5/19/16: Fundamentals of Operational Amplifiers

What are the best ADI op amps for battery powered devices?

  • One might expect the answer to be the opamps that support the lowest supply voltages and lowest supply currents, but that would not always be the case.  If a signal chain requires multiple opamp stages, reducing the number of stages even if doing so requires a higher power opamp can still realize a net savings. 

    Keep in mind that power dissipation not only occurs inside the opamp, but also in the load and possibly in the feedback network.

    Duty cycling the power to the opamp or duty cycling the opamps enable pin (if available) can enable a substantial power savings without sacrificing performance in systems that are only active periodically.  In sampled data acquisition systems, a technique called dynamic power scaling can be used to realize power savings that scale with the sampling rate of the system.