LM49450 - I2C Inpt 2.5W/Ch Low EMI St Class D Sub-Sys w/ Gnd Ref Headph Amp, 3D Enhancement, & Headph Sns

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.

Products containing the "LM49450" keyword are: LM49450SQ , LM49450SQ/NOPB , LM49450SQ/NOPB , LM49450SQE/NOPB , LM49450SQEVAL , LM49450SQEVAL/NOPB , LM49450SQEVAL/NOPB , LM49450SQNOPB , LM49450SQX , LM49450SQX/NOPB , LM49450SQX/NOPB , LM49450SQXNOPB

• 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 LSV_DD = 5V:
  • R_L = 4Ω, THD+N ≤ 10%: 2.5W (typ)
  • R_L = 8Ω, THD+N ≤ 1%: 1.25W (typ)
• Headphone at HPV_DD = 2.5V:
  • R_L = 16Ω, THD+N ≤ 1%: 34mW (typ)
  • R_L = 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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