Drive Current Sufficiency


Closed Thread
Results 1 to 9 of 9

Hybrid View

  1. #1
    Join Date
    Oct 2005
    Location
    Sweden
    Posts
    3,610


    Did you find this post helpful? Yes | No

    Default Re: Drive Current Sufficiency

    I think perhaps we've both misinterpreted the datasheet a little bit.
    Look at table 6.5 in this Texas Instruments datasheet. There we can see that indeed the maximum input current is 1.35mA at 3.85V but a little bit further down we can see that an input current of 250uA will still produce a collector current of 100mA while only dropping a maximum of 1.1V.

    Input current on CMOS series logic chips seems to be in the uA range so no problems there.

  2. #2
    Join Date
    Dec 2012
    Location
    Türkiye
    Posts
    103


    Did you find this post helpful? Yes | No

    Default Re: Drive Current Sufficiency

    Don't you think the current at 3.85 V proportionally should increase at 5V drive voltage..? Secondly do you have any idea with my other question ?
    • Also do you think this MCU's weak current supplying ports can handle and succesfully drive the A/B/C/INH signal inputs of CD4051 and A/B/C/D/INH signal inputs of 4514 ?


    - Ipsa scientia potestas est -

  3. #3
    Join Date
    Oct 2005
    Location
    Sweden
    Posts
    3,610


    Did you find this post helpful? Yes | No

    Default Re: Drive Current Sufficiency

    Don't you think the current at 3.85 V proportionally should increase at 5V drive voltage..? Secondly do you have any idea with my other question ?
    It might, if it was allowed to but it can't since the output can only source 2mA. If you're worried, why not measure it? Add an external series resistor if you want to be sure that the circuit can't ever pull more 2mA.

    Secondly do you have any idea with my other question ?
    Please read my previous reply:
    Input current on CMOS series logic chips seems to be in the uA range so no problems there.

Similar Threads

  1. Replies: 23
    Last Post: - 25th June 2011, 23:27
  2. Can I drive a 5v LED without a current resistor?
    By Fredrick in forum Schematics
    Replies: 31
    Last Post: - 11th September 2009, 14:42
  3. Differential Drive Programming
    By shaiqbashir in forum mel PIC BASIC Pro
    Replies: 14
    Last Post: - 30th December 2006, 14:03
  4. drive relay?
    By serdar_ozcan in forum mel PIC BASIC Pro
    Replies: 1
    Last Post: - 26th November 2005, 11:01

Members who have read this thread : 0

You do not have permission to view the list of names.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts