Why are there so few microcontrollers with integrated 16-bit ADC?

bigbat

Why are there so few microcontrollers with integrated 16-bit ADC? [Copy link]

Most of the microcontrollers we see above have 12-bit ADCs. Why are there so few microcontrollers with integrated 16-bit ADCs? Do 16-bit ADCs have special requirements in some aspects?

Gen_X

The main issue is the consistency and stability of the peripheral circuit. Generally, it is difficult to design a circuit that can meet the requirements of 12-bit acquisition.

Except for analytical purposes, most industries only need to meet the 0.1% FS requirement.

Therefore, the built-in AD is between 8 and 12 bits.

dcexpert

There is also the issue of cost.

damiaa

ADI has many ADI chips of this type

MSP430 has MSP430F42 series

There are many STM32 models.

. . . Many families

There are also many domestic

Huaxin Micro has SWM181 series

Actually, there are many. You will find them if you look for them.

Not all chips require this. Some products don't even need ADC, so having more bits is probably a waste.

If you really want to use a 16-bit ADC, the requirements are high, ADI's TI's are pretty good...

It can also be achieved with a cheap CPU + 16-bit ADC chip, which is also pretty good.

damiaa

For example, using a STC89SXX + ADS1110 (ADI's 16-bit ADC) costs 4 yuan + 6 yuan. It only costs 10 yuan.

Or you can use AT32F421 + ADS1110 (ADI's 16-bit ADC) which is about the same price.

wsmysyn

1. Design cost. If IP integration is used, the IP cost is not low. Whether it is suitable for the MCU is a problem. In addition, whether it is self-developed or using IP, high-precision ADC has certain challenges in hybrid chip design, such as noise, because they are all on a die, and the die is very small, which is much more complicated than a single ADC/DAC die.

2. Test cost. As far as I know, a 24-bit AVI64 board from ADVANTEST costs more than 100,000 US dollars. If you use special ADC test equipment with ATE, the cost is the same. For example, NI's test box is more expensive than the board.

Of course, there are special needs, which require such a high number of digits. Cost is not a problem, the price is just high.

bigbat

Thank you, I just want to know the reason. It is not necessary to use 16-bit ADC, my products also have 12-bit built-in ADC

cruelfox

I wonder if you have ever seen the distribution of the values converted by a 12-bit ADC when it samples a stable DC voltage.

To use an inappropriate analogy, the tape measure used in clothing stores only has scales of centimeters or half a centimeter. You might say that the resolution is not high enough, so why not print millimeter scales or even half a millimeter scales? In fact, even if it is printed, the measurement accuracy cannot be achieved.

boutd

Gen_X Published on 2021-9-17 09:44 It is mainly about the consistency and stability of the peripheral circuit. Generally, it is difficult to design a circuit that can meet 12-bit acquisition. In addition to analytical purposes, most of the industry...

The main issue is the consistency and stability of the peripheral circuit. Generally, it is difficult to design a circuit that can meet the requirements of 12-bit acquisition. Except for analytical purposes, most industries only need to meet the 0.1% FS requirement. Therefore, the built-in AD is between 8 and 12 bits. --- + Cost issue Good