Some may have noticed that the voltage standards for microcontrollers vary; some operate at 3.3V while others use 5V. Why isn’t there a unified standard? Is this a historical legacy issue or an inevitable result of technological evolution? Today, we will explore this question.
1. The Aftermath of the TTL and CMOS ‘Cold War’
The Rise of 5V: Early digital circuits were dominated by the TTL (Transistor-Transistor Logic) standard, making 5V the de facto industrial standard.
The Breakthrough of 3.3V: The CMOS process, with its low power consumption advantages, has overtaken, but to maintain compatibility with older devices, 3.3V and 5V have been forced to coexist for a long time.
2. The ‘Impossible Triangle’ of Power Consumption and Speed
The Cost of 5V: High voltage leads to high power consumption, causing it to gradually fall out of favor with the rise of mobile devices.
The Compromise of 3.3V: Lowering the voltage can save power, but it requires sacrificing noise immunity or signal integrity.
3. The ‘Watershed’ of Process Technology
The ‘Moat’ of 5V: Fields such as automotive electronics and industrial control still require the high anti-interference capability of 5V.
The ‘Comfort Zone’ of 3.3V: Consumer electronics and IoT devices tend to favor lower voltages to extend battery life.
4. The ‘Chain Effect’ of IP Cores and Peripherals
Market Constraints: Hundreds of millions of legacy devices rely on 5V, and changing the voltage would require reconstructing the ecosystem.
The Rise of New Forces: New architectures like ARM Cortex-M and RISC-V support multiple voltages from the design stage.
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