●The LM49450 is a fully integrated audio subsystem designed for portable media player applications. The LM49450 combines a 24-bit I2S digital-to-analog converter (DAC), 2.5W/channel stereo Class D speaker drivers, 36mW stereo ground referenced headphone drivers, volume control, and TI’s unique 3D sound enhancement into a single device.
●The filterless Class D amplifiers deliver 1.25W/channel into an 8Ω load with <1% THD+N with a 5V supply. The LM49450 offers two logic selectable modulation schemes, fixed frequency mode, and an EMI reducing spread spectrum mode. The 36mW/channel headphone drivers feature TI’s ground referenced architecture that creates a ground-referenced output from a single supply, eliminating the need for bulky and expensive DC-blocking capacitors, saving space and minimizing system cost. A headphone sense input (HPS) automatically detects the presence of a headphone, and configures the device accordingly.
●The LM49450 stereo, 24-bit DAC supports a wide range of sample rates (including 192kHz, 96kHz, 48kHz, and 44.1kHz). The digital audio signal path features better than 100dB SNR, and low 0.05% THD+N when measured at the headphone outputs. The flexible 3-wire I2S interface supports left or right justified audio data.
●The LM49450 features separate 32-step volume control for the headphones and speaker outputs. 3D enhancement, mode selection, shutdown control, and volume are controlled through an I2C compatible interface.
●Output short circuit and thermal overload protection prevent the device from being damaged during fault conditions. Superior click and pop suppression eliminates audible transients on power-up/down and during shutdown. The LM49450 is available in a space saving 32-pin WQFN package.
● 24–Bit Stereo DAC
● Stereo Filterless Class D Operation
● Selectable Spread Spectrum Mode Reduces EMI
● Ground Referenced Headphone Amplifiers with 100dB SNR
● I2S Compatible Audio Interface
● Audio Sample Rates up to 192kHz
● TI’s 3D Enhancement
● 32-Step Digital Volume Control
● I2C-Compatible Control Interface
● Headphone Sense Input
● Stereo Analog Line Inputs
● Output Short Circuit Protection
● Thermal Overload Protection
● Minimum External Components
● Click and Pop Suppression
● Micro-Power Shutdown
● Available in Space-Saving 32-Pin WQFN Package
●## Key Specifications
● SNR at Headphone Output: 102dBA (typ)
● Speaker Amplifier Efficiency at 3.6V, 650mW/Channel into 8Ω: 87% (typ)
● Speaker Amplifier Efficiency at 5V, 1.1W/Channel into 8Ω: 80% (typ)
● Quiescent Power Supply Current Line Inputs:
● Speaker Mode at LSVDD = 3.6V: 7.5mA (typ)
● Headphone Mode at HPVDD = 2.5V: 5.3mA (typ)
● Output Power/Channel Speaker at LSVDD = 5V:
● RL = 4Ω, THD+N ≤ 10%: 2.5W (typ)
● RL = 8Ω, THD+N ≤ 1%: 1.25W (typ)
● Headphone at HPVDD = 2.5V:
● RL = 16Ω, THD+N ≤ 1%: 34mW (typ)
● RL = 32Ω, THD+N ≤ 1%: 36mW (typ)
● PSRR at 1kHz
● Speaker Mode: 67dB ( typ)
● Headphone Mode: 77dB (typ)
● Shutdown current: 0.02μA (typ)
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