LM4941_14 Datasheet, PDF (1/23 Pages) Texas Instruments – 1.25 Watt Fully Differential Audio Power Amplifier With RF Suppression and Shutdown

LM4941, LM4941SDBD, LM4941TMBD
www.ti.com
SNAS347B – JUNE 2006 – REVISED MARCH 2007
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 micro SMD 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
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.
■ Improved PSRR at 217Hz
■ Power Output, V_DD = 5.0V,
R_L = 8Ω, 1% THD+N
■ Power Output, V_DD = 3.0V,
R_L = 8Ω, 1% THD+N
■ Shutdown Current
Table 1. Key Specifications
VALUE
95
1.25
430
0.1µA (typ)
UNIT
dB (typ)
W (typ)
mW (typ)
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 © 2006–2007, Texas Instruments Incorporated