AD8618 supply decoupling

Hello,

I'm designing a PCB with four AD8618, single supply +3V and all channels as voltage followers (see attached figure, U3-U6). U1 is the voltage regulator in the circuit, and the output is decoupled with a 4.7uF tantalum cap (C2). Now my question is whether I actually need the decoupling caps on the op-amps (C5-C12). I'm using two decoupling caps per op-amp, one 0.1uF ceramic and one 10uF tantalum. The PCB traces between U1 and U4 (as well as U1 and U5) is approx. 4 cm. The traces between U1 and U3 (as well as U6) is approx. 10 cm.

If you please have some ideas on this I would be very grateful!

Thanks in advance,

Elias

InterfacePCB.pdf
Parents
  • Harry,

    Many thanks for your reply. At the moment we plan to build 4 of these boards. We might order one first and test the overshoot and oscillatory behaviour as you suggest. In any case, how could this behaviour be lessened?

    Regarding the GBP, should the overshoot be larger when the desired bandwidth is much smaller than the GBP? i.e. if I use the AD8618 I should expect more oscillations than if I use the AD8604?

    /Elias

Reply
  • Harry,

    Many thanks for your reply. At the moment we plan to build 4 of these boards. We might order one first and test the overshoot and oscillatory behaviour as you suggest. In any case, how could this behaviour be lessened?

    Regarding the GBP, should the overshoot be larger when the desired bandwidth is much smaller than the GBP? i.e. if I use the AD8618 I should expect more oscillations than if I use the AD8604?

    /Elias

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