Cell Array. XC4003A Datasheet
® XC4000, XC4000A, XC4000H
Logic Cell Array Families
• Third Generation Field-Programmable Gate Arrays
– Abundant flip-flops
– Flexible function generators
– On-chip ultra-fast RAM
The XC4000 families of Field-Programmable Gate Arrays
(FPGAs) provide the benefits of custom CMOS VLSI, while
avoiding the initial cost, time delay, and inherent risk of a
conventional masked gate array.
– Dedicated high-speed carry-propagation circuit
– Wide edge decoders
The XC4000 families provide a regular, flexible, program-
mable architecture of Configurable Logic Blocks (CLBs),
– Hierarchy of interconnect lines
interconnected by a powerful hierarchy of versatile routing
– Internal 3-state bus capability
resources, and surrounded by a perimeter of program-
– Eight global low-skew clock or signal distribution
mable Input/Output Blocks (IOBs).
• Flexible Array Architecture
XC4000-family devices have generous routing resources to
accommodate the most complex interconnect patterns.
– Programmable logic blocks and I/O blocks
XC4000A devices have reduced sets of routing resources,
– Programmable interconnects and wide decoders
sufficient for their smaller size. XC4000H high I/O devices
• Sub-micron CMOS Process
– High-speed logic and Interconnect
maintain the same routing resources and CLB structure as
the XC4000 family, while nearly doubling the available I/O.
– Low power consumption
The devices are customized by loading configuration data
• Systems-Oriented Features
– IEEE 1149.1-compatible boundary-scan logic support
– Programmable output slew rate
– Programmable input pull-up or pull-down resistors
into the internal memory cells. The FPGA can either actively
read its configuration data out of external serial or byte-
parallel PROM (master modes), or the configuration data
can be written into the FPGA (slave and peripheral modes).
– 12-mA sink current per output (XC4000 family)
The XC4000 families are supported by powerful and so-
– 24-mA sink current per output (XC4000A and
phisticated software, covering every aspect of design: from
schematic entry, to simulation, to automatic block place-
• Configured by Loading Binary File
– Unlimited reprogrammability
ment and routing of interconnects, and finally the creation
of the configuration bit stream.
– Six programming modes
Since Xilinx FPGAs can be reprogrammed an unlimited
• XACT Development System runs on ’386/’486-type PC,
NEC PC, Apollo, Sun-4, and Hewlett-Packard 700
– Interfaces to popular design environments like
Viewlogic, Mentor Graphics and OrCAD
– Fully automatic partitioning, placement and routing
number of times, they can be used in innovative designs
where hardware is changed dynamically, or where hard-
ware must be adapted to different user applications. FPGAs
are ideal for shortening the design and development cycle,
but they also offer a cost-effective solution for production
rates well beyond 1000 systems per month.
– Interactive design editor for design optimization
– 288 macros, 34 hard macros, RAM/ROM compiler
Table 1. The XC4000 Families of Field-Programmable Gate Arrays
XC4002A 4003/3A 4003H 4004A 4005/5A 4005H 4006 4008 4010/10D 4013/13D 4020 4025
Appr. Gate Count
Number of CLBs
Number of Flip-Flops
Max Decode Inputs
Max RAM Bits
Number of IOBs
10 x 10
10 x 10
12 x 12
14 x 14
14 x 14 16 x 16
18 x 18
20 x 20
24 x 24
28 x 28
32 x 32
3,200 3,200 4,608 6,272 6,272 8,192 10,368 12,800* 18,432* 25,088 32,768
80 160 96 112 192 128 144 160 192 224 256
*XC4010D and XC4013D have no RAM
XC4000, XC4000A, XC4000H Logic Cell Array Families
XC4000 Compared to XC3000A
For those readers already familiar with the XC3000A
family of Xilinx Field Programmable Gate Arrays, here is a
concise list of the major new features in the XC4000 family.
CLB has two independent 4-input function generators.
A third function generator combines the outputs of the
two other function generators with a ninth input.
All function inputs are swappable, all have full access;
none are mutually exclusive.
CLB has very fast arithmetic carry capability.
CLB function generator look-up table can also be used as
CLB flip-flops have asynchronous set or reset.
CLB has four outputs, two flip-flops, two combinatorial.
CLB connections symmetrically located on all four edges.
IOB has more versatile clocking polarity options.
IOB has programmable input set-up time:
long to avoid potential hold time problems,
short to improve performance.
IOB has Longline access through its own TBUF.
Outputs are n-channel only, lower VOH increases speed.
XC4000 outputs can be paired to double sink current to
24 mA. XC4000A and XC4000H outputs can each
sink 24 mA, can be paired for 48 mA sink current.
IEEE 1149.1- type boundary scan is supported in the I/O.
Wide decoders on all four edges of the LCA device.
Increased number of interconnect resources.
All CLB inputs and outputs have access to most inter-
Switch Matrices are simplified to increase speed.
Eight global nets can be used for clocking or distributing
TBUF output configuration is more versatile and 3-state
control less confined.
Program is single-function input pin,overrides everything.
INIT pin also acts as Configuration Error output.
Peripheral Synchronous Mode (8 bit) has been added.
Peripheral Asynchronous Mode has improved hand-
Start-up can be synchronized to any user clock (this is a
No Powerdown, but instead a Global 3-state input that
does not reset any flip-flops.
