The RaspberryPi Pico series are impressive but a bit overkill as a 555 replacement 🙂
If overkill is decided by counting transistors then all microcontrollers are out, including the PICs Robert recommended earlier!
But utility, cost and convenience are far more important than transistor count. The extra functionality provided by a microcontroller becomes attractive when it costs the same as an NE555, or cheaper. And dominates if the electronics have a complex function.
The PWM board identified by Michael is as simple as it gets, so the NE555 is a good solution. But the NE555 struggles beyond that -doing more requires extra electronics, adding cost and complexity. Simple is good, too simple is bad.
Most microcontrollers have internal hardware that outputs fast, phase correct, and phase & frequency correct PWM on several pins. And programmers can write code to ‘bit bang’ PWM as well. Much easier to build a multi-motor system with a microcontroller than NE555s.
Modern electronics designs use microcontrollers galore; billions of them sold worldwide. Cheaper because they keep component counts down and improve flexibility – features can be added and changed by reprogramming rather than altering the hardware.
The Pico is interesting because its microcontroller contains two fast Cortex CPUs, with 8 PWM outputs each. If 16 PWM outputs aren’t enough, there are also 8 independent state machines that can be programmed to do PWM – at high speed.
I have huge respect for the NE555 – it’s brilliant. But time marches on, it’s not 1975! Fifty years later, microcontrollers are even more brilliant. As always the problem is keeping up. Using the NE555 is relatively simple electronics. Microcontrollers require entirely different skills, not easily acquired!
Dave