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Why is there no ULN 2003 replacement !?

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GrandAlf

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Anyone know of a drop in replacement, that has active low inputs. Or is it just one of those things that would be really useful, but is not actually made. It would just save a board re-design if such thing were available. Googling produced nothing useful. I am always surprised that certain components are just not made. Example as above, would be great for MCUs that usually have high outputs during the reset period. Better than having to use inverters. Another one, why no common anode bi colour leds. Would make sense, as most logic can sink more that it can source. Better still, 2 leds in one package (4 wires), either way round. I can think of others, so sensible, but not seemingly made!
 

Use MC1413.
 

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Thanks for the info, much appreciated. However these appear to be identical to ULN2003 rather than active low inputs.
 

The ULN2003 and the MC1413 have active low outputs, they are open-collector so they can't be anything else!

Are you looking for an equivalent with active low INPUTS ? something like the 2003 but non-inverting.

Brian.
 

i think no such circuit exist with active low inputs and compatible pin to pin with ULN2003. all most IC that i find on the web are active high inputs. some exception with 2/8 port ACTIVE LOW INPUT (74ACT8244).
 
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Sorry I did not make it clearer, yes of course active low Inputs. Not really a problem about pin compatability, just function. Would save board space rather than have to use inverters for every input. Will check out 8244, thanks.
 

I think the problem is that it's difficult to make an active low input without a source of power to turn the device off when the input is high or open circuit. The ULN20xx series are basically darlington arrays so they need base current to turn them on, working the other way around would require a current source to turn them off and there isn't one available without increasing the package size.

I did some research and there are quite a few devices that have active low inputs though, for example Sanyo make the LB1249 and Hitachi make the HA13408 which is a 9 channel driver. They are marketed as motor drivers rather than general purpose but they do the same thing.

Brian.
 

Thats useful info, many thanks Brian. I would have thought that it would not be too difficult incorporate inverters with weak pulldown on the darlington. It always seems a little odd that devices like this are not more common. Since most micros have their ports go high during reset, they are going turn everything connected on for several milliseconds, this may not be desirable. There are ways round this of course, but generally easier to use active low if possible. Of course you would need a current souce, do not need to be pin compatible with anything though, I was just considering new designs.

Mike
 

No, that's not what was asked for. The BA12001 - BA12004 are equivalents to the ULN2001 - ULN2004. What GrandAlf is looking for is a NON-inverting version, one where the output is conducting when the input is low.

Brian.
 

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M63800FP
Click to expand...

This looks like a source driver instead of a sink. So not really like the ULN2...
 

use 2N3904 with 10K resistor in series

---------- Post added at 09:43 ---------- Previous post was at 09:41 ----------

you could use the UDN2981A from Allegro Microsystems or one of the TD62783 series chips from Toshiba. These are both 8-channel open-collector drivers in 18-pin packages, near enough identical in rating and operation to the ULN2803
 

No !

Still not what is wanted. The query is for an open collector current sink with the same capability of a ULN2003 but one that is turned ON (sinking current) when the input is LOW instead of when the input is high. In other words functioning like a ULN2003 fed from an inverter.

Brian.
 

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