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How to filter the 5V USB power supply line?
If you do need significantly more capacitance than 10µF then the FTDI application note shows one way that you can design a slow start into your circuit to limit the inrush current. I have all of those components available in through-hole form. The long leads and the breadboard interconnects are not ideal from a noise point of view.
How does a USB 2 power supply filter work?
Firstly here’s how the USB 2 supply looks with filtering: I’m sure you’ll agree that this is a huge improvement over the unfiltered supply. Noise is infrequent and limited to 50mV when it does occur. Again you can see that the filter has done its job very well with noise levels about the same as for my USB 2 port.
How to get clean 5V from noisy 5v USB power?
I need it to drive some ADC circuits that requires very clean 5v. LDO regulator need 5.2V to give 5V good power, what else can I do to otbatin good 5V from USB besides putting some 100uF tantulum cap on the supply? You can use an LC filter to filter the 5 V to the ADC reference input.
Why is my USB power supply not filtering?
The long leads and the breadboard interconnects are not ideal from a noise point of view. All those exposed wires will probably act as tiny little antenna picking up stray noise from the environment. Now let’s take a look at how the power supply line has cleaned up with the filtering components in place.
What kind of Zener is needed for 5V microcontroller?
Select a zener diode with a Vz that is higher than the Vcc powering the microcontroller, but less than the voltage that will cause damage. For 5V systems, 5.1V zeners such as the 1N5231 and the 1N4733 are commonly used. Special electronic components specifically designed for ESD protection are available.
What kind of resistor do I need for a microcontroller input circuit?
A resistor of a couple of hundred ohms and a capacitor of .01 or .1 microfarads will give reasonable protection to the input. An RC circuit is also known as a low pass filter.
What kind of input protection does a microcontroller need?
Input Protection. Goals. Integrated circuits (ICs) are made up of sensitive transistors. Most are rated for 3 to 5 Volts DC although newer ones operate at even lower voltages. Exceeding that voltage can damage or destroy the IC. Electro Static Discharges (ESD) from human contact can exceed 10,000 Volts.