1FEATURES
2• Output Short Circuit Protection
• Stereo Class D Operation
• No Output Filter Required
• Logic Selectable Gain
• Independent Shutdown Control
• Minimum External Components
• Click and Pop Suppression
• Micro-Power Shutdown
• Available in Space-Saving 2mm x 2mm x
0.6mm DSBGA Package

APPLICATIONS
• Mobile Phones
• PDAs
• Laptops

KEY SPECIFICATIONS
• Efficiency at 3.6V, 100mW into 8Ω 80% (typ)
• Efficiency at 3.6V, 500mW into 8Ω 85% (typ)
• Efficiency at 5V, 1W into 8Ω 85% (typ)
• Quiescent Power Supply Current at 3.6V
Supply 4mA
• Power Output at VDD = 5V, RL = 4Ω, THD ≤ 10%
2.5W (typ)
• Power Output at VDD = 5V, RL = 8Ω, THD ≤ 10%
1.5W (typ)
• Shutdown Current 0.1μA (typ)

DESCRIPTION
The LM4674A is a single supply, high efficiency,
2.5W/channel, filterless switching audio amplifier. A
low noise PWM architecture eliminates the output
filter, reducing external component count, board area
consumption, system cost, and simplifying design.
The LM4674A is designed to meet the demands of
mobile phones and other portable communication
devices. Operating from a single 5V supply, the
device is capable of delivering 2.5W/channel of
continuous output power to a 4Ω load with less than
10% THD+N. Flexible power supply requirements
allow operation from 2.4V to 5.5V.
The LM4674A features high efficiency compared to
conventional Class AB amplifiers. When driving an
8Ω speaker from a 3.6V supply, the device features
85% efficiency at PO = 500mW. Four gain options are
pin selectable through the GAIN0 and GAIN1 pins.
Output short circuit protection prevents the device
from being damaged during fault conditions. Superior
click and pop suppression eliminates audible
transients on power-up/down and during shutdown.
Independent left/right shutdown controls maximizes
power savings in mixed mono/stereo applications.