STK8040 Integrated Circuit

Quick and frank summary: the “STK8040” is a Sanyo audio power hybrid module, but the official datasheet is rare/hard to source; much of the circulating information comes from service manuals of equipment that employs it.

Indicative data (inferred from known applications of that era/family, to be verified against the original datasheet):

• Configuration: class AB audio amplifier, 2 channels (stereo)
• Output power: typically 2 × 20–30 W into 8 Ω (THD 0.3–1% at 1 kHz)
• Power supply: symmetrical, typically ±22…±25 V; maximum limit around ±30…±33 V
• Recommended load: ≥ 8 Ω
• Frequency response: about 20 Hz – 20 kHz (±1 dB, indicative)
• THD: ~0.1–0.5% at rated power (typical for the family)
• Input sensitivity: ~0.7–1 Vrms for Pnom (indicative)
• Slew rate and damping factor: in line with other contemporary STKs (not documented with certainty)
• Package: SIP hybrid module with rear metal plate for heatsink; pin count 15–18 depending on the variant