LM4670 Datasheet, PDF (1/24 Pages) National Semiconductor (TI) – Filterless High Efficiency 3W Switching Audio Amplifier

LM4670
www.ti.com
SNAS240C – DECEMBER 2004 – REVISED MAY 2013
LM4670 Boomer™ Audio Power Amplifier Series Filterless High Efficiency 3W Switching
Audio Amplifier
Check for Samples: LM4670
FEATURES
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•23 No Output Filter Required for Inductive Loads
• Externally Configurable Gain
• Very Fast Turn on Time: 1.35ms (Typ)
• Minimum External Components
• "Click and Pop" Suppression Circuitry
• Micro-Power Shutdown Mode
• Short Circuit Protection
• Available in Space-Saving DSBGA and WSON
Packages
APPLICATIONS
• Mobile Phones
• PDAs
• Portable Electronic Devices
KEY SPECIFICATIONS
• Efficiency at 3.6V, 100mW into 8Ω Speaker,
77% (Typ)
• Efficiency at 3.6V, 600mW into 8Ω Speaker,
88% (Typ)
• Efficiency at 5V, 1W into 8Ω Speaker, 87%
(Typ)
• Quiescent Current, 3.6V Supply, 4.8mA (Typ)
• Total Shutdown Power Supply Current, 0.01µA
(Typ)
• Single Supply Range, 2.4 to 5.5V
DESCRIPTION
The LM4670 is a fully integrated single-supply high
efficiency switching audio amplifier. It features an
innovative modulator that eliminates the LC output
filter used with typical switching amplifiers.
Eliminating the output filter reduces external
component count, simplifies circuit design, and
reduces board area. The LM4670 processes analog
inputs with a delta-sigma modulation technique that
lowers output noise and THD when compared to
conventional pulse width modulators.
The LM4670 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 2.3W with less than 1% THD+N. Its
flexible power supply requirements allow operation
from 2.4V to 5.5V.
The LM4670 has high efficiency with speaker loads
compared to a typical Class AB amplifier. With a 3.6V
supply driving an 8Ω speaker, the IC's efficiency for a
100mW power level is 77%, reaching 88% at 600mW
output power.
The LM4670 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 LM4670 is externally configurable
which allows independent gain control from multiple
sources by summing the signals.
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Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
Boomer is a trademark of Texas Instruments.
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All other trademarks are the property of their respective owners.
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PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2004–2013, Texas Instruments Incorporated