Overview
The LM49450SQ is a fully integrated audio subsystem designed for portable media player applications. This device 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 Texas Instruments’ unique 3D sound enhancement into a single device.
Key Specifications
| Parameter | Conditions | Typical | Limit |
|---|---|---|---|
| SNR at Headphone Output | - | 102 dBA | - |
| Speaker Amplifier Efficiency at 3.6V | 650mW/Channel into 8Ω | 87% | - |
| Speaker Amplifier Efficiency at 5V | 1.1W/Channel into 8Ω | 80% | - |
| Output Power/Channel Speaker at LSVDD = 5V | RL = 4Ω, THD+N ≤10% | 2.5W | - |
| Output Power/Channel Headphone at HPVDD = 2.5V | RL = 32Ω, THD+N ≤1% | 36mW | - |
| Quiescent Power Supply Current | Speaker Mode at LSVDD = 3.6V | 7.5mA | - |
| Quiescent Power Supply Current | Headphone Mode at HPVDD = 2.5V | 5.3mA | - |
| Shutdown Current | - | 0.02μA | - |
| PSRR at 1kHz | Speaker Mode | 67dB | - |
| PSRR at 1kHz | Headphone Mode | 77dB | - |
Key Features
- 24-bit I2S digital-to-analog converter (DAC)
- Stereo filterless Class D operation
- Selectable spread spectrum mode reduces EMI
- Ground-referenced headphone amplifiers with 100dB SNR
- I2S compatible audio interface supporting up to 192kHz sample rates
- 32-step digital volume control for both headphones and speaker outputs
- Texas Instruments’ 3D enhancement
- I2C-compatible control interface
- Headphone sense input for automatic detection
- Output short circuit and thermal overload protection
- Superior click and pop suppression
- Micro-power shutdown with 0.02μA current
- Available in a space-saving 32-pin WQFN package
Applications
- Portable Media Players
- Portable Navigation Devices
- Multi-Media Monitors
- Laptops
- Portable Gaming Devices
- Mobile Handsets
Q & A
- What is the primary function of the LM49450SQ?
The LM49450SQ is a fully integrated audio subsystem that combines a 24-bit DAC, Class D speaker drivers, ground-referenced headphone drivers, and other audio functionalities.
- What are the key specifications of the LM49450SQ's speaker amplifier?
The speaker amplifier delivers up to 2.5W/channel into a 4Ω load with 87% efficiency at 3.6V and up to 1.25W/channel into an 8Ω load with <1% THD+N at 5V.
- What is the SNR of the headphone output?
The signal-to-noise ratio (SNR) at the headphone output is typically 102 dBA.
- How does the LM49450SQ reduce EMI?
The LM49450SQ features a selectable spread spectrum mode to reduce electromagnetic interference (EMI).
- What is the purpose of the headphone sense input?
The headphone sense input (HPS) automatically detects the presence of a headphone and configures the device accordingly.
- What is the maximum sample rate supported by the LM49450SQ?
The LM49450SQ supports audio sample rates up to 192kHz.
- How is the volume controlled in the LM49450SQ?
The volume is controlled through a 32-step digital volume control, and it is managed via an I2C-compatible interface.
- What protection mechanisms are built into the LM49450SQ?
The device includes output short circuit protection and thermal overload protection to prevent damage during fault conditions.
- What is the shutdown current of the LM49450SQ?
The shutdown current is typically 0.02μA.
- In what package is the LM49450SQ available?
The LM49450SQ is available in a space-saving 32-pin WQFN package.
