LM4941, LM4941SDBD, LM4941TMBD

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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

1

FEATURES

•

No output coupling capacitors, snubber

networks or bootstrap capacitors required

2

•

Improved RF suppression, by up to 20dB over

previous designs in selected applications

APPLICATIONS

•

Fully differential amplification

•

Mobile phones

•

Available in space-saving micro SMD package

•

PDAs

•

Ultra low current shutdown mode

•

Portable electronic devices

•

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

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 8

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.

Table 1. Key Specifications

VALUE

UNIT

■ Improved PSRR at 217Hz

95

dB (typ)

1.25

W (typ)

430

mW (typ)

■ Shutdown Current

0.1µA (typ)

1

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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2

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PRODUCTION DATA information is current as of publication date.

Copyright © 2006–2007, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.