LM4665 Datasheet, PDF (1/28 Pages) National Semiconductor (TI) – Filterless High Efficiency 1W Switching Audio Amplifier

LM4665
www.ti.com
SNAS146E – FEBRUARY 2002 – REVISED MAY 2013
LM4665
Filterless High Efficiency 1W Switching Audio
Amplifier
Check for Samples: LM4665
FEATURES
1
•2 No Output Filter Required for Inductive
Transducers
• Selectable Gain of 6dB (2V/V) or 12dB (4V/V)
• Very Fast Turn On Time: 5ms (typ)
• User Selectable Shutdown High or Low Logic
Level
• Minimum External Components
• "Click and Pop" Suppression Circuitry
• Micro-Power Shutdown Mode
• Short Circuit Protection
• DSBGA, WSON, and VSSOP Packages (No
Heat Sink Required)
APPLICATIONS
• Mobile Phones
• PDAs
• Portable Electronic Devices
KEY SPECIFICATIONS
• Efficiency at 100mW into 8Ω Transducer
75%(typ)
• Efficiency at 400mW into 8Ω Transducer
80%(typ)
• Total Quiescent Power Supply Current (3V)
3mA(typ)
• Total Shutdown Power Supply Current (3V)
0.01µA(typ)
• Single Supply Range (VSSOP & WSON) 2.7V to
5.5V
• Single Supply Range (DSBGA) (Note 11) 2.7V
to 3.8V
DESCRIPTION
The LM4665 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 parts count,
simplifies circuit design, and reduces board area. The
LM4665 processes analog inputs with a delta-sigma
modulation technique that lowers output noise and
THD when compared to conventional pulse width
modulators.
The LM4665 is designed to meet the demands of
mobile phones and other portable communication
devices. Operating on a single 3V supply, it is
capable of driving 8Ω transducer loads at a
continuous average output of 400mW with less than
2%THD+N.
The LM4665 has high efficiency with an 8Ω
transducer load compared to a typical Class AB
amplifier. With a 3V supply, the IC's efficiency for a
100mW power level is 75%, reaching 80% at 400mW
output power.
The LM4665 features a low-power consumption
shutdown mode. Shutdown may be enabled by either
a logic high or low depending on the mode selection.
Connecting the Shutdown Mode pin to either V_DD
(high) or GND (low) enables the Shutdown pin to be
driven in a likewise manner to activate shutdown.
The LM4665 has fixed selectable gain of either 6dB
or 12dB. The LM4665 has short circuit protection
against a short from the outputs to V_DD, GND or
across the outputs.
1
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2
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 © 2002–2013, Texas Instruments Incorporated