The XC4085XLA-07HQ240C is a high-density, low-voltage field-programmable gate array (FPGA) from Xilinx’s XC4000XLA family. Designed for demanding digital logic applications, this device offers 85,000 system gates, a 240-pin HQFP package, and operates at the extended commercial temperature range. It is widely used in telecommunications, industrial control, data processing, and embedded system designs. If you are looking for a reliable Xilinx FPGA for your next project, the XC4085XLA-07HQ240C is a strong candidate.
XC4085XLA-07HQ240C Key Specifications at a Glance
| Parameter |
Value |
| Part Number |
XC4085XLA-07HQ240C |
| Manufacturer |
Xilinx (now AMD) |
| Series |
XC4000XLA |
| Logic Gates (Equivalent) |
85,000 |
| Configurable Logic Blocks (CLBs) |
1,296 |
| Logic Cells |
~3,136 |
| Maximum User I/O Pins |
166 |
| Package Type |
HQFP (Heat Slug Quad Flat Pack) |
| Pin Count |
240 |
| Speed Grade |
-07 |
| Supply Voltage (VCC) |
3.3 V |
| Operating Temperature |
0°C to +85°C (Commercial) |
| Technology |
SRAM-based reprogrammable |
| Programming Interface |
JTAG (IEEE 1149.1) / Serial / Parallel |
What Is the XC4085XLA-07HQ240C?
The XC4085XLA-07HQ240C belongs to Xilinx’s XC4000XLA product line — an advanced generation of the classic XC4000 FPGA architecture optimized for lower voltage (3.3 V) and improved performance. The “XLA” designation indicates the extended low-power, low-voltage variant, offering better speed performance compared to the original XC4000E and XC4000XL families.
The device is built on an SRAM-based reprogrammable fabric, meaning the configuration is loaded into internal SRAM cells at power-up and can be reprogrammed an unlimited number of times. This makes it ideal for prototyping, field upgrades, and production systems where in-circuit reconfiguration is required.
XC4085XLA-07HQ240C Part Number Breakdown
Understanding the part number helps engineers quickly decode the device’s core attributes:
| Segment |
Meaning |
| XC |
Xilinx FPGA |
| 4085 |
85,000 equivalent gate count (XC4000 series) |
| XLA |
Extended Low-power, Low-voltage Architecture (3.3 V optimized) |
| 07 |
Speed grade (-07 ns internal delay) |
| HQ |
HQFP package (Heat Slug Quad Flat Pack) |
| 240 |
240 total pins |
| C |
Commercial temperature range (0°C to +85°C) |
XC4085XLA-07HQ240C Detailed Electrical Characteristics
Power Supply and Voltage Requirements
| Parameter |
Min |
Typical |
Max |
Unit |
| Core Supply Voltage (VCCINT) |
3.0 |
3.3 |
3.6 |
V |
| I/O Supply Voltage (VCCIO) |
3.0 |
3.3 |
3.6 |
V |
| Input High Voltage (VIH) |
2.0 |
— |
VCCIO + 0.5 |
V |
| Input Low Voltage (VIL) |
−0.5 |
— |
0.8 |
V |
| Output High Voltage (VOH) |
2.4 |
— |
— |
V |
| Output Low Voltage (VOL) |
— |
— |
0.4 |
V |
Timing Characteristics (Speed Grade -07)
| Parameter |
Value |
Unit |
| Minimum CLB-to-CLB Propagation Delay |
7.0 |
ns |
| Typical System Clock Frequency |
~80–100 |
MHz |
| Maximum Setup Time (Flip-Flop) |
~3.5 |
ns |
| Maximum Hold Time (Flip-Flop) |
0 |
ns |
| Output Pad Delay |
~4.0 |
ns |
XC4085XLA Architecture and Logic Resources
#### Configurable Logic Blocks (CLBs)
The XC4085XLA-07HQ240C contains 1,296 CLBs arranged in a symmetric array. Each CLB includes:
- Two 4-input look-up tables (LUTs) — F and G functions
- One 3-input function generator (H function) combining F, G, and DIN
- Two edge-triggered D flip-flops with independent clock enable
- Fast carry logic for efficient arithmetic operations
- Internal tri-state buffers
#### Block RAM and Distributed RAM
| Resource Type |
Details |
| Distributed RAM (using LUTs) |
Up to ~25 Kbits (from CLB LUTs) |
| Dedicated Block RAM |
Not available (XC4000XLA relies on distributed RAM) |
| Shift Register Support |
Via CLB flip-flops and LUTs |
#### I/O Architecture
| I/O Feature |
Details |
| Maximum User I/O |
166 |
| I/O Standards Supported |
LVTTL, LVCMOS33 |
| Output Drive Strength |
Selectable (2 mA, 4 mA, 6 mA, 8 mA, 12 mA, 16 mA, 24 mA) |
| Slew Rate Control |
Fast / Slow |
| Pull-up / Pull-down |
Programmable per I/O |
| 3-State Output Control |
Per I/O |
XC4085XLA-07HQ240C Package Information – 240-Pin HQFP
The HQ240 (Heat Slug Quad Flat Pack) package is a 240-pin surface-mount plastic quad flat pack with a central heat slug for improved thermal performance. This package is well-suited for high-density PCB designs.
