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LM4562 getting very warm at idle

ENRICO BORSETTI
Prodigy 20 points
Other Parts Discussed in Thread: LM4562

Dear Sirs at TI,

I've made a prototype RIAA Phono pre amplifier with LM4562. The unit is fed by regulated power supply using 7815 and 7915 IC's. To avoid oscillations during testing, the input has been shorted to Gnd. Each rail is consuming 10mA at 15Vcc.

I am surprised that the case of the IC is very warm to the touch, it reached 45°C (circa 113°F). Is this the actual temperature of the 4562 when powered on?

 

I look forward to hear from you soon.

Kindest Regards,

Enrico Borsetti

 


  • 0
    TI__Guru** 111585 points
    Hi Enrico,

    Welcome to e2e.
    Have you tried to to set the input in a different condition other than connected to GND to see if there is any change?
    Why is C14 connected between pin 8 and pin 4?

    Best regards,
    -Ivan Salazar
    Texas Instruments
  • 0 in reply to Ivan Salazar
    Prodigy 20 points

    Hi Ivan,

    yes, either shorting the input to Gnd or connecting a phono cartridge or if you leave the input open, no matter what, the 4562 reaches 45°C when powered on.

    You asked about C14: this bypass capacitor is connected to the +Vcc and Vcc- rails for better noise filtering, as recommended by Ron Mancini in his great book on Op Amps.

    Thank you very much for your prompt reply.

    Looking forward to hear from you.

    Regards,

    Enrico