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Hot!pic16f150x Pin current

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j.p.seuret@bluewin.ch
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2020/01/15 13:13:42 (permalink)
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pic16f150x Pin current

In the datasheet of PIC16F150x I read that pin current ist 50mA. Is that correct or is that an error?
Thanks for answer, J.P.Seuret
 
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    antesther
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    Re: pic16f150x Pin current 2020/01/15 14:31:22 (permalink)
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    Pin current (source/sink) is specified in the data sheet, first page:
     
    "18 I/O Pins (1 Input-only Pin):
    - High current sink/source 25 mA/25 mA"
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    Bob White
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    Re: pic16f150x Pin current 2020/01/15 14:32:45 (permalink)
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    I am looking at the data sheet for the PIC15F1508/1509.
     
    In Table 29-4 you will see that the output high and low voltages are specified at single digit milliamps of current in order to maintain the output voltages within the appropriate logic levels.  I would not design for output source or sink currents higher than these.
     
    Looking at the specifications, with Vdd = 5.0 V the maximum output low voltage is 600 mV when sinking 8 mA.  This corresponds to an effective on-resistance of the output MOSFET of about 75 ohms.  This is a maximum value but suppose the typical was half of that.  Then the output on-resistance is about 35 ohms and trying to sink 50 mA would give you an output low voltage of 1.7-1.8 V (while dissipating almost 90 mW in that output transistor).  I would not design like that.
     
    For Vdd = 3.3 V and 1.8 V the sink current for 600 mV output low voltage is even less indicating that the output MOSFET is even less enhanced and has an even higher effective on-resistance.

    Table 29-1, which give the Absolute Maximum Ratings shows that I/O pins *must* not be operated with source or sink currents greater than 50 mA or the PIC may be damaged.  And note that the output voltage, high or low, is *not* specified with currents this high.


    post edited by Bob White - 2020/01/15 14:34:07
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    ric
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    Re: pic16f150x Pin current 2020/01/15 14:53:16 (permalink)
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    j.p.seuret@bluewin.ch
    In the datasheet of PIC16F150x I read that pin current ist 50mA.

    Where exactly did you see that?
    As antesther noted, the figure +/- 25mA is mentioned, but that is the "ABSOLUTE MAXIMUM" current limit for the pins.
    You might be able to drive an LED at close to that current (noting that "absolute maximum" means what it says. Don't go 0.1mA over it, even briefly) but you certainly won't get logic level voltages out, as Bob White has documented in detail.

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