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 8? 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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• Audio input type
• Analog Input, Digital Input
• Architecture
• Class-D
• Speaker channels (Max)
• Stereo
• Power stage supply (Max) (V)
• 5.5
• Power stage supply (Min) (V)
• 2.7
• Load (Min) (ohms)
• 4
• Output power (W)
• 1.1
• THD + N @ 1 kHz (%)
• 0.06
• Iq (Typ) (mA)
• 5.3
• Control interface
• I2C
• Closed/open loop
• Closed
• Analog supply (Min) (V)
• 2.7
• Analog supply (Max) (V)
• 5.5
• Sampling rate (Max) (kHz)
• 192
• PSRR (dB)
• 77
• Operating temperature range (C)
• -40 to 85

LM49450的完整型号有：LM49450SQ/NOPB、LM49450SQX/NOPB，以下是这些产品的关键参数及官网采购报价：

LM49450SQ/NOPB，工作温度：-40 to 85，封装：WQFN (RTV)-32，包装数量MPQ：1000个，MSL 等级/回流焊峰值温度：Level-1-260C-UNLIM，引脚镀层/焊球材料：SN，TI官网LM49450SQ/NOPB的批量USD价格：2.207（1000+）

LM49450SQX/NOPB，工作温度：-40 to 85，封装：WQFN (RTV)-32，包装数量MPQ：4500个，MSL 等级/回流焊峰值温度：Level-1-260C-UNLIM，引脚镀层/焊球材料：SN，TI官网LM49450SQX/NOPB的批量USD价格：1.839（1000+）

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