1FEATURES
2• No Output Filter Required for Inductive Loads
• Externally Configurable Gain
• Very Fast Turn On Time: 17μs (typ)
• Minimum External Components
• "Click and pop" Suppression Circuitry
• Micro-Power Shutdown Mode
• Available in Space-Saving DSBGA Package

APPLICATIONS
• Mobile Phones
• PDAs
• Portable Electronic Devices

KEY SPECIFICATIONS
• Efficiency @ 3.6V, 100mW into 8Ω Speaker:
80 % (typ)
• Efficiency @ 3.6V, 400mW into 8Ω Speaker:
88 % (typ)
• Efficiency @ 5V, 1W into 8Ω Speaker: 86 %
(typ)
• Quiescent Current, 3.6V Supply: 2.8 mA (typ)
• Total Shutdown Power Supply Current: 0.01
μA (typ)
• Single Supply Range: 2.4 to 5.5 V

DESCRIPTION
The LM4671 is a single supply, high efficiency 2.5W
switching audio amplifier. A low noise, filterless PWM
architecture eliminates the output filter, reducing
external component count, board area consumption,
system cost, and simplifying design.
The LM4671 is designed to meet the demands of
mobile phones and other portable communication
devices. Operating on a single 5V supply, it is
capable of driving a 4Ω speaker load at a continuous
average output of 2.1W with less than 1% THD+N. Its
flexible power supply requirements allow operation
from 2.4V to 5.5V.
The LM4671 has high efficiency with speaker loads
compared to a typical Class AB amplifier. With a 3V
supply driving an 8Ω speaker, the IC's efficiency for a
100mW power level is 80%, reaching 88% at 400mW output power.
The LM4671 features a low-power consumption shutdown mode. Shutdown may be enabled by
driving the Shutdown pin to a logic low (GND).
The gain of the LM4671 is externally configurable
which allows independent gain control from multiple
sources by summing the signals.