By Benson Leung
on 2015-10-29 UPDATED: TechMatte USB Type-C to MicroUSB adapter fixed with proper 56kΩ resistor! Fully recommend!
TechMatte has been extremely responsive to my inquiry in the last month. They've contacted me and let me know that they were in the process of fixing their cables. They were also kind enough to send me an early engineering sample of the fixed cables one week ago.
This re-review of their Micro-B to C adapter is not of the engineering sample, but of the real production version that I purchased again from fan-key three days ago.
Let's get started on the spec compliance test. Once again, my test device is a Chromebook Pixel 2015. I am using a Chromium Twinkie USB PD sniffer/debug device, available here : Plugable USB 3.1 Type-C (USB-C) Power Delivery Sniffer
I have plugged in the TechMatte adapter to a USB Type-A to Micro-B cable that came with my Motorola Nexus 6 phone. It is plugged into the following 10W charger : Dell 10W Adapter Spare Wall Charger for Venue 8 Pro/8/7 (XDN34)
The charger, the cable, and the adapter are plugged into Twinkie, which is acting as a passthrough to Pixel. Picture attached.
Let's run the ectool command from Pixel:
localhost ~ # ectool --name=cros_pd usbpdpower
Port 0: SNK Charger DCP 4656mV / 1872mA, max 5000mV / 1872mA / 9360mW
Port 1: SRC
So far so good. Pixel is charging at almost 1.9A from the 2A Dell charger. It's correctly identifying as a DCP charger.
Let's check Twinkie:
CC1_PD = 417
CC2_PD = 15
The ADC command reads the current voltage values from the CC pins. As you can see here, CC1_PD pin has a value of 417mV. Referring to the USB Type-C Specification Table 4-25 Voltage on Sink CC pins, this voltage falls right in the middle of the range allowed for vRd-USB, meaning that yes, this cable has the correct 56kΩ pullup resistor!
Other subjective consideration : The adapter is nice and small, perfect for slapping on your most used USB micro-b cables. It's tiny, barely wider than the Type-C plug or Type-B receptacle. Very compact design.
In conclusion : The TechMatte adapter has been updated to fully support Chromebook Pixel and other Type-C devices that depend on correct CC termination! It is now officially futureproof for the Type-C generation and gets my full recommendation. I recommend this for anyone with a USB Type-C phone like Nexus 6P/5X or Pixel device.
TechMatte as a company has been very responsive and they've gone to great lengths to follow my advice at every stage. Thank you, TechMatte!
ORIGINAL REVIEW (10/29/2015):
I'm a Software Engineer on the Chrome OS team at Google on the Chromebook Pixel and Pixel C teams.
I bought these two USB-C to Micro USB adapters from TechMatte and found they do not work properly with the Chromebook Pixel.
Upon closer inspection by our engineering team here, we have determined that this adapter is not correctly following the USB Type C specification.
The specification can be found here :
Specifically, these adapters do not charge the Chromebook Pixel 2015 because the adapters leave the C-C lines floating, where the specification requires a Rp pullup to Vbus to identify the cable as a legacy adapter or cable.
Please see the document named "USB Type-C Specification Release 1.1.pdf"
section 126.96.36.199.4 for a description of why the Rp pullup is necessary.
Please also see Section 4.11 and the following note :
1. For Rp when implemented in the USB Type-C plug on a USB Type-C to USB 3.1 Standard-A Cable
Assembly, a USB Type-C to USB 2.0 Standard-A Cable Assembly, a USB Type-C to USB 2.0 Micro-B
Receptacle Adapter Assembly or a USB Type-C captive cable connected to a USB host, a value of 56 k'
± 5% shall be used, in order to provide tolerance to IR drop on V BUS and GND in the cable assembly.
In other words, since you are creating a USB Type-C plug to a USB 2.0 Micro-B receptacle assembly, you must use a resistor of value 56k' as a pullup to Vbus. This cable does not do this.
Please let me know if there is any more information I can provide about why these adapters are problematic.
If you are a consumer looking for a cable that is compatible with Pixel, do not use this one.
5 Stars By Greg Retkowski on 2016-10-02
Compact and performs well
These are great for converting micro-usb to usb-C. I have a Nexus with the new style plug, and these adapters let me charge my phone anywhere where there's a micro plug. They are very compact, so you can carry it anywhere. I usually keep one in my wallet so it's available any time. I think I've bought six of these so far - I do misplace them every so often.
