LM4920 Datasheet | National Semiconductor

Description The LM4920 is a ground referenced, fixed-gain audio power amplifier capable of delivering 80m W of continuous average power into a 16Ω single-ended load with less than 1% THD+N from a 3V power supply. The LM4920 features a new circuit technology that utilizes a charge pump to generate a negative reference voltage. This allows the outputs to be biased about ground, thereby eliminating output-coupling capacitors typically used with normal single-ended loads. Boomer audio power amplifiers were designed specifically to provide high quality output power with a minimal amount of external ponents. The LM4920 does not require output coupling capacitors or bootstrap capacitors, and therefore is ideally suited for mobile phone and other low voltage applications where minimal power consumption is a primary requirement. The LM4920 features a low-power consumption shutdown mode selectable for either channel separately. This is acplished by driving either the SD_RC (Shutdown Right Channel) or SD_LC (Shutdown Left Channel) (or both) pins with logic low, depending on which channel is desired shutdown. Additionally, the LM4920 features an internal thermal shutdown protection mechanism. The LM4920 contains advanced pop & click circuitry that eliminates noises which would otherwise occur during turn-on and turn-off transitions. The LM4920 has an internal fixed gain of 1.5V/V. Key Specifications j Improved PSRR at 217Hz j Power Output at VDD = 3V, 70d B (typ) 80m W (typ) 0.01µA (typ) 1.5V/V (typ) 1.6V to 4.2V RL = 16Ω, THD % 1% j Shutdown Current j Internal Fixed Gain j Operating Voltage Features Fixed Logic Levels Ground referenced outputs High PSRR Available in space-saving micro SMD package Ultra low current shutdown mode Improved pop & click circuitry eliminates noises during turn-on and turn-off transitions n No output coupling capacitors, snubber networks, bootstrap capacitors, or gain-setting resistors required n Shutdown either channel independently n n n n n...