How does one select and recommend the right amplifier? It is not easy and requires some effort. However, with the right tools and a few straight forward questions, the engineer can narrow the recommendations to a few good selections. Renesas recommends using their offline selector tool and the following list of questions. First, one should determine the global priorities. What are the most important factors driving the purchase decision? What is the expected timing? Usually, there are one or two overriding factors that will determine the decision such as price, budget, available space, or a key performance like power or drift. Is the customer attempting to replace an existing part that works well, or is this a brand new requirement? When defining the amplifier needs, it is useful to start at the power requirements. What are the supply voltage and the supply current? At a high level, this can really narrow the potential list of amplifiers. The next step is to determine the sensor characteristics. This provides information on the level of precision needed as well as the source impedance characteristics. This will lead to the definition of the input signal. The customer will need to know if it is a current or a voltage, its amplitude and frequency, and its bias point. Is it ground sensing or high-side sensing? This will help determine what type of amplifier input stage is needed. Should it be dual supply, single supply, or rail-to-rail? The last step is to understand the output requirements. What is the needed output drive voltage and current? What are the resistive and capacitive loads? Is there any noise, THD or settling time needs? (THD is Total Harmonic Distortion) The more specific the customer can be, the better it will be to eliminate unsuitable amplifiers. The key is to learn as much about the application and amplifier needs as possible. With this information and the use of Renesas' offline selector tool (or one of the selection guides), the customer should be able to consistently get the list of recommended amplifiers down to a manageable 3-5 potential parts. At this point, there will be several parts that should work well. The decision will then be based on the relative importance of the trade-offs and the customer's priorities.