Test/Review of Apple 12W USB power adapter model A1401

EDC Gear for Flashlight Carriers USB Power Devices
1

Apple 12W USB power adapter model A1401



Official specifications:

  • 12 watt USB power adapter
  • Compatible with iPad, iPhone and iPod
  • Output: DC 5.2V, 2.4A
  • Input: AC 100-240V 50/60Hz


I bought this in the Apple webshop, this way I know it is not a fake.



I got this charger in a cardboard box with a picture of the charger on the outside.



The box contained the charger, manual and warranty card.









Measurements

  • Standby power: 0.05 watt
  • Output is coded as Apple 2.4A





The charger can deliver 2.5A before it shuts down due to overload and has a very good efficiency (Very good).



No problem running at 2A for one hour.
The temperature photos below are taken between 30 minutes and 60 minutes into the 1 hour test.



M1: 48,6°C, M2: 48,1°C, HS1: 54,5°C
The hot spot here must be the rectifier diode.



M1: 47,1°C, M2: 40,0°C, HS1: 55,7°C
Here the hot spot is the trafo.



M1: 45,0°C, M2: 36,1°C, M3: 44,0°C, HS1: 50,6°C



M1: 46,6°C, M2: 52,6°C, M3: 39,3°C, HS1: 56,6°C
Here the hot spot matches the switch mode controller.



M1: 48,4°C, M2: 46,8°C, HS1: 64,1°C
And the power transistor.



There is not much noise at 0,5A with 21mV rms and 230mVpp



At 2A there is a more noise with 33mV rms and 390mVpp



Tear down



I could not break the charger open and had to cut it.



Notice the white plastic shield that goes around the usb connector to improve isolation and mechnical strength.
The metal knot to hold the plug in place is connected inside the circuit, it has 1kOhm to the usb ground.



With the shield fully in, most of the low volt section is isolated from the mains.



The yellow tape inproves the isolation between the mains input and the mains capacitors.
The plastic part is marked on the inside.



The circuit board have some white stuff on it, probably to improve isolation, it hides a bridge rectifier and two capacitors.
A switch mode controller IC and a opto feedback chip can also be seen on the circuit board.





The two blue capacitors is the safety capacitors. There is also a fuse and it is directly connected to the power input.



Without the isolation tape both inductors can be seen, both the common mode at the input and a series inductor.



The output wires from the trafo goes around the isolation barrier and to the edge of the circuit board.
Below the capacitor is a chip. The plastic stand below the capacitor must be something special made for Apple with a hole for the chip.
The rectifier diode is on the other side of the circuit board.



Without the tape the power transistor can also be seen



It is probably the opto feedback that limits the isolation distance.



Testing with 2500 volt and 5000 volt between mains and low volt side, did not show any safety problems.


Conclusion

It is no surprise that this charger can deliver the rated current with fairly low noise and is safe. I am impressed with its efficiency at higher current, it is above 80%. The actual construction looks on the expensive side, but it makes the charger very compact.

It is a very good charger, but mostly for Apple equipment due to the coding.



Notes

Index of all tested USB power supplies/chargers
Read more about how I test USB power supplies/charger
Another tear down and much more technical analysis of an iPad charger (older generation) by Ken Shirriff

2

It looks that I can continue using this for my pad without fear :slight_smile:

Thanks for a great review!

3

That is a great review dude. Are you an electrical engineer or something in real life?

4

Yes, but for some years I have mostly done programming.

5

“It is a very good charger, but mostly for Apple equipment due to the coding.”

I’m new to this sort of thing and am wondering what this means.

Can this power supply be used with something like Xtar Usb chargers.

Thanks

6

Yes, because Xtar ignores the coding and only looks for voltage drop (This is a way to see if a power supply is overloaded).

Smart phones usual look for the codes and will not charge fast if they do not recognize it.

7

Stupid phones :wink:

8

Thank you, HKJ, for all your help and the test/reviews that you have provided for the community. Your tests have to be one of the best helps and collections of knowledge that I have ever seen.

About this Apple USB power supply. It seems to me that it is a very good value even though it costs more than most of the other ones. Considering reliability, build quality and overall performance would you say that it is well worth the investment?

Again, thank you very much for being such a helpful resource for me and the community.

9

Yes, you might be able to find better chargers for less money, but it is often a gamble. With the Apple you can buy it direct from Apple and know you get the real deal.

10

As always review is chock full of solid observations and trustworthy conclusions. Like many others, I sure do look forward to these high-quality reviews.

11

This looks like the adapter that Apple issued a recall for (only some prong types): Apple Recalls "Duckhead" Power Adapters for Select Mac Laptops and iPads

The description of the problem is a bit vague. It makes me wonder whether other USB power adapters can have the same potential problem.

12

It might very well be. The recall seems to be because the mains connector part can break apart.

Other adapters may have the same problem, but it is a very difficult problem to pinpoint. The standards specify some test that it has to pass and the Apple adapter may have passed these tests as new, but the glue may have weaken over time.

Other adapters from lesser brand may get away with less mechanical strength and nobody will ever complain loudly enough about it to make the news or require a recall.

13

this is a very good overview of it was interesting
http://shop-parts.kz/product/usb-power-adapter-12w

14

What do you mean by coding? Are you saying that there is a signal sent on one or more of the USB data lines which some devices can recognise? I presume that if the data lines are dead, then by default a device simply draws current in order to charge, assuming it supports USB charging of course.

15

Exactly and different manufacturers uses different and incompatible codes. You can see more about it here: USB charging

Phones may not charger without getting a valid code or usb communication, many other devices ignores codes and usb communication and just draws power.

16

Thank you.