Getting low power right involves a lot of different parts of a design, many of them intertwined. Usually they require the engineer to tradeoff one aspect for another. We’ve been designing low power systems for a long time, and it seems every day customers ask for better performance while keeping power at a minimum.
The low power mantra has been going on for years with no signs of stopping. A large category of devices are being built specifically because of the portability of battery systems which due to technological advances make applications practical. Fitness tracking, medical devices, and many other systems require long periods of operation without recharging. In comes the low power.
When thinking of low power, we usually tend to rush to pick a microcontroller or similar device because of its low power CPU. 150uA/MHz is in the range of many devices these days. But, have you considered that looking at the CPU is the wrong approach?
Let’s look at a typical low power data logging application. Given some sensor, we want to take samples and store them. Do we need the CPU? An ADC can work with the DMA to move the converted samples to RAM. An external Flash interface could then help move the data to an actual flash. Did we use the CPU? No. The peripherals, if they’re designed with low power in mind, can make or break an application, and you should look at them first.