LM4941 Datasheet, PDF (1/21 Pages) National Semiconductor (TI) – 1.25 Watt Fully Differential Audio Power Amplifier With RF Suppression and Shutdown

LM4941, LM4941SDBD, LM4941TMBD
www.ti.com
SNAS347C – JUNE 2006 – REVISED MAY 2013
LM4941
1.25 Watt Fully Differential Audio Power Amplifier
With RF Suppression and Shutdown
Check for Samples: LM4941, LM4941SDBD, LM4941TMBD
FEATURES
1
•2 Improved RF Suppression, By Up to 20dB
Over Previous Designs in Selected
Applications
• Fully Differential Amplification
• Available in Space-Saving DSBGA Package
• Ultra Low Current Shutdown Mode
• Can Drive Capacitive Loads up to 100pF
• Improved Pop & Click Circuitry Eliminates
Noises During Turn-On and Turn-Off
Transitions
• 2.4 - 5.5V Operation
• No Output Coupling Capacitors, Snubber
Networks or Bootstrap Capacitors Required
APPLICATIONS
• Mobile Phones
• PDAs
• Portable Electronic Devices
KEY SPECIFICATIONS
• Improved PSRR at 217Hz 95dB (typ)
• Power Output, V_DD = 5.0V, R_L = 8Ω, 1% THD+N
1.25W (typ)
• Power Output, V_DD = 3.0V, R_L = 8Ω, 1% THD+N
430mW (typ)
• Shutdown Current 0.1µA (typ)
DESCRIPTION
The LM4941 is a fully differential audio power
amplifier primarily designed for demanding
applications in mobile phones and other portable
communication device applications. It is capable of
delivering 1.25 watts of continuous average power to
a 8Ω load with less than 1% distortion (THD+N) from
a 5V_DC power supply. The LM4941 does not require
output coupling capacitors or bootstrap capacitors,
and therefore is ideally suited for mobile phone and
other small form factor applications where minimal
PCB space is a primary requirement.
The LM4941 also features proprietary internal
circuitry that suppresses the coupling of RF signals
into the chip. This is important because certain types
of RF signals (such as GSM) can couple into audio
amplifiers in such a way that part of the signal is
heard through the speaker. The RF suppression
circuitry in the LM4941 makes it well-suited for
portable applications in which strong RF signals
generated by an antenna from or a cellular phone or
other portable electronic device may couple audibly
into the amplifier.
Other features include a low-power consumption
shutdown mode, internal thermal shutdown
protection, and advanced pop & click circuitry.
1
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.
All trademarks are the property of their respective owners.
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 © 2006–2013, Texas Instruments Incorporated