For all the electronics guru’s out there
Stumbled across this
Low-Dropout Linear Regulators chip of 1A rating, same footprint as the AMC7135, instead of using 350 or 350mA chips, would this 1A chip replace almost 3 of them?
As in using the NX1117C33Z or NX1117C33Z at 3.3vdc regulation 1A max thermal control, could this actually be a “high current” version of the AMC7135?
Datasheet
http://www.nxp.com/documents/data_sheet/NX1117C_NX1117CE_SER.pdf
No.
These are voltage regulators, not current regulators like 7135.
NX1117CADJZ/NX1117CEADJZ can be configured as a current regulator, but this will require additional resistor and completely new PCB (they are not pin-to-pin compatible with 7135).
And they have extremely low efficiency in this application, and cannot be controlled by PWM.
This is a voltage regulator -the AMC7135 is a current regulator. If you used the 3.3 volt version to drive an XM-L2, the current would be about 2.4A. If you put 3 of these on a driver, it would probably work, but it would drive the led at 2.4A. If you put 6 of these on a driver, it would still drive the led at 2.4A because you would still be at 3.3v.
I can’t find the original micro bridge data sheet for the 7135 and the adtek one is much abbreviated. I believe the original listed a higher current for the TO-252 package(either .7A or 1A) but I have never seen one of these chips. I could be wrong about that current rating, it might have been a wattage rating instead.
daggumit
I have one.
I guess you are talking about this:
No other differences between SOT-89 and TO-252.
That was it. Thanks Alex. Interesting to note that 700mW figure which corresponds to ~2V excess at 350mA. It went on to tabulate trace ares needed to dissipate that much wattage listing up to 1000 mm^2 for each chip at that excess. I doubt if a 105C has much more than 150 mm^2 for all 8 chips(adding up ground pads and ground rings).
It’s quite hard to get that much of excess voltage in the real flashlight (assuming it’s running on 1Li-Ion with 4.2-4.35V max).
The LED itself will need at least 2.7-2.8V, battery sags under load and pretty quickly loses voltage with discharge, then enter all the wires, springs, switches and cold contacts…
Li-ions aren’t the only cells out there. Higher voltages are still common in power tool packs and almost any Zener mod is likely to encounter a greater excess voltage than present in a single li-ion build. The biggest source of heat will still be the led but it’s important to know the whole picture to avoid mistakes.