1FEATURES

2• 16-Bit Resolution Stereo DAC

• I2S Digital Audio Data Serial Interface

• SPI Serial Interface (Control Register)

• Volume Control (32 steps; 1.5 dB Increments)

• Up to 50mW/Channel Stereo Headphone

Amplifier

• Zero Crossing Detection for Silent Attenuation

Steps

• 2.6VDC to 5.0VDC Digital Supply Voltage Range

• 2.6V DC to 5.5VDC Analog Supply Voltage Range

(See (1))

• Unity-Gain Stable Headphone Amplifiers

• Available in the 20-bump DSBGA Package

KEY SPECIFICATIONS

• PSRR at 217Hz, A/DVDD = 3V, (See Figure 1):

52dB (typ)

• POUT at AVDD = 3.0V, 32Ω

– < 0.05% THD: 13mW (typ)

– < 0.05% THD: 26mW (typ)

• Supply Voltage Range

– DVDD: 2,6V to 5.0V

– AVDD: (See (1)) 2.6V to 5.5V

• Shutdown Current: 1μA (typ)

APPLICATIONS

• Mobile Phones

• PDAs

• Portable Electronic Devices

DESCRIPTION

The LM4921 combines a 16-bit resolution stereo I2S

input digital-to-analog converter (DAC) with a stereo

headphone audio power amplifier. It is primarily

designed for demanding applications in mobile

phones and other portable communication device

applications. The LM4921 features an I2S serial

interface for the digital audio information and a 16-bit

SPI serial interface for internal register control and

communication. With AVDD and DVDD = 3.0VDC and

driving a 32Ω single-ended load to a 26mWRMS

output level the distortion (THD+N) of the LM4921 will

be less than 0.5%. The LM4921 also features a

programmable 32-step digital volume control

accessed through an SPI interface.

Boomer audio power amplifiers were designed

specifically to provide high quality output power with a

minimal amount of external components. It is,

therefore, ideally suited for mobile phone and other

low voltage applications where minimal power consumption is a primary requirement.

The LM4921 features a low-power consumption

shutdown mode, and also has an internal thermal

shutdown protection mechanism.