Overview
The LM49450SQX/NOPB from Texas Instruments is a highly 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. It is optimized for low power consumption, high efficiency, and minimal external components, making it ideal for space-constrained and power-sensitive applications.
Key Specifications
| Parameter | Conditions | Typical | Limit |
|---|---|---|---|
| SNR at Headphone Output | A-weighted | 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 5V | RL = 4Ω, THD+N ≤10% | 2.5W | - |
| Output Power/Channel Speaker at 5V | RL = 8Ω, THD+N ≤1% | 1.25W | - |
| Output Power/Channel Headphone at 2.5V | RL = 16Ω, THD+N ≤1% | 34mW | - |
| Output Power/Channel Headphone at 2.5V | RL = 32Ω, THD+N ≤1% | 36mW | - |
| Supply Voltage | - | - | 6.0V (max) |
| Shutdown Current | - | 0.02 μA | - |
| PSRR at 1kHz (Speaker Mode) | - | 67 dB | - |
| PSRR at 1kHz (Headphone Mode) | - | 77 dB | - |
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
- I2C-compatible control interface
- TI’s 3D enhancement for widened or narrowed soundstage
- 32-step digital volume control for both headphones and speaker outputs
- Headphone sense input for automatic detection of headphones
- Output short circuit and thermal overload protection
- Superior click and pop suppression
- Micro-power shutdown with 0.02 μA typical 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 LM49450SQX/NOPB primarily used for?
The LM49450SQX/NOPB is primarily used for portable media player applications, integrating a 24-bit DAC, Class D speaker drivers, and headphone amplifiers.
- What is the maximum output power of the speaker amplifiers at 5V?
The maximum output power of the speaker amplifiers at 5V is 2.5W per channel into a 4Ω load with THD+N ≤10%.
- What is the signal-to-noise ratio (SNR) at the headphone output?
The SNR at the headphone output is typically 102 dBA.
- Does the LM49450 support 3D audio enhancement?
Yes, the LM49450 features TI’s 3D enhancement that widens or narrows the perceived soundstage of a stereo audio signal.
- What is the shutdown current of the LM49450?
The shutdown current of the LM49450 is typically 0.02 μA.
- What type of audio interface does the LM49450 support?
The LM49450 supports an I2S compatible audio interface.
- How does the headphone sense input work?
The headphone sense input (HPS) automatically detects the presence of a headphone and configures the device accordingly.
- What kind of protection does the LM49450 offer?
The LM49450 offers output short circuit and thermal overload protection.
- What is the package type of the LM49450?
The LM49450 is available in a space-saving 32-pin WQFN package.
- What are some of the key applications for the LM49450?
The LM49450 is used in portable media players, portable navigation devices, multi-media monitors, laptops, portable gaming devices, and mobile handsets.
- How does the spread spectrum mode reduce EMI?
The spread spectrum mode reduces EMI by modulating the switching frequency, which helps in minimizing electromagnetic interference.
