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.