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Topic: Anyone know a strong P channel MOSFET (about 40v, 1A, logic level) ? (Read 5580 times) previous topic - next topic


Minimal Load:

See Page 14 of data sheet:

The maximum output current per channel is programmed by a single resistor, R(IREF), which is placed between
IREF pin and GND pin. The voltage on IREF is set by an internal band gap V(IREF) with a typical value of
1.24V. The maximum channel current is equivalent to the current flowing through R(IREF) multiplied by a factor of
31.5. The maximum output current per channel can be calculated by Equation 6:
Imax = V(iref)/R(iref) x 3.15

V(IREF) = 1.24 V
R(IREF) = User-selected external resistor.
Imax must be set between 5 mA and 120 mA. The output current may be unstable if Imax is set lower than 5 mA.
Output currents lower than 5 mA can be achieved by setting Imax to 5 mA or higher and then using dot
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.


If you are choosing a MOSFET by drain-current parameter you are probably going about things
the wrong way.

No-one would normally take a MOSFET near its max rated current value - it will need LARGE heatsink
and will dump tonnes of power.

Use the Rds(on) figure to decide if a device is suitable - you can calculate the power dissipation and
voltage drop directly from that - make sure both are sensible.  Also remember power goes as the
square of current so that 10A is four times worse than 5A for the same device - this really can bite
the unwary.  Do the maths to avoid surprises.
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