4 Mbit asynchronous SRAM in a 48-VFBGA — what the 45 ns access time means on the bus
The Cypress CY62146EV30LL-45BVXIT is a 4 Mbit asynchronous SRAM from the MoBL® series, organized as 256K x 16 bits with a parallel interface. It operates from a 2.2 V to 3.6 V supply and is rated for the industrial temperature range of -40°C to 85°C (TA). The 45 ns access time is the key timing parameter: it sets the window from address valid to data valid on a read cycle. For a processor running at, say, 20 MHz with a 50 ns bus cycle, this part fits with zero wait states — but at 33 MHz (30 ns cycle) you need to check the address-to-data setup against the controller's tACC requirement. The part is housed in a 48-VFBGA (6x8 mm) package, a fine-pitch BGA that demands careful PCB fanout and a controlled reflow profile.
Package and layout — 48-VFBGA fanout and decoupling
The 48-VFBGA (6x8 mm) package has a 0.5 mm ball pitch. That means via-in-pad or microvia fanout is the practical route for a two-layer board; a four-layer stackup with blind vias makes routing cleaner. Place a 0.1 µF ceramic decoupling capacitor within 2 mm of each supply ball pair, and a 4.7 µF bulk cap near the BGA perimeter. The package is MSL 3 — bake at 125°C for 8 hours if the moisture-barrier bag has been open longer than the floor-life window. Reflow profile per JEDEC J-STD-020, peak temperature 260°C.
Lifecycle and compliance
It is ROHS3 compliant, with no halogenated flame retardants or phthalates in the package.