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Page 1 of 17
Here at Bazinga, we’re all fans of the latest and coolest gizmos and [smart]watches. So when LG
recently announced the new LG Urbane, I looked at the LG watch R on my wrist, purchased a mere few
months ago and went “What? It’s obsolete already?”
Ever since the explosion of smartwatch entrants in the market in recent years, the technological progress
that has gone into wearables has taught us all many lessons, with battery life and health monitoring among
the new possibilities this new frontier of technology brings us.
Smartwatch reviews online are aplenty, and the LG watch R has gotten coverage on TheVerge and Wired
as well as received a good review on Engadget. In my opinion, the watch has been a conversation starter but
beyond that, its utility is debatable. Third-party apps can cause the watch to crash, forcing one to restart the
device. While it may not be due to the hardware itself, this can really be irritating and there have been
instances when I ended up pulling out my phone to check the time.
There were also times when I couldn’t trust the time on the watch because it crashed and reset itself. “It’s
10.30am. Wait. 10.35am? No it’s not.. it’s.. dammit, my watch restarted itself.” Once, the running app
crashed and I lost track of my run mid-exercise.
Other than the initial kinks, this little buddy has turned out fine so far. Battery life isn’t too bad; the watch
can last for just about two days with moderate usage before charging is required. Till the next smartwatch
wins its place on my wrist, I must say the LG watch R is a well-made and engineered gizmo with a clear and
responsive high-resolution screen. To give it credit, we should find out what makes it tick. A quick search
showed that a teardown was done on the LG watch R’s predecessor by iFixit, but not on the R itself.
What makes this little guy tick?
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Page 2 of 17
The four Torx T5 screws were easily removed,
revealing a very simple plastic back plate and a
single-PCB.
The first thing I noticed was how neatly
organized the board is and how much empty
space there is on the PCB. At first glance you
can see the various flex-PCB connectors neatly
placed at the corners and edges of the main
PCB.
That is a good practice; one reduces cost on
unnecessarily long flex-PCBs that would cover
up precious real-estate on the PCB.
Let’s take a closer look at the populated
components.
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The most prominent component in the centre of the PCB is an optical photoplethysmograph (PPG) heart-
rate sensor, which is fast gaining popularity in smartwatches for bio-measurements. For the LG watch R, the
heartrate sensor is a Taiwanese1 PixArt PAH8001 featuring an integrated pixel Array plus green LED sensor
in a 3 x 5mm SMD package with a low power consumption of 1.5mA. The full datasheet is available here.
If you are looking to build your own smartwatch with photoplethysmograph (PPG) heartrate sensors,
there are a variety of alternatives to choose from. Maxim’s MAX30100, JRC's NJL5501R or NJL5310R
COBP photo-sensor and OSRAM’s SFH 7050.
On the bottom right of the main picture we can see Alps
electric Digital Pressure Sensor HSPPAD Series, model
D38 JCH8. The low current consumption (9.5μA) makes it
suitable for a wearable application like this. Plus, the
measurement range is rather wide, at 300 to 1100hPa or
4.35 to 15.95 psi.
These units are quickly calculable - on earth; standard
atmospheric pressure is 101.325kPa = 1ATM (1
atmospheres), so 300hPa = 30000Pa = 30kPa = 0.296
ATM, and 1100hPa = 110kPa = 1.086 ATM. This sensor
has a range of 0.3 to 1.086 atmospheres.
Right beside the Alps altimeter is the InvenSense MPU-
6515 6-axis accelerometer + gyroscope. It features
MOTIONTRACKING™ SoC Optimized for Google’s
Android KitKat 4.4 and has an on-board Digital Motion
Processor™ (DMP) which offloads motion algorithms
without requiring computation from the main MCU. It
features a small footprint of 3x3x0.9mm.
Designed for low-power operation, Vcc is at 1.8 volts and
consumes only 6.1mW of power in full operating mode, or
about 3.4mA.
1 http://www.pixart.com/index.asp and http://www.richtrend-tech.com/product/showproduct.php?lang=cn&id=17
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At the bottom edge, we have the AKM semiconductor
AKM8963 H417D compass, a 3-axis electronic compass
with a high sensitive Hall sensor with a measurement
range of ± 4900 μT.
16-bit resolution gives it a sensitivity of 0.15 μT/LSB and
average current at 8Hz repetition rate: 280μA typical.
