Low dropout 5v regulator (up to 800 mA)

[John Popelish]

Would anyone suggest a IC that is a 5V, low dropout voltage regulator
(regulating output from a rechargeable battery pack), up to 800 mA
current.

You'll also have to define "low". Normal follower output
regulators drop about 1.5 volts, so anything lower than that
is somebody's low drop out.

 

[John Popelish]

Would anyone suggest a IC that is a 5V, low dropout voltage regulator
(regulating output from a rechargeable battery pack), up to 800 mA
current.

Here is one that might suit you:
http://focus.ti.com/lit/ds/symlink/tps79650.pdf

 

[Ignoramus15609]

Would anyone suggest a IC that is a 5V, low dropout voltage regulator
(regulating output from a rechargeable battery pack), up to 800 mA
current.

thanks

i

 

[Martin Riddle]

LT1117
LT1118

 

[Ignoramus15609]

On first sight, looks like just what I need!

thanks!

i

 

[Winfield]

On first sight, looks like just what I need!
thanks!

An attractive feature of the tps79650 family is the noise-filter
pin in the fixed-voltage versions, which I've put to good use.

I just wish they were also available in TO-220 style packages.
It's rather hard to get much heat out of the surface-mounting
packages, even with many square inches of copper. One craves
the good old heat-sink fins.

 

[Ignoramus26085]

An attractive feature of the tps79650 family is the noise-filter
pin in the fixed-voltage versions, which I've put to good use.

Winfield, something makes me confused, they say that maximum Vin is 6
volts? (input voltage). If so, then they would not work for my 6.7v
(actual) battery pack.

I just wish they were also available in TO-220 style packages.
It's rather hard to get much heat out of the surface-mounting
packages, even with many square inches of copper. One craves
the good old heat-sink fins.

I agree, I like TO-220 myself too.

i

 

[Tam/WB2TT]

Would anyone suggest a IC that is a 5V, low dropout voltage regulator
(regulating output from a rechargeable battery pack), up to 800 mA
current.

thanks

i

LM2940 (5V version)

 

[Winfield Hill]

Winfield, something makes me confused, they say that maximum Vin
is 6 volts? (input voltage). If so, then they would not work for
my 6.7v (actual) battery pack.

Yep, those are strickly low-voltage parts - I've used them
for making 3.3V from 5V, or 1.8V from 3.3V, etc. For higher
voltages, and for +5, etc., we use parts from the Linear
Technology LT1084 and LT1085 family.

I agree, I like TO-220 myself too.

That's another reason why we use the LT1084 and LT1085 parts.

 

[Ignoramus26085]

Yep, those are strickly low-voltage parts - I've used them
for making 3.3V from 5V, or 1.8V from 3.3V, etc. For higher
voltages, and for +5, etc., we use parts from the Linear
Technology LT1084 and LT1085 family.


That's another reason why we use the LT1084 and LT1085 parts.

Win, right now in my DigiKey basket I have digikey item
LM2940CT-5.0-ND. It seems to be all I want and has very low dropout at
lower currents.

It is described here

http://www.national.com/pf/LM/LM2940.html

I think that that's what I will buy, though it only goes to 1A, but
that would be a good start for me.

i

 

[Winfield Hill]

Win, right now in my DigiKey basket I have digikey item
LM2940CT-5.0-ND. It seems to be all I want and has very low
dropout at lower currents.

It is described here http://www.national.com/pf/LM/LM2940.html

I think that that's what I will buy, though it only goes to 1A,
but that would be a good start for me.

I do use those, but I prefer the LT1084 and LT1085 because of
their higher maximum current (for a better safety margin), and
the much lower 0.75 and 0.9 C/W vs 4.0 C/W thermal resistance.
'Course at $6.50 vs $1.35, the NSC LM2940 is somewhat cheaper.

NSC does win the dropout-voltage contest, at 500mV vs 900mV at
1A load. That's because they have a high-current PNP vs LTC's
Darlington NPN pass transistor. However, LTC wins the 2.5A
dropout-voltage contest, at 1.1 to 1.2V vs awwwkk! And, LTC
wins the high-current saturated-output ground-current draw, at
an attractive 0.05mA vs an ugly 130mA. Gag me with a spoon!

 

[Ignoramus26085]

A little progress report, I soldered solid copper wires to the little
tab terminals of the battery pack, milled out the AC charger a little
bit so that the copper wires do not obstruct inserting the battery
pack, and ordered "chips". The wires are approximately 16 gauge, quite
solid.

i