Remember my April 2023 teardown of Spotify’s now-defunct Car Thing?
Ditch the touchscreen LCD, broaden functionality and that’s Amazon’s Echo Auto in a nutshell:
Shown here and introduced in mid-2019 is the first-generation version of the product, which I’ll be tearing down today. It originally sold for $49.99 but was initially promo-priced at half that amount ($24.99), which is how it came to be in my possession that same summer. The second-gen successor, introduced three years (and three months) later with shipments beginning in mid-December 2022, was smaller, with beefier mounting options, equivalent claimed input-sound quality (in spite of fewer integrated mics) and a supposed superior sonic output, along with a permanent 24.99 price cut. It’s still available for purchase:
Considering that the first-gen Echo Auto has been sitting on my shelf for more than 5 years now awaiting my dissection attention, the beat-up condition of its packaging, as-usual accompanied by a 0.75″ (19.1 mm) diameter U.S. penny for size comparison purposes, would be understandable…except that it’s looked like this since it first showed up at my front door!
Rip off the retaining tape and flip open the top flap:
and the contents come into view.
Post-removal, here’s our patient, alongside the similarly clear plastic-clad (at least for the moment) dashboard mount:
the “cigarette lighter” 12V socket-based power supply, flanked by (on the left) a 3.5mm TRS extension cable and (on the right) the USB-A to micro-USB power cable, all three of which I’ll hold on to for future reuse:
and, of course, a few slivers of documentation:
Next, a couple of additional looks at the adhesive dash mount (and its accompanying preparatory dashboard-cleaning handi wipe), now free of its clear plastic sarcophagus:
and the power adapter, with a handy included second USB-A jack, and decent aggregate output:
With the contents removed and its insides now ostensibly empty, the box still seems hefty, but I confirmed that there was nothing left within. Must be all those folded cardboard layers:
And now for some initial perspectives on our patient, with dimensions of 3.3” x 1.9” x 0.5” (85 mm x 47 mm x 13.28 mm) and a weight of 1.6 oz (45 grams). Front:
The left “mute” button, by the way, turns red when active, as with other Echo devices, as does the more general multicolor device-status light bar along the bottom edge:
The device top is comparatively bland, although there is that inside access-tempting seam:
The sides are more interesting. Along the right are the 3.5mm auxiliary analog audio output and the micro-USB power connector. The former was a key motivation for me to initially buy the Echo Auto, as none of my vehicles have integrated Bluetooth, far from Apple’s CarPlay or Google’s Android Auto services—only my wife’s newer car does—but their sound systems all have AUX inputs.
And on the left? No, that’s not a SD card slot. Believe it or not, it’s the aperture for the integrated speaker, pointing toward the vehicle’s driver (at least sometimes):
Finally, the device backside, revealing (among other things) the FCC ID (2ALV8-4833) and magnetic dash mount inset (I trust there’s metal inside, on the other side of the chassis):
Speaking of “inside”, let’s get to it. A preparatory peek underneath one of the rubber feet seemingly wasn’t promising:
So, I turned my attention to the aforementioned top side seam. The first “spudger” I tried slipped inside fairly easily but was too flimsy to make any separation headway:
Its beefier Jimmy sibling, however, was no more successful:
On a hunch, I revisited those feet. That grey piece of plastic you saw underneath the one in the earlier photo? Turns out, it pops out too:
And underneath each of the plastic pieces is a hex screw head begging for attention:
That’s more like it:
FWIW, as it turns out from my subsequent research, I wasn’t the only one initially flummoxed!
There’s that piece of metal I’d previously forecasted would be on the other side of the dashboard mount inset. Below it, along the bottom edge, is a portion of the light guide assembly (presumably associated with a to-be-seen row of LEDs on the PCB):
And here’s our first glimpse of the system’s guts:
On the left (right when viewed from the front; remember that we’ve so far removed the back panel) is the micro-USB power input, with the 3.5 mm audio jack above it. Along the bottom are—I told you so—a row of 11 multicolor LEDs. At the top is the PCB-embedded Bluetooth antenna. And on the right? That, believe it or not, is the mono speaker! Let’s get it outta there:
Lest there be any doubt as to its magnet-inclusive acoustic identity:
And now for some closeups, with perspectives oriented per the transducer as originally installed in the previous photo. Right side, where the sound comes out; I seriously doubt it “goes to 11”:
Front:
Left side:
Back, exposing the speaker’s electrical contacts:
And finally, the top:
and bottom:
With the speaker removed, you can now see the PCB-resident “spring” contacts that mate up with those on the speaker. Note, too, that the PCB holes corresponding to mounting pins on the speaker backside are foam-reinforced, presumably to suppress vibration while in operation:
And now let’s get the PCB out of there, a thankfully easier process than what’d previously been necessary to get our first glimpse of it, as it now lifts right out of the remaining chassis half:
The stuck-on RFID tag inside the front chassis half is an interesting story in and of itself. As this blogger also postulates (in addition to identifying the source—Inpinj—of the IC connected to the comparatively massive antenna), I believe that it finds use in uniquely associating the device with your Amazon account prior to its shipment to you. To wit, I happened to notice, in reviewing my Amazon order history to refresh my memory of when I bought the Echo Auto and what I paid for it, that the device serial number was also included in the relevant transaction listing. And at the bottom is the other portion of the light guide assembly:
