National Semiconductor LM4921 Low Voltage I2S 16-Bit Stereo DAC with Stereo Headphone Power Amplifiers and Volume Control
Summary
The LM4921 is a highly integrated, 16-bit stereo Digital-to-Analog Converter (DAC) designed for portable electronics. This component combines low-voltage digital audio conversion with internal stereo headphone power amplifiers and programmable volume control, allowing for minimal external components. The manual provides comprehensive technical details, including electrical specifications, I²S interface usage, pin configurations, and operating parameters. It is ideally suited for manufacturers creating demanding mobile phones, PDAs, and other low-power communication devices requiring high audio quality.
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LM4921 Low Voltage I2S 16-Bit Stereo DAC with Stereo Headphone Power Amplifiers and Volume Control General Description Key Specifications The LM4921 combines 16-bit resolution stereo I2S input
PSRR at 217Hz, A/DVDD 3V, (Fig. 1) 52d B (typ)
digital-to-analog converter (DAC) with stereo headphone
POUT at AVDD 3.0V, 32Ω
audio power amplifier. It is primarily designed for demanding
applications in mobile phones and other portable communi- 0.05% THD 13m W (typ)
cation device applications. The LM4921 features an I2S
0.5% THD 26m W (typ)
serial interface for the digital audio information and 16-bit
Supply voltage range
SPI serial interface for internal register control and commu-
nication. With AVDD and DVDD 3.0VDC and driving 32Ω DVDD 2.6V to 5.0V
single-ended load to 26m WRMS output level the distortion AVDD (Note 8) 2.6V to 5.5V
(THD+N) of the LM4921 will be less than 0.5%. The LM4921
Shutdown current 1µA (typ)
also features programmable 32-step digital volume control accessed through an SPI interface. Boomer audio power amplifiers were designed specifically to Features provide high quality output power with minimal amount of
16-bit resolution stereo DAC
external components. It is, therefore, ideally suited for mo-
I2S digital audio data serial interface
bile phone and other low voltage applications where minimal
SPI serial interface (control register)
power consumption is primary requirement.
Volume Control (32 steps; 1.5 d B increments)
The LM4921 features low-power consumption shutdown
Up to 50m W/channel stereo headphone amplifier
mode, and also has an internal thermal shutdown protection
Zero Crossing Detection for Silent Attenuation Steps
mechanism.
2.6VDC to 5.0VDC digital supply voltage range 2.6VDC to 5.5VDC analog supply voltage range (Note 8) Unity-gain stable headphone amplifiers Available in the 20-bump micro SMD package
Applications Mobile phones PDAs Portable electronic devices
Boomer® is registered trademark of National Semiconductor Corporation.
National Semiconductor Corporation DS200486 www.national.com
Page Summary Contents For National Semiconductor LM4921 Low Voltage I2S 16-Bit Stereo DAC with Stereo Headphone Power Amplifiers and Volume Control
Manual Details
| Brand | National |
|---|---|
| Pages | 18 |
| File Size | 467.02 KB |
| Published | June 15, 2026 |
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Frequently Asked Questions
What is the DAC resolution and input type?
It features a 16-bit resolution with stereo I²S input for digital audio information.
How many steps are available for volume adjustment?
The programmable digital volume control offers 32 steps, with increments of 1.5 dB.
What is the typical low-power shutdown current?
The device has a typical shutdown current of 1µA.
What operating temperature range does this DAC support?
It supports an operating temperature range from -40˚C to 85˚C.