Logic capacity and I/O count for BOM-fit decisions
The ICE40LP8K-CM81 integrates 7680 logic cells (960 LABs/CLBs) and 128 Kbit of block RAM, placing it in the mid-density tier of the iCE40 LP family. For a design that needs a few hundred LUTs for glue logic plus a small FIFO or register file, this device leaves headroom without overspending on a larger FPGA. 63 user I/O are brought out to the 81-ball BGA. The 4x4 mm 81-UCBGA footprint (0.5 mm pitch typical for this class) demands careful fan-out on a multi-layer board; the 63 I/O count is the practical limit for the package, not the core logic.
Core supply is 1.14 V to 1.26 V — a single 1.2 V rail suffices, simplifying the power tree.
Supplied in Tray packaging, the 81-VFBGA (81-UCBGA 4x4 mm) is a fine-pitch BGA. The 0.5 mm ball pitch requires a solder paste stencil with aperture ratios matched to the pad diameter; a standard reflow profile for lead-free SAC305 alloy is appropriate.