75W x 4 @ 2Ω — the power budget drives the thermal design
The TDA7563B delivers 75W per channel into a 2Ω load across all four channels — that's 300W total output power. In a Class AB topology, dissipation at full output is roughly 50-60% of output power, so the heatsink must handle 150-180W continuous. Supply range is 8V to 18V, covering both a nominal 12V automotive bus and the 14.4V charging voltage. The 150°C junction temperature rating means the die can survive a stalled cooling fan or a summer dashboard soak, but the long-term reliability at those extremes depends on keeping the junction below 125°C in normal operation — the 75W rating assumes a heatsink that holds the case temperature below 85°C.
I²C diagnostics and protection — what the bus tells you
The I²C interface exposes diagnostic registers for short-circuit, thermal warning, and DC offset detection. On power-up, the mute pin holds the outputs quiet until the I²C bus initializes and clears the mute bit — this prevents the power-on thump from reaching the speakers. The standby mode drops quiescent current to microamps, which matters for ignition-off battery drain in automotive head units. Short-circuit protection is per-channel and latched — a fault on one output mutes that channel but leaves the other three running. The thermal protection thresholds are factory-set at 150°C (shutdown) with a 20°C hysteresis. The I²C status register reads back which channel tripped, so the system controller can log the fault or retry after a cool-down period.
Active lifecycle — no LTB clock ticking
For a BOM that needs this exact Flexiwatt footprint and pinout, the supply channel is standard distribution — no premium for EOL risk. The part is sourced to order against an RFQ through independent and authorized distribution. The ROHS3 compliance covers the full substance restriction list (including DEHP, BBP, DBP, DIBP) — no exemption declarations needed for EU market shipments.