTL
4
PS3
Input - CMOS w/10K pull-up resistor
5
CS
Input - CMOS w/10K pull-up resistor
6
VDD
Supply
7
DATA0
Bidirectional - 12 mA
8
VSS
Supply
9
RMS
Input - TTL
10
DATA1
Bidirectional - 12 mA
11
--
No Connect
12
VSS
Supply
13
OSC#IN
Input - TTL
14
OSC#OUT Output - 6 mA
15
OSCBUF
Output - 6 mA
16
VDD
Supply
Table 3. Pinout Specifications
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D A T A S H E E T
0.35
Gate Arrays
Implementing Designs
Flextronics Semiconductor's approach is based
on the concept of transferring a design
implemented in a given technology to
Flextronics Semiconductor gate arrays. We
perform the conversion and execute a number
of checks on the design.
Flextronics Semiconductor provides production-
ready ASICs. Customers can design a true ASIC
while benefiting from all FPGA advantages (quick
turnaround of prototypes, fast time to market,
low NRE, no volume commitment) without the
associated penalties (high cost, routing, pin and
footprint constraints, and limited package
selections).
A customer can first synthesize the netlist into
an FPGA to validate the design concept, then
synthesize to Flextronics Semiconductor gates to
obtain:
Significantly lower cost
No risk
Access to arrays with up to 2.4M gates
Low NRE and quick turns
Access to analog cells
Flextronics Semiconductor will support
customers with these application issues:
Optimize synthesis results (smallest silicon
area, best timing)
HDL simulation
Static Timing analysis (pre- and post-layout)
Pin configuration (ground-bounce issues)
The Flextronics Semiconductor design engineer
converts the customer's netlist into the
Encore!
Plus format. The procedure varies,
depending upon the type and source of the
netlist. Flextronics Semiconductor uses a
collection of proprietary and commercially
available translators.
An appropriate cross reference library is used to
generate the converted netlist. This library
reflects all the primitives used by the customer
in terms of Flextronics Semiconductor
primitives.
After the netlist has been converted, Flextronics
Semiconductor runs a design analysis program
which determines the size of the circuit and
looks for loading violations. Any violations
discovered are fixed by either increasing the
strength of the signal driver or by buffering the
signal.
Particular attention is paid to the clock structure.
The preferred clock organization is a single clock
which goes to all flip flops. In this case,
Flextronics Semiconductor designs a special
clock driver that is matched to the load.
Timing-driven layout automatically compensates
for variations in loading and balances the clock
tree. Clock skew is rechecked during the "five
corner" simulation runs.
Our designer converts the simulation output into
an input stimulus for Flextronics
Semiconductor's internal simulator.
Initial Verification
Using a typical library, the Flextronics
Semiconductor design engineer runs a
simulation on the converted netlist and
compares the results to the customer-supplied
simulation. Usually, the results match. If they do
not, the engineer determines the reason and
works with the customer for an acceptable
solution. A common cause for mismatches is
race conditions introduced during the
conversion process.
Design Checks
Once Flextronics Semiconductor has verified
that the design has been correctly converted, a
series of checks is done. Principal among these
checks is a "five corner" simulation. This
consists of a set of five simulation runs, each
run with a different timing library. These libraries
cover the traditional best, typical, and worst
case conditions. They also cover the cases of
best rise times combined with the worst fall
times, and the worst rise times combined with
the best fall times. These last two cases are
especially severe, and will generally cause a
circuit failure if there is any weakness in the
design.
In each of these simulations, Flextronics
Semiconductor checks the setup and hold times
for every flop in the circuit.
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D A T A S H E E T
0.35
Gate Arrays
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Flextronics Semiconductor's Gate
Array Packaging
The small size of Flextronics Semiconductor's
gate arrays allows considerable flexibility in
choosing a package. This is particularly relevant
when dealing with an FPGA conversion, in that
the large FPGA die size frequently limits package
availability.
As a general rule, any commercially available
package may be used with the gate array family,
subject only to the requirement that the gate
array must fit in the package cavity.
The customer may select either the original
package type or an alternate one. Frequently,
FPGA conversions can be implemented in a
smaller package which can present considerable
savings, both in board space and in unit cost.
Table 4 is a partial list of package styles which
are supported by Flextronics Semiconductor.
Please contact us for your packaging specification
and for various lead-length options.
Table 4. Commonly Used Packages
Package
1
Pins
Max. Base Size
PLCC
28
Base_100
PLCC
44
Base_100
PLCC
68
Base_100
PLCC
84
Base_100
QFP
100
Base_100
QFP
144
Base_208
QFP
160
Base_208
QFP
208
Base_680
QFP
240
Base_680
BGA
225
Base_680
BGA
352
Base_ 680
BGA
432
Base_680
BGA
672
Base_680
Note: 1. These are examples of commonly used packages. Virtually
any commercially available package may be used.
Marking
The default marking scheme uses five lines of
16 characters each. The first three are defined
by the customer. The last two lines are
Flextronics Semiconductor's part number and
the date code, indicating when the packaging
was done.
Parts may also be marked with customer-
supplied graphics. For your particular needs,
please consult the factory.
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