Class G topology and output power — what 2.4W into 8Ω means for the speaker load
The MAX9788EWP+TG45 is a Class G mono amplifier delivering 2.4W into an 8Ω load from a 2.7V to 5.5V supply. Class G uses a dual-rail or switched-rail architecture that steps the supply voltage to the output stage, keeping the voltage drop across the output devices lower than a fixed-rail Class AB — this cuts quiescent current draw in half at low signal levels, which matters for battery-powered portable audio where the amplifier spends most of its time below 100 mW. The 2.4W figure is the maximum continuous output into an 8Ω speaker before clipping. At 3.7V (nominal Li-ion), expect roughly 1.7W into 8Ω — still enough for a loudspeaker in a Bluetooth speaker or a portable dock. The differential inputs reject common-mode noise picked up on long PCB traces or flex cables from the codec output.
Package and board-fit — 20-WLP with 0.4mm pitch
The MAX9788EWP+TG45 comes in a 20-WFBGA (WLBGA) package, also referred to as 20-WLP. The ball pitch is 0.4 mm — standard for a WLP of this I/O count. The PCB land pattern requires a soldermask-defined pad with a 0.25 mm NSMD opening; the stencil aperture should be 0.28 mm square with a 100 µm thickness to get the right solder volume for the 0.25 mm solder ball. No thermal pad — the die dissipates heat through the balls and the PCB copper plane on the top layer. The TG45 suffix indicates the tape-and-reel format with a 7-inch reel. For hand-assembly or rework, the cut-tape variant is the one to order — the reel variant is for pick-and-place lines. The WLP has no exposed die paddle, so the reflow profile follows the standard JEDEC J-STD-020 for a 0.4 mm pitch BGA: peak temperature 245°C, ramp rate 3°C/s max.
Active lifecycle and compliance — no end-of-life risk
The part is ROHS3 compliant (lead-free, no exemptions), which covers EU RoHS and most global regulatory requirements.