1FEATURES

2• Differential Mono Input and Stereo Single-

Ended Input

• Separate Earpiece (Receiver) Differential Input

• Analog Switch for a Separate Earpiece Path

• 32-Step Digital Volume Control (-80 to +18dB)

• Three Independent Volume Channels (Left,

Right, Mono)

• Separate Headphone Volume Control

• Flexible Output for Speaker and Headphone

Output

• True Ground Headphone Amplifier Eliminates

Large DC Blocking Capacitors Reducing PCB

Space and Cost

• Hardware Reset Function

• RF Immunity Topology

• “Click and Pop” Suppression Circuitry

• Thermal Shutdown Protection

• Micro-Power Shutdown

• I2C Control Interface

• Available in Space-Saving DSBGA Package

KEY SPECIFICATIONS

• Supply Voltage (V DDLS): 2.7V ≤ VDDLS ≤ 5.5V

• Supply Voltage (VDDHP): 1.8V ≤ VDDHP ≤ 2.9V

• I2C Supply Voltage: 1.7V ≤ I2CV DD ≤ 5.5V

• Output Power, VDDLS = 5V, VDDHP = 2.75V, 1%

THD+N

– RL = 8Ω Speaker 1.3W (Typ)

– RL = 32Ω Headphone 45mW (Typ)

• Output Power VDDLS = 3.3V, VDDHP = 2.75V,

1% THD+N

– RL = 8Ω Speaker 540W (Typ)

– RL = 32Ω Headphone 40mW (Typ)

• PSRR: VDD = 3.3V, 217Hz Ripple, Mono In:

90dB (Typ)

• Shutdown Power Supply Current: 0.01μA (Typ)

APPLICATIONS

• Portable Electronic Devices

• Mobile Phones

• PDAs

DESCRIPTION

The LM49101 is a fully integrated audio subsystem

with a mono power amplifier capable of delivering

540mW of continuous average power into an 8Ω BTL

speaker load with 1% THD+N using a 3.3V supply.

The LM49101 includes a separate stereo headphone

amplifier that can deliver 44mW per channel into 32Ω

loads using a 2.75V supply.

The LM49101 has four input channels. A pair of

single-ended inputs and a fully differential input

channel with volume control and amplification stages.

Additionally, a bypass differential input is available

that connects directly to the mono speaker outputs

through an analog switch without any amplification or

volume control stages. The LM49101 features a

32–step digital volume control on the input stage and

an 8–step digital volume control on the headphone

output stage.

The digital volume control and output modes,

programmed through a two-wire I2C compatible

interface, allows flexibility in routing and mixing audio

channels.

The LM49101 is designed for cellular phones, PDAs,

and other portable handheld applications. The high

level of integration minimizes external components.

The True Ground headphone amplifier eliminates the

physically large DC blocking output capacitors

reducing required board space and reducing cost.