No on-chip crystal oscillator amplifier.
Configuration Bit Stream includes CRC error checking.
Configuration Clock can be increased to >8 MHz.
Configuration Clock is fully static, no constraint on the
maximum Low time.
Readback either ignores flip-flop content (avoids need for
masking) or it takes a snapshot of all flip-flops at the
start of Readback.
Readback has same polarity as Configuration and can be
Table 2. Three Generations of Xilinx Field-Programmable Gate Array Families
Number of flip-flops
Max number of user I/O
Max number of RAM bits
Function generators per CLB
Number of logic inputs per CLB
Number of logic outputs per CLB
Number of low-skew global nets
Fast carry logic
Internal 3-state drivers
Output slew-rate control
Crystal oscillator circuit
The XC4000 families achieve high speed through ad-
vanced semiconductor technology and through improved
architecture, and supports system clock rates of up to 50
MHz. Compared to older Xilinx FPGA families, the XC4000
families are more powerful, offering on-chip RAM and
wide-input decoders. They are more versatile in their
applications, and design cycles are faster due to a combi-
nation of increased routing resources and more sophisti-
cated software. And last, but not least, they more than
double the available complexity, up to the 20,000-gate
The XC4000 families have 16 members, ranging in com-
plexity from 2,000 to 25,000 gates.
Logic Cell Array Families
Xilinx high-density user-programmable gate arrays in-
clude three major configurable elements: configurable
logic blocks (CLBs), input/output blocks (IOBs), and inter-
connections. The CLBs provide the functional elements
for constructing the user’s logic. The IOBs provide the
interface between the package pins and internal signal
lines. The programmable interconnect resources provide
routing paths to connect the inputs and outputs of the CLBs
and IOBs onto the appropriate networks. Customized
configuration is established by programming internal static
memory cells that determine the logic functions and inter-
connections implemented in the LCA device.
The first generation of LCA devices, the XC2000 family,
was introduced in 1985. It featured logic blocks consisting
of a combinatorial function generator capable of imple-
menting 4-input Boolean functions and a single storage
element. The XC2000 family has two members ranging in
complexity from 800 to 1500 gates.
In the second-generation XC3000A LCA devices, intro-
duced in 1987, the logic block was expanded to implement
wider Boolean functions and to incorporate a second flip-
flop in each logic block. Today, the XC3000 devices range
in complexity from 1,300 to 10,000 usable gates. They
have a maximum guaranteed toggle frequency ranging
from 70 to 270 MHz, equivalent to maximum system clock
frequencies of up to 80 MHz.
The third generation of LCA devices further extends this
architecture with a yet more powerful and flexible logic
block. I/O block functions and interconnection options
have also been enhanced with each successive genera-
tion, further extending the range of applications that can be
implemented with an LCA device.
This third-generation architecture forms the basis of the
XC4000 families of devices that feature logic densities up
to 25,000 usable gates and support system clock rates of
up to 50 MHz. The use of an advanced, sub-micron CMOS
process technology as well as architectural improvements
contribute to this increase in FPGA capabilities. However,
achieving these high logic-density and performance levels
also requires new and more powerful automated design
tools. IC and software engineers collaborated during the
definition of the third-generation LCA architecture to meet
an important performance goal — an FPGA architecture
and companion design tools for completely automatic
placement and routing of 95% of all designs, plus a
convenient way to complete the remaining few designs.
Configurable Logic Blocks
A number of architectural improvements contribute to the
increased logic density and performance levels of the
XC4000 families. The most important one is a more
powerful and flexible CLB surrounded by a versatile set of
routing resources, resulting in more “effective gates per
CLB.” The principal CLB elements are shown in Figure 1.
Each new CLB also packs a pair of flip-flops and two
independent 4-input function generators. The two function
generators offer designers plenty of flexibility because
most combinatorial logic functions need less than four
inputs. Consequently, the design-software tools can deal
with each function generator independently, thus improv-
ing cell usage.
Thirteen CLB inputs and four CLB outputs provide access
to the function generators and flip-flops. More than double
the number available in the XC3000 families, these inputs
and outputs connect to the programmable interconnect
resources outside the block. Four independent inputs are
provided to each of two function generators (F1 – F4 and
G1 – G4). These function generators, whose outputs are
labeled F' and G', are each capable of implementing any
arbitrarily defined Boolean function of their four inputs. The
function generators are implemented as memory look-up
tables; therefore, the propagation delay is independent of
the function being implemented. A third function genera-
tor, labeled H', can implement any Boolean function of its
three inputs: F' and G' and a third input from outside the
block (H1). Signals from the function generators can exit
the CLB on two outputs; F' or H' can be connected to the
X output, and G' or H' can be connected to the Y output.
Thus, a CLB can be used to implement any two independ-
ent functions of up-to-four variables, or any single function
of five variables, or any function of four variables together
with some functions of five variables , or it can implement
even some functions of up to nine variables. Implementing
wide functions in a single block reduces both the number
of blocks required and the delay in the signal path, achiev-
ing both increased density and speed.
The two storage elements in the CLB are edge-triggered
D-type flip-flops with common clock (K) and clock enable
(EC) inputs. A third common input (S/R) can be pro-
grammed as either an asynchronous set or reset signal