LM4850 Datasheet | National Semiconductor

Description The LM4850 is an audio power amplifier capable of delivering 1.5W (typ) of continuous average power into a mono 4Ω bridged-tied load (BTL) with 1% THD+N or 95m W per channel of continuous average power into stereo 32Ω single-ended (SE) loads with 1% THD+N, using a 5V power supply. The LM4850 can automatically switch between mono BTL and stereo SE modes utilizing a headphone sense pin. It is ideal for any system that provides both a monaural speaker output and a stereo line or headphone output Boomer audio power amplifiers were designed specifically to provide high quality output power with a minimal amount of external ponents. Since the LM4850 does not require bootstrap capacitors or snubber networks, it is optimally suited for low-power portable systems. The LM4850 features an externally controlled, micropower consumption shutdown mode and thermal shutdown protection. The unity-gain stable LM4850’s gain is set by external gain-setting resistors Note 1: An LM4850LD that has been properly mounted to a circuit board will deliver 1.9W into 3Ω (at 1% THD+N). The other package options for the LM4850 will deliver 1.1W into 8Ω (at 1% THD+N). See Application Information sections for further information concerning the LM4850LD, LM4850MM, and LM4850MT. Key Specifications n n n n n n n n n n Output Power at 1% THD+N, 1k Hz: LM4850LD 3Ω BTL LM4850LD 4Ω BTL LM4850MM, MT 4Ω BTL LM4850LD, MM, MT 8Ω BTL LM4850LD, MM, MT 8Ω SE LM4850LD, MM, MT 32Ω SE THD+N at 1k Hz, 95m W into 32Ω SE Single Supply Operation Shutdown Current 1.9W (typ) 1.7W (typ) 1.5W (typ) 1.1W (typ) 300m W (typ) 95m W (typ) 1% (typ) 2.4 to 5.5V 44µA (typ) Features n n n n n n n Mono 1.5W BTL or stereo 300m W output Headphone sense “Click and pop” suppression circuitry No bootstrap capacitors required Thermal shutdown protection Unity-gain stable LLP, TSSOP, and MSOP packaging Applications n n n n Portable puters Desktop puters PDA’s Handheld games Typical Application FIGURE 1. Typical Audio...