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???
03/16/09 14:39
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 		 #163493 - serial low-side drivers
Responding to: ???'s previous message
Bing Logarth said:
hi, do you know any ic that combines uln2803 and a shift register like 4094?

Which characteristics of the ULN2803A is that you wish to exploit?

and also, is it possible to turn on/off uln2803 by changing the value of the com pin from 1(+5v) to 0(0v)?

If you look at the illustrations in the datasheet that show how the transistors in the device are connected to GND and, through those free wheeling diodes to "COM" you'll see that putting GND on that COM output simply connects the outputs to GND through the diodes, which would not be a good thing. If you wish to control the ON/OFF state of the drivers with GND, you can do that, but your circuit driving GND must be capable of sinking whatever current flows in all 8 darlingtons. Is that what you want?

Maybe one of these will help you.

http://focus.ti.com/lit/ds/symlink/tpic2603.pdf
http://www.nxp.com/acrobat_d...1010_1.pdf
http://www.elmos.de/uploads/t...910_02.pdf

RE


List of 55 messages in thread
TopicAuthorDate
ULN2803 with shift register            01/01/70 00:00      
   TPIC            01/01/70 00:00      
   serial low-side drivers            01/01/70 00:00      
      Turning off ULN2803 Output            01/01/70 00:00      
         IOL for one pin is commonly 10mA            01/01/70 00:00      
            Blue Smoke?            01/01/70 00:00      
               no. No, NO            01/01/70 00:00      
               accidental double, ignore            01/01/70 00:00      
            10 mA??? I don't think so!            01/01/70 00:00      
               I quoted 10mA for the 8051            01/01/70 00:00      
                  My aplogies ...            01/01/70 00:00      
         Sorry, Bing, but what you plan is nonsense!            01/01/70 00:00      
   In a FAQ I started            01/01/70 00:00      
   how much current, which voltage, for what            01/01/70 00:00      
   TPIC6B595            01/01/70 00:00      
      It is not available here in India            01/01/70 00:00      
         I'm confused...            01/01/70 00:00      
         What would happen if ...            01/01/70 00:00      
            Or Maybe I make my own IC            01/01/70 00:00      
               before you make your own IC            01/01/70 00:00      
                  Semicon plants and School Labs have foundries            01/01/70 00:00      
                     For one chip ?            01/01/70 00:00      
                        It is a special kind of service they offer for students            01/01/70 00:00      
                     Go ahead ... Give them a try!            01/01/70 00:00      
                     Sorry, but I doubt this...            01/01/70 00:00      
                        asked, at least 3 times            01/01/70 00:00      
                           I have not measured it yet            01/01/70 00:00      
                              SInce that's the most important bit of information ...            01/01/70 00:00      
                                 I am on vacation            01/01/70 00:00      
                              ridiculous            01/01/70 00:00      
                                 Even more simple            01/01/70 00:00      
                                    about 100 micro amps            01/01/70 00:00      
                                       the why on earth do you use a power chip?            01/01/70 00:00      
                                       Then you don't need the 2803 at all!            01/01/70 00:00      
                                          74hc595?            01/01/70 00:00      
                                             Why not look at a datasheet?            01/01/70 00:00      
                                             NOW, that you FINALLY answer the question            01/01/70 00:00      
                                                I still am considering making my own IC            01/01/70 00:00      
                                                   before you do so            01/01/70 00:00      
                                                   You are severely deluded            01/01/70 00:00      
                                                      r u envious?            01/01/70 00:00      
                                                         evidence            01/01/70 00:00      
                                       RE: about 100 micro amps            01/01/70 00:00      
                                          Spooky glow            01/01/70 00:00      
                                       Cutting Vegetable Using Sword...!!!...???            01/01/70 00:00      
                                          Nice Metaphors            01/01/70 00:00      
                                             my favourite            01/01/70 00:00      
                                                my favourite-            01/01/70 00:00      
                                          in light of the original poster's other threads ...            01/01/70 00:00      
               Bing, what current has to flow?            01/01/70 00:00      
               You might have a bit of trouble with that.            01/01/70 00:00      
                  Similar to            01/01/70 00:00      
                     Allegro            01/01/70 00:00      
                        That part is pretty expensive in small lots.            01/01/70 00:00      
   IO expansion            01/01/70 00:00      

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