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rprodrigues
Joined: 18 Nov 2006
Posts: 53
Helped: 1
Location: Itajubá MG Brazil
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 04 Nov 2009 15:07 Looking for a 5v to 3.3V, 500mA regulator high efficiency |
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Hi all,
I would like to receive your suggestions for and simple 5v to 3.3V regulator with output of 500mA, high efficiency and within DIP or TO packages.
DC-DC converters with inductors are not welcome. 
I found MAX604, but I think it is too expensive (about $ 4 per unit).
Any suggestions?
Thank you,
RPR
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FvM
Joined: 22 Jan 2008
Posts: 5160
Helped: 767
Location: Bochum, Germany
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04 Nov 2009 15:35 Looking for a 5v to 3.3V, 500mA regulator high efficiency |
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You're on a wrong track.
All linear regulators have basically the same efficiency (except for small differences caused by the quiescent current). It's about 65 % in your case.
Only regulators utilizing an energy storage can achieve a higher efficiency. These are first of all your unwanted inductive buck converters. In principle, also a fractional switched capacitor circuit can convert 5 to 3.3V, but it's somewhat complex, and as far as I know, not available for 500 mA current level. National LM3351 is working up to 50 mA. So you are stuck with inductive converters or poor efficiency.
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mandar_mahajan
Joined: 08 Jul 2009
Posts: 97
Helped: 1
Location: mumbai
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05 Nov 2009 5:02 Re: Looking for a 5v to 3.3V, 500mA regulator high efficienc |
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LM117 & LM317 are 5v to 3.3v converters.
Search their datasheets to find package no. which will meet ur spects.
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FvM
Joined: 22 Jan 2008
Posts: 5160
Helped: 767
Location: Bochum, Germany
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05 Nov 2009 8:19 Looking for a 5v to 3.3V, 500mA regulator high efficiency |
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By specification, standard regulators as LM117 can't guarantee the required low dropout voltage. A low-dropout type
as LM1117 is required for 5 to 3.3V. Personally, I would prefer a today's type, that doesn't bring up stability issues with
low-ESR output capacitors.
As already mentioned, the efficiency can't be higher than 65%, so if low power is an objective, a switching regulator
should be considered.
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rprodrigues
Joined: 18 Nov 2006
Posts: 53
Helped: 1
Location: Itajubá MG Brazil
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06 Nov 2009 16:27 Looking for a 5v to 3.3V, 500mA regulator high efficiency |
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Thank you guys.
I'm going to use a switching regulator so I can reach a efficiency higher than 65%!
Thank you.
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satishkumar
Joined: 02 Apr 2006
Posts: 73
Helped: 2
Location: bangalore
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13 Nov 2009 9:48 Looking for a 5v to 3.3V, 500mA regulator high efficiency |
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Dear All,
what is the basic difference between Switching regulators and switching controllers?
DC/DC CONV.
thanks in advance!
rgds
sh
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FvM
Joined: 22 Jan 2008
Posts: 5160
Helped: 767
Location: Bochum, Germany
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13 Nov 2009 10:03 Looking for a 5v to 3.3V, 500mA regulator high efficiency |
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| In common usage of terms, a switching regulator is a switching controller with an integrated switch.
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rprodrigues
Joined: 18 Nov 2006
Posts: 53
Helped: 1
Location: Itajubá MG Brazil
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16 Nov 2009 18:55 Re: Looking for a 5v to 3.3V, 500mA regulator high efficienc |
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| satishkumar wrote: |
Dear All,
what is the basic difference between Switching regulators and switching controllers?
DC/DC CONV.
thanks in advance!
rgds
sh |
By the way, the family LM2675 is a great family for this kind of regulators! Try them!
Added after 14 seconds:
| satishkumar wrote: |
Dear All,
what is the basic difference between Switching regulators and switching controllers?
DC/DC CONV.
thanks in advance!
rgds
sh |
By the way, the family LM2675 is a great family for this kind of regulators! Try them!
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hameeds01
Joined: 23 Aug 2005
Posts: 308
Helped: 15
Location: NUST Islamabad
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16 Nov 2009 20:11 Re: Looking for a 5v to 3.3V, 500mA regulator high efficienc |
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try this one LM3940
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