• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 31 subscribers
  • Views 6428 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

NE5532: Single supply operation specification

Stephen Pape
Prodigy 30 points
Part Number: NE5532


The power supply specification in the datasheet is VCC+ 22V maximum and VCC- -22V maximum. We are operating a device with VCC- = 0V and VCC+ = 24V. One op amp is a voltage follower to derive a 12V reference from a potential divider and the second op amp is used as an inverting amplifier with gain of two with the 12V reference on the inverting input. Input an output to the second op amp are ac coupled.

The reason for questioning the single supply operation is that we have damaged  three devices so far. With the ingle supply operation should VCC+ be limited to 22V ?

  • 0
    TI__Guru* 84915 points
    Hi, Stephen,

    There shouldn't be any issue regarding your power supply configuration. However, we will do some testing and let you know our findings.

    In the meantime, could you provide your circuit schematic? In addition, do you have details about the analog input signal that you are using?

    Thank you.

    Best regards,
    Luis Fernando Rodríguez S.
  • 0 in reply to Luis Fernando Rodriguez S.
    Prodigy 30 points

    Hi Luis,

    Thank you for getting back to me. We have managed to bottom out the issue - the DC blocking capacitor at the op amp input appears to be the cause of the problem. We have changed a 1uF TAJA Tantalum for a 1uF ceramic capacitor and the circuit now works fine. I do not understand why it caused the first three devices to fail. We have re-tested them and still no output with the correct input circuit. 

    If I get time I will re-test with the original circuit and see if there is an oscillation somewhere. The circuit is an audio amplifier used to boost the output of an SGTL5000 audio codec to 700mV. I will probably change the 1uF DC blocking capacitor to something more reasonable for an audio path - such as a 220uF in line with the SGTL5000 app note.

    I think this can be closed.

  • 0
    Guru 140200 points
    Hi Stephen,

    we use the NE5532 in exactly this way since decades. So, there should not be any issue.

    But we always have a resistor in series to the output of NE5532 of at least 100R. This not only to provide an isolation of capacitive loads but also to limit eventual short circuit currents. Although the NE5532 is short circuit current limited at the output, short circuiting a big AC coupling capacitance (47µF aluminium electrolytic, e.g.) at the output of NE5532, originally charged up to Vcc/2, can nevertheless destroy the NE5532! This is also valid for many other OPAmps.

    Kai