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Need Class AB recommendation with following requirements

David Blankfield
Prodigy 280 points
Other Parts Discussed in Thread: LM4951A

Need help on recommendation for portable audio amp application.

Class A/B is preferred over class D.

 Below are the requirements for the Audio PA received.

  • 1.8W @ 16ohm speaker load  

  • Vcc : At least 6V to 10V. (Preferable 5V to 12V).

  • Amplifier should accept Analog input

  • Amplifier should provide Differential output : 1.8W minimum @ 16W.  (Preferable :  2W @ 16W speaker).

  • Low distortion : <10% @ max power as above (max volume)

  • Low power consumption, low standby drain

  • Turn on time : 30ms minimum. (Preferable < 20ms).

  • Programmable gain : 30dB (Preferable : Gain resistor value change)

  • Preferable : 2 channel in 1 package, with individual turn on/off and mute/unmute control

  • Pop noise elimination

  • Low capacitance requirement for supply lines.

I have concluded the LM4951A is best fit for above except it is spec for 8ohm speaker vs 16ohm

Please confirm or provide alternative device that fits these requirements best.

regards,
David Blankfield TI

  • 0
    TI__Guru** 109395 points
    Hi David,

    According to the application requirements LM4951A seems a good fit.
    16-Ohm speaker seems a relatively high impedance for that output power, these loads are usually used in headphone systems that require lower power. However, you can have an idea of the output power at 16-Ohm load of LM4951A from figure 33 on page 11 from the datasheet.

    Best regards,
    -Ivan Salazar
    Texas Instruments