I have a circuit that produces 4 different outputs between the range of 0-5V, coming from audio biased at 2.5V (the circuits are a high + low pass filter, positive + negative peak detector)
The micro controller I am using is an ESP32. It can only take up to 3.3V on the input (3.6 if you want to push it). Since my outputs are often greater than 3.3V, it will fry the board.
That means I needed a way to lower the voltage from 5 to 3.3. One of my ideas was to use something a logic level convertor like this:
It takes 5V and makes it 3.3V, or 3.3V -> 5V. I am already using one for the light strips connected to my ESP32. The problem is, they are using transistors, which I believe won't switch fast enough for audio. Since my output is a range (0-5V) not just a constant 5V, I don't know what the output would be if the input was something like 4.2V.
Anyway, I did some more looking around and came across the 74AHCT125 Adafruit chip. It is 3-state quad buffer/line driver. The datasheet describes it as a "a high-speed Si-gate CMOS device". It says it's 'high-speed', so I'm hoping it will work with audio.
In the datasheet under section 9 - static characteristics, it provides a good table:
I don't really understand it though. Unlike the logic level convertor, there are no low/high voltage pins, just input and output pins. If I were to put 2.0V in, how would it know whether I wanted more than 2V out or less than 2V out?
Is anyone able to provide more insight into this chip? Or even better, a way to covert a range of 0-5V to a range of 0-3.3.
The micro controller I am using is an ESP32. It can only take up to 3.3V on the input (3.6 if you want to push it). Since my outputs are often greater than 3.3V, it will fry the board.
That means I needed a way to lower the voltage from 5 to 3.3. One of my ideas was to use something a logic level convertor like this:
It takes 5V and makes it 3.3V, or 3.3V -> 5V. I am already using one for the light strips connected to my ESP32. The problem is, they are using transistors, which I believe won't switch fast enough for audio. Since my output is a range (0-5V) not just a constant 5V, I don't know what the output would be if the input was something like 4.2V.
Anyway, I did some more looking around and came across the 74AHCT125 Adafruit chip. It is 3-state quad buffer/line driver. The datasheet describes it as a "a high-speed Si-gate CMOS device". It says it's 'high-speed', so I'm hoping it will work with audio.
In the datasheet under section 9 - static characteristics, it provides a good table:
I don't really understand it though. Unlike the logic level convertor, there are no low/high voltage pins, just input and output pins. If I were to put 2.0V in, how would it know whether I wanted more than 2V out or less than 2V out?
Is anyone able to provide more insight into this chip? Or even better, a way to covert a range of 0-5V to a range of 0-3.3.