Need a low power mosfet

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1

Hello everyone,
I need a cheap mosfet to power my little vibrator like that in a mobile phone. I will be using a I2C 8 channel buffer to control the mosfet. These are the details of the vibrator:

DC 3-5V Voltage
Usage Range: 2.5-4V
DC Rated Current : 70mA
Max Start Current: 901mA Max

For now I need through hole package but will need SMD later.

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Hi Jason,

Just a couple questions, what microcontroller are you using? How do you intend on using the I2C buffer?

We have some transistors that may be up to spec here.

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Hi Jason
Jack’s questions are very valid.

You have to accommodate this, irrespective of your operating current.
Just had a look at a couple on the Core shop.
The IRLZ34N would probably do. The graphs indicate it is switched on at 3.3V (in case you are using this logic level) a bit more than the others. SKU COM-24144.
Of course if you are using 5V logic all the better. These things like to be switched pretty much hard ON. Stay cooler that way.
Don’t forget about 1kΩ resistor in series with the gate to limit the gate capacitor charge current to a safe value.
Cheers Bob

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I am using the Arduino Nano Every with the TCA9548 I2C 8 channel buffer board. It supports voltages between 1.8V, 2.5V, 3.3V and 5V buses Level shifting
Also, my project runs on battery so it needs to be low power.

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Hi Jason
A “low power” Mosfet is not going to change your current requirement. I think your motor will be a fair contributor, particularly if you have a lot of stops and starts at nearly 1A per time.
Cheers Bob

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Hi Jason

I think you are making a mistake in trying to fit a project into a particular battery size.
Get your project working.
Trim it down to get rid of excess.
Work out how much power you actually need.
Add some for a “Fudge factor”. I usually go to nearly double. Don’t have any power problems that way.
THEN size the battery you will need.
Cheers Bob

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Minimum times 2 is how I’ve learnt to spec batteries. When there is additional things you forgot you wanted to add you won’t be in as much trouble.

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I’ve decided to use a powerful (10A 5V) DC power supply and see what my project draws. Then decide on the battery situation . Also going to use the IRLZ34N. Thanks everyone :slight_smile:

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Hi Jason

A very wise move. You should have no power problems. That Power supply will then be useful for the same situations or for something like LED XMAS lights etc.

That should be OK.
Cheers Bob

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