LM4985 Datasheet | National Semiconductor

Description The LM4985 is a stereo audio power amplifier with internal digitally controlled volume control. This amplifier is capable of delivering 68m WRMS per channel into a 16Ω load or 38m WRMS per channel into a 32Ω load at 1% THD when powered by a 3.6V power supply and operating in the OCL mode. Boomer audio power amplifiers were designed specifically to provide high quality output power with a minimal amount of external ponents. To that end, the LM4985 features two functions that optimize system cost and minimize PCB area: an integrated, digitally controlled (I2C bus) volume control and an operational mode that eliminates output signal coupling capacitors (OCL mode). Since the LM4985 does not require bootstrap capacitors, snubber networks, or output coupling capacitors, it is optimally suited for low-power, battery powered portable systems. For added design flexibility, the LM4985 can also be configured for single-ended capacitively coupled outputs. The LM4985 features a current shutdown mode for micropower dissipation and thermal shutdown protection. Key Specifications (VDD = 3.6V) j PSRR: 217Hz and 1k Hz Output Capacitor-less (OCL) f RIPPLE = 217Hz f RIPPLE = 1k Hz Capacitor Coupled (C-CUPL) f RIPPLE = 217Hz f RIPPLE = 1k Hz j Output Power per channel 77d B (typ) 76d B (typ) 63d B (typ) 62d B (typ) (f IN = 1k Hz, THD+N = 1%), RL = 16Ω,OCL VDD = 2.5V VDD = 3.6V VDD = 5.0V j THD+N (f = 1k Hz) 31m W (typ) 68m W (typ) 135m W (typ) 0.60 0.031 0.1µA (typ) RLOAD = 16Ω, OCL, POUT = 60m W RLOAD = 32Ω, OCL, POUT = 33m W j Shutdown Current Features n OCL or capacitively coupled outputs (patent pending) n I2C Digitally Controlled Volume Control n Available in space-saving 0.4mm lead-pitch micro SMD package n Volume control range: - 76d B to +18d B n Ultra low current shutdown mode n 2.3V - 5.5V operation n Ultra low noise Applications n n n n Mobile Phones PDAs Portable electronics devices MP3 Players Boomer ® is a registered trademark of National Semiconductor Corporation. © 2006...