Teardown: Apple AirTag
Article By : Brian Dipert
Bluetooth-based trackers definitely aren’t a "dime a dozen," as this teardown analysis makes obvious.
Last April, they were officially introduced after a lengthy leadup of feverish industry rumors. And last November, I recommended them, along with a competitor’s conceptually similar offerings (one of which had endured my teardown attention last June), for your holiday-shopping consideration. What am I referring to? Apple’s AirTags tracking devices, of course, as anyone who paid attention to this write-up’s title has already figured out (the competitor I was alluding to is Tile, by the way).
Given that I’ve already dissected a Tile Mate, it’s only fair that I subject an AirTag to the same scrutiny, right? I thought you’d agree.
This particular unit comes from one of several four-pack sets that I recently purchased on sale:
Buh-bye, near-future victim…
What am I using the others for? One is going on each of my wife’s and my keychains, in my case supplementing (and likely eventually replacing) a Tile Mate. Tile’s recent acquisition by Life360, a company with a sketchy privacy history, has me unnerved, and I’d drop the Tile ecosystem completely if Apple were to make an AirTag derivative that fit in my wallet. Two more are going on the dogs (one each). And I’m hiding others in our various vehicles, in case they get stolen.
Here are a few close-ups of today’s patient (1.26 inches/31.9mm in diameter, 0.31 inches/8mm in height, and weighing 0.39 ounces/11 grams), as-usual accompanied by a 0.75″ (19.1 mm) diameter U.S. penny for size comparison purposes:
Unwrap the translucent protective plastic covering, pull out the lingering tab to complete the battery connection, and the AirTag plays a little tune to tell you it’s ready for you to set up (an invitation which I skipped in this instance):
Use your thumb to press down and rotate the back cover counterclockwise and it pops right off, revealing the user replaceable standard CR2032 battery inside:
Now it’s time to really get inside. Notice the seam between the white and grey portions of the chassis, in back? That’s our path to the interior. iFixit used a vise to squeeze the sides, thereby widening the gap enough to fit a plastic pick in the seam, but I went with a tongue & groove pliers (commonly also known by the Channellock brand name) and my trusty thin flat head screwdriver instead:
Voila: our first peek at the innards:
Here’s a close-up of the perspective we’re likely all most interested in:
That metal circle in the center (complete with a dab of dried glue up top, which resisted all rubbing alcohol-augmented attempts to remove it) is magnetized and combines with a coil of wire surrounding it (and the AirTag chassis more generally) to form the unit’s speaker. A piezo transducer such as that found in the Tile Mate would have been smaller, lighter and likely notably less costly, too, but apparently Apple was willing to spend (and charge us to compensate, of course) more for better audio quality. Topside glue aside, the magnetized circle fell right out of the remainder of the AirTag assembly when I turned it upside down:
Now let’s get that PCB out of the case. Lots of tenacious glue held it in place, the seam between it and the case was virtually invisible, and I had to proceed carefully to avoid shattering the PCB into multiple pieces, but I eventually succeeded (although alas, this particular AirTag is never going to play its little tune again):
The last thing to go was a tiny flex cable connecting the PCB to the dark grey assembly (plus copper speaker coil, of course) underneath. Why it exists at all will shortly become obvious:
I wasn’t able to get the dark grey piece out of the rubberized white case that surrounded it (I think I already mentioned the abundance of stubborn glue, right?), but I did succeed in snapping a bit of it off, revealing metal between it and the case. Metal? Ah, there must be a multi-antenna assembly in there , therefore the cable between it and the PCB. Per the FCC filing for ID BCGA2187, the AirTag supports both 2.4 GHz Bluetooth Low Energy (LE) and ultra-wideband (UWB) frequencies ranging from 6489.6 MHz to 7987.2 MHz, along with near-field communications (NFC):
Last, but definitely not least, let’s look more closely at the PCB itself:
The topside, which we saw before when it was still within the case, is dominated by (among other things) five 100 µF electrolytic capacitors (the packaged devices labeled “J107S”). VCC contacts for the shared battery are on both sides (upper corners, to be precise) of the GND connection. Also visible is a Bosch BMA280 (PDF) accelerometer, along with a whole mess of test points.
Now let’s flip the PCB over:
Much of the landscape here is populated by passives. That said, the largest single chunk of real estate is taken up by what I believe to be the sole proprietary IC in this design, Apple’s U1 UWB transceiver (the silver rectangular chip). Other semiconductor content here, which requires varying degrees of squinting to discern, includes:
- Nordic Semiconductor’s nRF52832 Bluetooth and NFC processor (which we’ve seen before), with accompanying 32 MHz and 32.768 kHz crystals
- A GigaDevice GD25LE32D 32 Mbit serial NOR flash memory, presumably present for code storage purposes
- Maxim Integrated’s MAX98357AEWL (PDF) class D audio amplifier
- An ON Semiconductor FPF2487 dual-channel over-voltage protection load switch, and
- From Texas Instruments, the TPS62746 DC-DC buck converter and TLV9001IDPWR single-channel op amp
So there you have it: a $29 MSRP (with free optional custom engraving, though, so there’s that!) when purchased standalone, or $99 for four, versus a bill-of-materials (plus manufacturing, test, transport, warehousing, etc.) cost that presumably still garners Apple a tidy profit. Thoughts, readers? Leave ‘em in the comments!
This article was originally published on EDN.
Brian Dipert is Editor-in-Chief of the Edge AI and Vision Alliance, and a Senior Analyst at BDTI and Editor-in-Chief of InsideDSP, the company’s online newsletter.