84,000 logic elements in a 17×17 mm footprint
The LFE5U-85F-6BG381C is a Lattice ECP5 FPGA packing 84,000 logic elements and 21,000 LABs/CLBs into a 381-ball CABGA package measuring 17×17 mm. The 3.8 Mbit block RAM gives you room for moderate-size FIFOs, line buffers, or coefficient tables without reaching for external memory. With 205 user I/O in that ball count, the I/O-to-logic ratio leans toward logic-heavy designs — think image-sensor interfaces, motor-control loops, or bridge functions where the gate count matters more than the pin count.
Core supply and temperature grade — the design constraints
The core voltage rail is 1.045 V to 1.155 V — a tight 110 mV window that demands a clean 1.1 V regulator with good transient response. The operating temperature range is 0°C to 85°C, so this part is rated for commercial/industrial indoor environments, not extended or automotive.
Sourcing and cross-reference reality
This is a single-source Lattice part — no official second-source or pin-compatible alternative from another vendor. The closest peer in the same 381-CABGA footprint is the LFE5UM-45F-8BG381C, which halves the logic to 44,000 elements and the block RAM to 2 Mbit, but keeps the same 203 I/O and supply voltage. If your design was originally specified around the 45K variant and you need more headroom, the LFE5U-85F-6BG381C drops into the same PCB footprint without a board spin — the ball map is identical.