| Package Parameter |
Value |
| Package Type |
HQFP (Plastic Quad Flat Pack with Heat Slug) |
| Total Pin Count |
240 |
| I/O Pin Count (User) |
166 |
| Body Size |
36 mm × 36 mm |
| Pitch |
0.5 mm |
| Lead Finish |
Tin-Lead (SnPb) or RoHS-compliant (check suffix) |
| Mounting Type |
Surface Mount (SMD) |
| Height (Seated) |
~3.8 mm |
Configuration and Programming Modes
The XC4085XLA-07HQ240C supports multiple configuration modes, providing flexibility for different system designs:
| Configuration Mode |
Description |
| Master Serial |
FPGA drives the configuration clock; loads from serial PROM |
| Slave Serial |
External source drives configuration clock and data |
| Master Parallel (x8) |
FPGA loads from 8-bit parallel EPROM/Flash |
| Slave Parallel (x8) |
External processor downloads configuration data |
| Peripheral (x8) |
Microprocessor-controlled byte-wide configuration |
| JTAG (IEEE 1149.1) |
Boundary scan and in-circuit programming via JTAG port |
The device stores its configuration in volatile SRAM cells, so a configuration source (such as a serial PROM like the XC17S series or a microcontroller) must reload it at every power-up.
XC4085XLA vs. Similar Xilinx FPGAs – Comparison Table
| Feature |
XC4036XLA |
XC4062XLA |
XC4085XLA |
XC4085XL |
| Equivalent Gates |
36,000 |
62,000 |
85,000 |
85,000 |
| CLBs |
576 |
1,024 |
1,296 |
1,296 |
| Max User I/O |
128 |
160 |
166 |
166 |
| Core Voltage |
3.3 V |
3.3 V |
3.3 V |
3.3 V |
| Speed Grade Range |
-09 to -07 |
-09 to -07 |
-09 to -07 |
-10 to -08 |
| Technology |
SRAM |
SRAM |
SRAM |
SRAM |
| Architecture Gen |
XLA (improved) |
XLA (improved) |
XLA (improved) |
XL |
The XC4085XLA outperforms the standard XL variant in speed and power efficiency, making it the preferred choice for performance-critical designs.
Typical Applications of the XC4085XLA-07HQ240C
The XC4085XLA-07HQ240C is used across a broad range of industries and application types:
| Application Domain |
Use Case Examples |
| Telecommunications |
Protocol bridges, line cards, framing logic, signal routing |
| Industrial Automation |
Motor drive control, PLC interfaces, sensor data processing |
| Data Acquisition |
High-speed ADC/DAC interfacing, custom data pipelines |
| Embedded Systems |
Co-processing, custom peripherals, glue logic |
| Medical Devices |
Signal processing, device interfacing, diagnostics |
| Video Processing |
Frame buffers, image pipeline control |
| Prototyping & R&D |
ASIC emulation, algorithm validation, rapid iteration |
XC4085XLA-07HQ240C Design Considerations
#### PCB Layout Guidelines
- Use a 4-layer or 6-layer PCB with dedicated power and ground planes.