5 Stars By MomNMore on 2016-09-23
Save yourself a bundle
Huge money saver right here! For $13 I got 4 of these and stuck them on all of our car chargers and brought one to work with 'cause who doesn't have a dozen micro-USBs lying around? They work flawlessly. Since the newer smartphones hold a charge for so long and come with a high-speed cord, I hardly ever need this, but it works like a charm on my Motorola and Anker car chargers and I don;t really care if they're fast, just functional.
5 Stars By C Daniel on 2016-10-01
Revive those old micro-USB cables.
These are PERFECT. They have a nice grip to hold onto even old and worn micro USB cables and keep me from having to swap or buy all new cables for every location in which I use my phone. I keep one in my car, and one in my EDC pouch for when I don't have an actual or spare USB-C cable lying around.
5 Stars By DM on 2015-11-03
Nexus 5X Charging and Data Transfers work with no issues (both items tested)
The Nexus 5X does not come with a USB A to USB C cable for data transfers and, if you're like most smartphone shoppers, you don't already have one. I upgraded from a phone that used Micro USB cables, so I have a ton of those around the house, along with a micro USB car charger.
What these adapters do is enable you to use your hoards of Micro USB cables for your new USB C phone - probably a cheaper proposition than replacing all of your existing chargers/cables all at once.
I have tested both items that came (in the 2 pack) and both work for charging and data transfers.
Charging is notably slower than it is on the charger that the 5X came with, but that's not because of the adapters - it's because of my old chargers.
Other pros to this product are:
- They are cheap
- The connection is very tight on the micro USB side and mostly tight on the phone side
- The housing is small, so my case does not interfere with insertion
- You still get to keep your Micro USB cables/charger at hand in case you or your guests have Micro USB devices to charge, as well
Overall, so far, I see no down sides. Eventually I may upgrade to all fast chargers and new USB C 3.1 cables, but for right now this product allows me to salvage most of my investment in older Micro USB chargers.
5 Stars By Ryan on 2016-09-30
Buy these now before your battery dies!
These things are perfect. Well built also. I Originally ordered 6 of them and just bought more. I gave some to my girlfriend who also has a USB-C Android phone. She keeps one in her purse and it has saved her several times.
5 Stars By Steven S Hooper on 2016-09-23
Great item, prefect fit.
Save a ton of money, not have to change all my micro USB cords, these work great for my new charger cords.
3 Stars By AKO California on 2016-04-06
Starting to be little loose after several months
I have many micro usb cables and chargers from my old phones and devices, including some extra long cables. So I was a bit annoyed that my Nexus 5X has a USB-C connector until I saw these adapters. I've bought a regular USB-C cable for places like the car where I don't want a tiny adapter that could get lost, but I didn't want buy all new cables for the other adapters. They originally fit nice and tight on both ends and are tinier than I expected. However over time the end that goes into the phone has gotten looser. So some movement of the phone will cause it to come slightly unplugged and it'll stop charging. The white pair I have hasn't shown this problem, but this black pair has a less noticeable click when connected.
They work fine for data transfer and charging as long as I take care not to pull it out a bit. Easy to do during they day, but doesn't work for charging overnight since if I check the time, it'll often pull out a tiny bit. So I had to go to a USB C cable for that use.
One thing I don't like about them is they end up being fairly long on the end of a cable. That worries me because it is much easier to put a lot of stress on the phone socket with the adapter plus existing end on the cable. Although the stock USB C cables have longer ends than USB micro cables to begin, so this isn't that much longer. But the extra length still worries me.
5 Stars By Nathan & Andrea on 2016-10-15
Very reliable. Contact TechMatte for a free replacement in the unlikely event of a dud
The adapters arrived on time and work as advertised.
The black plastic shell on one of the adapters slid off while trying to pull it out of a cell phone. I tried putting the plastic shell back on, but I seem to have put it back on backward and now I cannot remove the shell to try again. The male USB-C port is covered by the shell, so this adapter is unusable.
The other adapter is fine and was all I needed. It is my fault for putting the shell back the wrong direction, so I will not return the product.
TechMatte contacted me and is sending me a replacement product for free. I will consider them first when buying similar products.
I use one of the adapters daily to charge my phone with a micro usb cable. This adapter has proven very reliable. TechMatte also contacted me today to make sure all my adapters still worked, so that that nice of them.
5 Stars By TechOutside on 2016-08-07
Money Saving Adapter
Excellent product! I use it on a daily because I always seem to leave or misplace my charger for my Nexus 6p and my friends never have a usb-c type charger. This product attaches to the micro USB charger end without fault. I would certainly buy it again and again, but there's clearly no need because they last a long time and the small bag they are shipped in works great as a case for them. Just keep them in the bag, slide the bag in you wallet and you will always have them when you need them.
Can be lost if not careful