30W per channel into 8Ω — what the output rating means for your speaker load
The TPA3128D2DAPR delivers 30W x 2 into an 8Ω load per channel — that is the continuous sine-wave power before clipping, not a peak music-power number. For a typical bookshelf or ceiling speaker with 8Ω nominal impedance and 87 dB sensitivity, each channel drives to about 102 dB SPL at 1 m, enough for a small room or distributed audio zone. Class D topology means the output stage switches at high frequency (typically 400-500 kHz internal oscillator) rather than dissipating heat linearly.
4.5V to 26V supply — wide-rail flexibility for automotive, industrial, and consumer rails
The 4.5V minimum supply means the amplifier runs from a single lithium-ion cell (3.7V nominal plus boost) or a 5V USB rail with headroom. The 26V maximum covers a 24V industrial supply with tolerance and a 12V automotive battery during charge (up to 14.4V) with margin. No external pre-regulator needed for most common rails.
Package and thermal — the exposed-pad layout requirement
The 32-TSSOP with exposed pad (0.240", 6.10 mm width) requires the PCB land pattern to include a thermal pad on the top copper layer matching the package's exposed die-attach paddle. The datasheet recommends a 4.5 mm x 4.5 mm pad with at least nine thermal vias (0.3 mm diameter) to the ground plane on layer 2. Without this via array, the thermal resistance RθJA rises from about 35°C/W to over 60°C/W, and the part thermally limits output power at 85°C ambient. The package is surface-mount only — no through-hole variant. The 0.65 mm lead pitch is standard for TSSOP; a fine-tip soldering iron or reflow profile with peak 260°C works for rework. The exposed pad must be soldered, not just thermally coupled with grease — the electrical connection to the ground plane also carries the output return current.
Short-circuit protection — output fault handling without external components
The TPA3128D2DAPR includes short-circuit protection on the output stage — if a speaker wire shorts to ground or to the opposite channel, the amplifier shuts down the offending channel and auto-recovers after a thermal cool-down period. No external fuse or crowbar circuit required for the output stage, though the supply input should still have a bulk capacitor (typically 1000 µF per channel) to handle the inrush during recovery.