Here’s the already-seen PCB backside, now free of its previous plastic chassis surroundings:
And here’s the first-time glimpsed PCB front side:
Let’s first get rid of that rubber gasket, which thankfully peeled off easily:
Note the LEDs straddling the left-side switch, which generate the red “mute” indication. Note, too, eight total circular apertures for the microphone array, one in each corner of each of the two switches. And as for the ICs between the switches, let’s zoom in:
Unfortunately, I had no luck in identifying any of these; I’m once again hopeful that insightful readers can fill in the missing pieces. The one at the bottom (U10), when correctly oriented (it’s upside-down marked in the photo) has what looks to be an “OXZ” company logo stamped in the upper left corner. The three-line product marking next to it looks like this:
L16A
0225
ZSD838A
I found similar markings (albeit with second-line deviations) on an IC inside a 2018-2019 13” Apple MacBook Air, within a Facebook post which I stumbled across thanks to Google Image Search, but that’s all I’ve got. Above it are two ICs (U2 and U6) identically marked as follows:
YE08
89T
which may be 8-bit bidirectional voltage-level translators, specifically Texas Instruments’ TXB0108. And in U10’s upper right corner is another (U9) with the following two-line marking:
T3182
3236A
Again…
Let’s flip the PCB back over to its backside and see if we have any better luck. Step one is to get those two Faraday Cages’ tops off:
That’s better:
The IC at far left (U20), next to a wire-wound inductor whose guts seem to have been inadvertently exposed by the spudger while removing the cage, is labeled thusly (and faintly so):
25940A
TI 89I
AE24
“TI” stands for “Texas Instruments”, I’m pretty confident, reflective of the longstanding partnership between that supplier and Amazon also noted in several of my past Echo product dissections. And Texas Instruments does have a “25940” in its product line, specifically the TPS25940, the “eFuse Power Switch”, a “compact, feature-rich power management device with a full suite of protection functions, including low power DevSleep support”. If that’s actually what this chip is, its proximity to the micro-USB power input therefore makes sense. But the product page also claims that the TPS25940 is intended for use in SSDs. Hmm…
Above and to the right of it is another chip with “TI” in the markings (U14), but the first line thankfully makes its function more obvious, at least as far as I’m guessing:
DAC
3203I
TI 88J
PL49
This, I believe, is Texas Instruments’ TLV320DAC3203 “stereo” audio DAC with a stereo 125-mW headphone driver and audio processing. Proximity is again part of the probable identity tip-off here, since it’s near the analog audio output. Plus, of course, there’s the first-line “DAC” mark…
Move further to the right and the next large(r) IC you encounter (U19), also seemingly chipped in one corner during my clumsy cages-removal surgery, has the following two-line primary markings (along with, above them, a combo mysterious swirl followed by a seeming QR code):
W902B108
SR3F2
Google searches on the markings proved fruitless but, based on some other research I’ve done on this system, I’m still going to take a guess. The Amazon product page indicates that in addition to the main system SoC (hold that thought), there’s also an “Intel Dual DSP with Inference Engine” inside. The relevant DeviWiki product page further clarifies that it’s an “Intel Quark S1000 Processor.” Indulge me in a brief history diversion: a bit more than a decade ago, Intel announced its Quark line of defeatured 32-bit x86 processors (even more so than its Atom CPUs) for wearables and other cost- and power-sensitive applications. The Quark family, which Intel obsoleted in 2019, also included at least one coprocessor, the S1000, which embedded two Cadence Tensilica LX6 DSP cores. Intended for speech recognition, I assume that the S1000 also handled echo cancellation, background noise suppression and other array mic functions in this particular design. And I’m also guessing that, although there’s no Intel logo mark, it’s this chip.
Now for the main system SoC (U23), which is to the right of the previous “mystery chip” and is thankfully more easily identifiable. It’s MediaTek’s MT7697, introduced in 2016 and described as a “highly integrated 1T1R 2.4GHz Wi-Fi/Bluetooth 4.2 application processor with an Arm Cortex-M4 and a power management unit”, MediaTek being another supplier with a longstanding Amazon relationship.
Which leads us to the last chip I’ll showcase, to its right, with a two-IC PCB identifier (U17/U18). At first, I thought the “MT” mark might also indicate MediaTek sourcing but, given that the MT7697 already also handles Bluetooth and power management functions, I couldn’t think of anything else this one could tackle. But then I remembered I hadn’t yet mentioned memory, either volatile or nonvolatile. This insight led me to suspect that “MT” probably instead stands for “Micron Technology” and that this is a stacked module containing both DRAM and flash memory (capacities and specific technology types and generations unknown).
In closing, I’ll (re)point out two other aspects of this side of the PCB; the eight MEMS microphones whose apertures you saw earlier on the other side, and the PCB-embedded top-edge Bluetooth antenna that I first noted when the PCB was still chassis-bound. And with that, having just passed through 2,000 words, I’ll wrap up with a reiteration of the invitation to assist me with any/all of the ICs I was unable to ID, and/or to share any other insights or other thoughts, in the comments. Thanks as always in advance!
—Brian Dipert is the 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.
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