The MPU-6515 and the AKM8963 combination give it a
very nice 9-DOF (Degree of Freedom) with only 3.68mA
of power consumption.
Beside the InvenSense gyroscope and above the compass,
we have a Synaptics Synaptics ClearPad™ Touch
controller, model S3526B 43310013. No datasheet seems
to be available but it’s possibly ClearPad Series 3 from the
“S3526” markings.
The Series 3 allows up to 10 touch points on a screen not
exceeding 6” in size. Product brief here, alternative series
3 controllers you could use are S3402B, S3204 or S3250.
If you are looking to utilize small touch-screen controllers,
other manufacturers include Melfas 8FM006A, Cypress
TrueTouch®, Atmel, STMicroelectronics , Microchip
mTouch, Silicon labs C8051F76x and Elotouch.
What’s interesting is that while international IC players such as Atmel, Cypress and Synaptics are now
dominating the global touchscreen controller IC market. Melfas, Zinitix and Imagis Technology are
emerging as the leading vendors in South Korea. More options are now available to developers!
There’s a missing component here, with the typical array
of surrounding BOM, decoupling caps, maybe a protection
diodes. Could be an alternative accelerometer / gyroscope
sensor if the latter was not available at the time of
manufacture.
It is a good practice for a designer to include sufficient
real-estate space for potential logistics issues, one wants to
be able to use an alternative component and not let that
single component create manufacturing delays for
components that have drop-in replacements, and then a
simple firmware update and one doesn’t have to go
through another round of PCB revisions.
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As we move clockwise-left, here we have ON
Semiconductor’s USB2.0 DPDT switch. This component
is a differential DPDT (Double Pole Double Throw) high-
speed USB2.0 480Mbps switch in a tiny UQFN10 casing.
The (AT-K) markings tell us it’s the NLAS7222C 2-to-1
port analog switch. We can see it’s a type “C” because
pin 3 on the right is routed to ground, with pins 4 and 5
going to a tented via (vias covered by solder mask), which
on the datasheet is HSD2+ and HSD2-.
Signal data routing inputs from USB go through an EMI/RF filter array at the bottom. Below, on the bottom
right could be an EMI filter array to suppress conducted interference that is present on a signal or power
line which makes sense coming from the D+/D- of a USB port. Most EMI filters consist of components that
suppress differential and common mode interference.
Alternatives for this component are: TI’s TS3USB3200, NXP’s NX3DV42, or Intersil’s ISL54228.
The great thing about such components for designers are that one can now look at price to reduce overall
cost, or if manufacturers have drop-in alternative preferences, no down-time is lost on design revisions.
Next we see an Imagis technology ISOA1423 single
supply Haptic driver. Its Imagis ISA1000-series group of
haptic drivers work with most ERM (Eccentric Rotating
Mass) and LRA (Linear Resonant Actuator) type
actuators.
Pins 8 and 5 (top left and right) connect to the E0830
ERM vibrator on the top PCB layer. It’s nice to see such a
versatile haptic driver in one IC package.
As for the vibrator… Lots of these are from Chinaland.
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Page 6 of 17
Common in today’s multi-stacked modular PCB designs
are such board-to-board connectors.
The Hirose DF-series is a selection of board-to-FPC
connectors, with 0.4mm pitch and a really low profile of
0.98mm mated height. Alternatives include Molex’s
SlimStack™ Fine-Pitch SMT Board-to-Board Connectors.
What was especially interesting was the Hirose BM22-4S-
V(53) Mezzane connectors, this has a really high power
rating, 30V, 4A!
It’s designed especially for slim-stacking battery units
with a secure fit. Very nice indeed.
We now come to LG’s custom screen, and our unit has the
LH130Q01-ED01-QG1 Ver 2.4. The specs tell all, a 1.3”
Full Circle P-OLED with 320 x 320pixels at 246 ppi.
No datasheet is available since it’s not for OEM sale, and
scrutiny under the microscope shows very intricate
construction layers, with the capacitive touch screen
layered directly onto the P-OLED screen itself.
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Also of note is that LG has chosen to go with the same surface areas for each colour sub-pixel instead of a
reduced surface area for green. The top pictures show the powered and unpowered state of the pixel
arrangement. A very impressive piece of engineering, vibrant colours on a semi-transparent substrate in a
thin package with excellent contrast ratio. Learn more about AMOLEDs here. Manufacturers of AMOLEDs
are now led by LG Display, Samsung, AMOLED corp and Ignis Innovation.
