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Inside the Xiaomi Mi-2: familiar outside, different inside

The Xiaomi Mi-2 – a bit overdue, but worth the wait

Since the focus of our teardown articles are typically interesting  new technology, the weeks and  leading up to the holiday season keeps us very busy going inside 5-6 new devices per week. Sometimes things get lost in the shuffle.

One such thing is giving you a look at the Xiaomi Mi-2 that has been out of our teardown lab for a few weeks now.

The “what, what-what” you say?

The Xiaomi Mi-2 is a hot new phone for the Chinese market and the first run on this phone sold out in under 3 minutes.

Xiaomi is a relative newcomer, but one that is intent on dominating its piece of the world with a combination of value pricing, hot specifications, and just enough premium bits to make the average consumer take notice.

Xiaomi Mi-2 Phone
Xiaomi Mi-2 Phone
What separates this phone from phones twice its price?

From the exterior shots we can’t help but draw the obvious comparisons with a certain market-leading phone. While we are the first to admit that you can’t do all that much different with a large touch screen, we can also admit that the rounded edges, the size and shape of the bezel, the sides, and the microphone port all feel a little familiar.

Since we are drawing comparisons, then lets look at the battery too. Apple has (oddly) always had a somewhat sexy looking battery – if you are into that type of thing. Xiaomi has gone a flashy route in a battery that is a little hard to spot at first blush.  Look hard to find the orange rectangular thing at the right. This battery provides 7.4Wh so no loss there versus most other phones.

FYI – The other orange thing not on the main board is the touch screen control courtesy of the market leading Atmel MXT336S – designed for screens up to 5.5″ with 336 nodes.

Xiaomi Mi-2 Teardown - Back off
Xiaomi Mi-2 Teardown - Back off image 2
Xiaomi with Atmel Touch Screen Controller

A look at the major silicon

Okay – the first thing to note is that the approach to board design is not the most modern and the result is a phone that is a bulky 10.2 mm thick. Shields are built into the back and the way they have been implemented would conceivably provide structural rigidity. It is also one-sided.  But systems analysis aside, here is the major silicon showing Qualcomm to be a major winner by providing the chipset solution:

  • Qualcomm MDM 8215 Baseband processor with PM8821 & PM8018 power management
  • Qualcomm WCN3660 WiFi SoC
  • Qualcomm WCD9310 Audio CODEC
  • Audience eS310B Audio Processor
  • Toshiba THGBM5G8A4J 32 GB NAND Flash
  • STMicroelectronics L3G4200D Gyroscope
  • Bosch C3H Accelerometer
  • Knowles S932 MEMS Microphone
  • AKM AK8963 Hall Effect Sensor (compass)
  • Texas Instruments TPA2015D1 Audio Amplifier
All of these suppliers (and chips) are the usual suspects with design wins in most of the flagship phones on the market today. No second-rate chips to be found.

Xiaomi Mi-2 Teardown - Back off image 2
Xiaomi Mi-2 Teardown - circuit board

Looking closer

First off, the heralded Qualcomm Snapdragon S4 (low res only at right). This puts the phone right up at the top of the processing ladder for a price that one would expect to pay for last generations phone. Memory is courtesy of Elpida (2 GB) in a modern PoP design. No compromises here.

The camera is the Sony IMX145 back-illuminated 8 Mp design found in the iPhone 4S and Samsung Galaxy S3. The secondary camera is the OmniVision OV2A9BA. No compromises here.

The touch screen itself is a modern HD IPS display from Sharp and delivers higher (1280 x 720) resolution that most other phones on the market today considering the 4.3″ screen. No compromises here.


Qualcomm Snapdragon 4

Qualcomm Snapdragon S4 Polysilicon Die Photo

Sony IMX145 Polysilicon Die Photo

So to conclude the main compromise seems to be the layout of the board and resulting size of the phone. If you demand performance without the cost that comes from the pizzazz then this may be the phone for you.

Analysis on devices found in the Xiaomi Mi-2

Qualcomm Snapdragon S4 Functional Analysis Report

Sony IMX145 CMOS Image Sensor Imager Process Review and Circuit Analysis Reports