ATmega8A - driving mosfet from output

[konradIC13]

Hello,

Will output of ATmega8A be able to drive BUZ10 Mosfet directly from its output? I want that mosfet to be driven by ATmega and switch on other device (500mA 5VDC fan).

Also would it be possible to use firstly a bc548 transistor to amplify the output signal from ATmega and then drive on the 'normal' IRF510 MOSFET ?

 

[ronsimpson]

"logic level" MOSFETs will work with low voltage inputs from digital (5V or 3.3V)

 

[konradIC13]

Yeah, i know about IRF3711 its one of the very few available for me but its relatively expensive. Thats why im looking for cheaper replacement.

 

[ronsimpson]

IRF3711=20V 92A monster big.

20V 2A :
DMN2230U-7, RTF020P02TL, NX2301P,215, AO3423,

 

[konradIC13]

I have found IRL530N N MOSFET. It has 0.150Ω Rds(on) at 4V and 0.120Ω Rds(on) at 5V. Is the Rds(on) low enough? Its also from IRF HEXFET family.

Here is datasheet https://www.electro-tech-online.com/custompdfs/2012/06/irl530n.pdf

And thank you for your suggestions ronsimpson, those MOSFETS looks nice but unfortunatly they are all not avaliable for me and international shipping is too expensive (especially when i make my project just for fun so i try to not make my wallet dry )

Also i found those:
IRLB8743PBF 4.2mΩ
IRLB8748PBF 6.4mΩ
IRLZ44ZPBF 22mΩ
IRLB8743PBF 22mΩ
irlz34npbf 60mΩ

Also what is the maximum/'dangerous' value of Rds(on) at 5v where MOSFET would work bad when driven from ATmega output and i should look for MOSFETS with Rds(on) at 5v below that value?

 

[kubeek]

Atmega doesn´t care about the Rds of the mosfet. The only thing in the relationship between atmega and mosfet that matters is the threshold voltage.
Rds affects the dissipation in the mosfet at full load, which for 500mA load current and 0.12ohm Rds is 0.03W, which is absolutely negligible. Even tiny sot-23 mosfets would handle such load with ease.

 

[konradIC13]

OK, i think i found ultimate MOSFET, its STP75N3LLH6 do you think it will work? Driven directly from ATmega output (5v max 20mA) and drain current will be 500mA
Here is datasheet of it https://www.electro-tech-online.com/custompdfs/2012/06/CD00240517.pdf
It has treshold voltage 1 to 2.5V and Rds on

 

[پروژه های الکترو]

OK, i think i found ultimate MOSFET, its STP75N3LLH6 do you think it will work? Driven directly from ATmega output (5v max 20mA) and drain current will be 500mA
Here is datasheet of it https://www.electro-tech-online.com/custompdfs/2012/06/CD00240517.pdf[size=-10]پروژه الکترونیک سیستم مانیتورینگ اتوماسیون صنعتی میکروکنترلر AVR ARM LPC STM32 PIC dsPIC[/size]
It has treshold voltage 1 to 2.5V and Rds on

What is the speed of switching frequency of MOSFET?

MOSFET's gate capacitor needs some time to get charged/discharged and depend on the pull-up/down resistor of its gate it may be greater than period of switching pulse.

So if you need a high speed switch, drive your MOSFET with some BJTs.

 

[electronicsbasecom]

What is the speed of switching frequency of MOSFET?

MOSFET's gate capacitor needs some time to get charged/discharged and depend on the pull-up/down resistor of its gate it may be greater than period of switching pulse.

So if you need a high speed switch, drive your MOSFET with some BJTs.

Also remeber to put high resistor (about 100k) between gate and souce of MOSFET, that will help for faster turning-of of MOSFET...