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OPA564-Q1: Power Sequence

Shota Mago
Expert 6580 points
Part Number: OPA564-Q1

Hi team,

My customer considers employing OPA564-Q1 and provided a question in terms of power sequence.

He would like to use OPA564-Q1 with ±12V supply.

Datasheet describes "Sequencing of power supplies must assure that the digital supply voltage be applied before the supply voltage to prevent damage to the OPA564-Q1." and Figure.36 shows power supply sequencing.

Considering above condition, is below power sequence correct?

V-(-12V)→VIDG(-8V)→V+(12V)  

If you have other recommended sequence example or reference circuit, it should be helpful.

I look forward to hearing back from you.

Best regards,

Shota Mago

  • 0
    TI__Guru* 93105 points

    Hello Shota,

    The OPA564-Q1 required power supply sequence involves bringing VDIGITAL up before, or in unison with VSUPPLY as illustrated in datasheet Fig. 36.

    The easiest way I have found to satisfy this requirement is to power VDIGITAL directly from VSUPPLY using a resistive voltage divider. You can see how this can be accomplished for an OPA564-Q1 dual supply circuit in this TINA circuit diagram:

    There is a natural tendency to connect a capacitor from the Vdig pin to ground for additional filtering. However, don't because it will slow the rise of VDIGITAL relative to VSUPPLY and can ruin the supply sequence. Alternately, a series resistor with a 4.7 or 5.1 V zener diode can be used to bias VDIGITAL.

    If a single supply arrangement is being used to power the OPA564-Q1, the voltage divider can be powered off the V+ supply.

    Regards, Thomas

    Precision Amplifiers Applications Engineering