- Place 100 nF decoupling capacitors on every VCC/GND pair, as close to the device as possible.
- Add 10 µF bulk capacitors near the power supply pins.
- Keep configuration pins (CCLK, DIN, PROGRAM, DONE, INIT) away from high-speed signal traces.
- Use controlled-impedance traces (50 Ω) for critical high-speed I/O lines.
#### Power Sequencing
- The XC4085XLA does not require a specific power sequencing order, but it is good practice to ramp VCCINT before or simultaneously with VCCIO.
- The device will hold its outputs in tri-state until DONE goes high after successful configuration.
#### Thermal Management
- The HQFP heat slug should be soldered to a thermal pad on the PCB for optimal heat dissipation.
- Typical junction-to-ambient thermal resistance (θJA) is approximately 25–35°C/W depending on airflow.
Development Tools and Software Support
Xilinx provides comprehensive software support for the XC4000XLA family:
| Tool |
Purpose |
| Xilinx ISE Design Suite |
Synthesis, implementation, place & route, bitstream generation |
| XST (Xilinx Synthesis Technology) |
RTL synthesis from VHDL/Verilog |
| PACE |
Pin and area constraint editor |
| ChipScope Pro |
On-chip logic analysis and debugging |
| iMPACT |
Configuration file download and JTAG programming |
| ModelSim / ISim |
HDL behavioral and timing simulation |
Note: The XC4000XLA family is supported in Xilinx ISE 14.7 (the final ISE release). It is not supported in Vivado. Designers should use ISE 14.7 for all design flows targeting this device.
Ordering Information and Product Variants
The XC4085XLA is available in multiple speed grades and temperature options:
| Part Number |
Speed Grade |
Package |
Temperature |
| XC4085XLA-07HQ240C |
-07 (fastest) |
HQ240 |
Commercial (0°C to +85°C) |
| XC4085XLA-08HQ240C |
-08 |
HQ240 |
Commercial (0°C to +85°C) |
| XC4085XLA-09HQ240C |
-09 (standard) |
HQ240 |
Commercial (0°C to +85°C) |
| XC4085XLA-07HQ240I |
-07 (fastest) |
HQ240 |
Industrial (−40°C to +100°C) |
| XC4085XLA-09HQ240I |
-09 |
HQ240 |
Industrial (−40°C to +100°C) |
The -07 speed grade, as in the XC4085XLA-07HQ240C, is the fastest commercially available variant, offering the shortest propagation delays for timing-critical designs.
Frequently Asked Questions (FAQ)
Q: Is the XC4085XLA-07HQ240C RoHS compliant? A: The standard “C” suffix does not guarantee RoHS compliance. RoHS-compliant versions are typically identified with a separate suffix or tray marking. Verify with your distributor.
Q: Can I use the XC4085XLA-07HQ240C with a 5 V system? A: The device core operates at 3.3 V. I/O pins are not 5 V tolerant by default. Use level-shifting buffers when interfacing with 5 V logic.
Q: What configuration PROM should I use? A: Xilinx XC17S series serial PROMs (e.g., XC17S150) are recommended for Master Serial configuration.
Q: Is Vivado compatible with the XC4085XLA-07HQ240C? A: No. Use Xilinx ISE Design Suite 14.7, which is the last version to support the XC4000 family.
Q: What is the maximum system clock frequency? A: With the -07 speed grade, practical system clock frequencies of 80–100 MHz are achievable for typical designs with registered I/O. Actual performance depends on design complexity and place-and-route results.
Summary
The XC4085XLA-07HQ240C is a mature, proven FPGA device offering 85,000 gates, 1,296 CLBs, and 166 user I/O pins in a compact 240-pin HQFP package. With its -07 speed grade, 3.3 V operation, and commercial temperature rating, it strikes a strong balance between performance, capacity, and cost. Its support for multiple configuration modes — including JTAG, serial, and parallel — makes it adaptable to virtually any system architecture. Engineers working on telecommunications, industrial control, embedded, or data processing designs will find the XC4085XLA-07HQ240C a versatile and capable solution from the trusted Xilinx XC4000XLA platform.
