6th September 2007 12:26 AM
LDO replacement for 7805?
I am looking for a replacement for the crappy 7805. For my Binary clock, I am using the 780-05 (the 1.5amp), and it craps out when the voltage reaches about 7volts and I require a extremely smooth voltage because I am using the LS series. It can power my cheapo leds. I am looking for a pin compatable (same pinout) and hookup as the 7805, that has a input voltage at least 6volts. So it will start to fail me at 6 volt input. I am using rechargeable batteries, so that can be pesky. THANKS!
7805!!!!!!!!!!!!!!!! WOOT SN7400!!!!!!!!!!!!!!!!!!!!!!!!!
(just some randomness there)
6th September 2007 12:33 AM
I also would rather it be TI part. I love Texas instruments, they are nice to me. All their chips are good.
I need about 750ma or more. I also need 5 volt. THANKS
6th September 2007 12:55 AM
I was searchin around and Found a few. This one in particular. I ordered one of each one that I was interested in (3 of them) and ordered only one of them. Here is the link to the one I liked the best:
6th September 2007 01:02 AM
LM2937 from National will give 500ma at 5V.
The LM2940-50IKCSE3 from Ti will give 1A at 5V
Both are low drop out devices and are pin compatible with the 7805
6th September 2007 03:40 AM
Many low dropout regulators must have a 10uF to 100uF capacitor on their output to ground or they oscillate badly.
Some oscillate if the capacitor has a low ESR and others oscillate if the capacitor has a high ESR.
6th September 2007 10:39 AM
I stuck lots of caps on it to smooth out the voltage since I was dealing with the LS series.
6th September 2007 07:17 PM
I got my samples today (one of each, 3 total) and I am going to test them out.
7th September 2007 01:51 AM
I replaced the 7805 with the new and improved 780M05 Low Dropout regulator. I got it to put out a decent 5v output (4.98 if you want to get technical) when the voltage hit its roof, of about 6.5 volts. ME HAPPY. The binary clock will run much longer with it on there. about how many mA does a average (any/most) TTL LS series chip use? around 20 ma?
I am using 21 LEDS at 8ma
10ttl chips*n(ma use)=x
7th September 2007 04:20 AM
TTL LS uses a lot of current. You should have used Cmos because it uses almost no current.
An LED display also uses a lot of current. An LCD uses a very low current but it needs to be lighted when it is dark.
7th September 2007 03:28 PM
sorry for the offtopic but why does TI gives freely all these stuff to everyone that states that studies electronics or works for a company?!
is it really better advertasing for them?! the transportation costs must be
huge.. with FedEX and UPS...
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