Post by thread:5V low dropout regulator???

Aaron Hickman wrote: > Can anyone suggest a 5V regulator with low quiescent current and > able to supply at least 100mA of current? There are so many to choose > from, so I thought some of you might have a favorite I could start with. > Aaron, Take a look at National Semiconductor's LP2954A, it can supply up to 250mA. Dropout: 60mV (typ) at 1mA 310mV (typ) at 100mA Quiescent: 90uA (typ) at 1mA 4.5mA (typ) at 100mV The last spec may be unacceptable (we use it at a load of 500uA). They also have an output switchable model: LP2957A. --Matt

Aaron, I use LM2937 or LM2936 they both good for 125 C Andre Aaron Hickman wrote: > To all, > > Can anyone suggest a 5V regulator with low quiescent current and > able to supply at least 100mA of current? There are so many to choose > from, so I thought some of you might have a favorite I could start with. > > Sincerely, > > Aaron Hickman

In a message dated 9/30/98 7:18:31 AM Pacific Daylight Time, spam_OUThickmaabTakeThisOuTDUNX1.OCS.DREXEL.EDU writes: << To all, Can anyone suggest a 5V regulator with low quiescent current and able to supply at least 100mA of current? There are so many to choose from, so I thought some of you might have a favorite I could start with. Sincerely, Aaron Hickman >> Hi Aaron, I have used the Toko line with great success. They are available from digikey. They have a three terminal version that will do in excess of 180ma with 60ua quiescent current. Dave Duley P.S. Why does the name Aaron have two 'A's? just wondering

I've had good success with the NatSemi LM2937ET-5.0. These are good to 500mA. Aaron Hickman wrote: {Quote hidden}> > To all, > > Can anyone suggest a 5V regulator with low quiescent current and > able to supply at least 100mA of current? There are so many to choose > from, so I thought some of you might have a favorite I could start with. > > Sincerely, > > Aaron Hickman Nino. -- ****************************************************** * Antonio (Nino) Benci * * Electronic Services Manager * * Monash University - Dept of Physics * * Wellington Rd, Clayton. 3168 * * Victoria, Australia. * * TEL - 61 3 9905 3649, FAX - 61 3 9905 3637 * * EMAIL - .....nino.benciKILLspam@spam@sci.monash.edu.au (work) * * - fleatechKILLspammailexcite.com (private) * * WWW - http://www.physics.monash.edu.au/ * ******************************************************

I use the LM2936 because it also has a VERY low quiescent current. It doesn't provide 100ma - in fact I use two in parallel in one design because it was the best choice when the design was implemented several years ago. Measurement of typical quiescent currents showed them to be much better than the data books worst case. Perhaps there is now a better choice. If anyone can suggest a very low dropout very low quiescent design that also does 100ma I also would like to know. . A discrete component regulator using 4 transistors (or 3 if the main pass element is a darlington) will better any commercial design (3 years ago :-)) in terms of quiescent current, dropout and pass current but the higher parts count may make it unacceptable. . .regards Russell -----Original Message----- From: Aaron Hickman <.....hickmaabKILLspam.....DUNX1.OCS.DREXEL.EDU> > Can anyone suggest a 5V regulator with low quiescent current and >able to supply at least 100mA of current? There are so many to choose >from, so I thought some of you might have a favorite I could start with. >Aaron Hickman >

Russell, When you paralleled these, did you need any ballast resistors? What kind of pass transistor do these regs. have internally? Is it bipolar or CMOS. If bipolar, I would think that you would need the balast resistors for temperature stability (unless the reg has its own internal temp compensation which is good enough) and to handle small diferences in the gain of the transistors. Sean At 11:24 AM 10/1/98 +1200, you wrote: {Quote hidden}>I use the LM2936 because it also has a VERY low quiescent current. It >doesn't provide 100ma - in fact I use two in parallel in one design >because it was the best choice when the design was implemented >several years ago. Measurement of typical quiescent currents showed >them to be much better than the data books worst case. Perhaps there >is now a better choice. If anyone can suggest a very low dropout very >low quiescent design that also does 100ma I also would like to know. >. >A discrete component regulator using 4 transistors (or 3 if the main >pass element is a darlington) will better any commercial design (3 >years ago :-)) in terms of quiescent current, dropout and pass >current but the higher parts count may make it unacceptable. >. >.regards > > Russell > >{Original Message removed}

Hi I have used the MAX667. I needed it to generate 5v from a 9v battery source. So far I have had no hassles at all. Maxim, the manufacturers state that it can deliver 250 mA output current. The data sheet can be downloaded at: http://www.maxim-ic.com/efp/PwrSup.htm Good luck

Sean Breheny wrote: > When you paralleled these, did you need any ballast resistors? What > kind of pass transistor do these regs. have internally? Is it bipolar > or CMOS. If bipolar, I would think that you would need the ballast > resistors for temperature stability (unless the reg has its own > internal temp compensation which is good enough) and to handle small > diferences in the gain of the transistors. I don't think so. Notwithstanding the internal construction, most regulators are designed to current limit, and to taper the limit current according to temperature. As such, the regulator whose setpoint (voltage) is higher will provide as much current as it chooses, allowing the other to make up the balance. A bit crude, but much like paralleling a regulator with a resistor to "ballast" most of the current if you can predict the load, as is done in most TV sets! -- Cheers, Paul B.