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Page 8 of 17
Charging cradle contacts are your stamped/formed gold-plated metal contacts, no surprises here. A
flexible PCB consists of the charging contacts and a membrane tactile vertical push-button with metal
shielding.
With that, we can more or less conclude the fairly simple construction approach for the battery cradle
and internal support structures.
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Now this is interesting, the antenna network goes to a gold pad, which then goes to the gold metal
contacts of the plastic assembly, and that contacts the external casing of the watch itself by an un-anodized
exposed pad, which means the entire bezel/casing of the watch is the antenna contact to the Broadcom chip.
Now, we take a look at the other side of the populated PCB. The EMI shield came off fairly easily.
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Page 10 of 17
Removal of the EM shielding cover from the surrounding mounting clips was a breeze, it wasn’t soldered
down and the ground traces were very clear. The three main visible chips under the shield are Qualcomm’s
PM8226 Power Management IC, Broadcom BCM4343W communications chip and Hynix-Qualcomm
Multi-layered APQ8026 SoC NAND memory (exposed by the shield).
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Here is the Broadcom BCM4343 WKUBG
The BCM4343 is an integrated combination chip (Wi-Fi
2.4Ghz 802.11bgn, 4.1/Bluetooth Smart, wireless charging
and FM radio and even A4WP wireless charging and FM
radio. According to reports, the BCM4343 family has
three packages comprising of the BCM4343S, BCM43438
and BCM4343W, each for different applications.
The BCM4343W is designed for wearables with a
GCI/UART interface connected to the sensor hub allowing
the sensor hub to work directly with the 4343W and
bypassing the main MCU – leading to lower power
consumption. The Wi-Fi is controlled by an ARM CR4
core, and the Bluetooth by an ARM CM3 core.
A cross-angled perspective of the really low-profile WLCSP; look at the surrounding 0402 passive
components. We can appreciate that this is one tiny chip requiring precise reflow soldering. It is an
impressive communications chip; unfortunately LG still denies that the R is capable of utilizing Wi-Fi.
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Hynix H9TU32A4GDMC-LRKGM
The Hynix H9TU32A4GDMC-LRKGM is a multi-chip
package, 4GB eMMC NAND (user available memory up
to 3 GB), 512MB RAM mobile DDR2.
The Qualcomm® Snapdragon™ 400, 1.2GHz SoC is
hidden beneath this DRAM chip. It integrates four Cortex-
A7 MPcore Harvard Superscalar cores at up to 1.2 GHz
(Quad-Core) and an Adreno 305 graphics card at 450
MHz.
Development kits are reported to be available soon.
Fairchild Semiconductor FTL11639UCX UCAE EFP
This is interesting; it’s a configurable Load Switch and
Reset Timer. The FTL11639 is both a timer for resetting a
mobile device and an advanced load-management device
to add a fixed delay of 11.5s prior to disconnecting the
PMIC from the battery.
Useful for conditions where one does not want to shut off
power to the MCU immediately after the power button is
pressed, instead to initiate a shut-down sequence, or vice-
versa.
Texas Instruments BQ27421-G1
Ah, the BQ27421-G1 is the Battery fuel gauge with
integrated sense resistor which provides information such
as remaining battery capacity (mAh), state-of-charge (%),
and battery voltage (mV).
A must-have for battery-powered devices these days.
Alternatives include Maxim’s MAX17050, Maxim
MAX17043, ONSemi’s LC709203F, Linear’s multi-cell
LTC2943 which are available from all major chip
manufacturers.
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Texas Instruments TPS61282
A decent Power Management Unit (PMU), the Texas
Instruments TSP61282 is a battery front-end DC/DC
converter, Synchronous Boost-bypass power supply for
single-cell portable applications such as this wearable.
Its efficiency is up to 95% at 2.3MHz and accepts a wide
VIN range from 2.3V to 4.8V and adjustable current limit
dynamic voltage scaling.
Qualcomm’s WCD9302 audio codec DAC
No detailed datasheet was available for this particular
component, but we noted that the Samsung Galaxy S3,
Sony Xperia S, HTC One-S and Pantech IM-A850L use
the Qualcomm WCD9310 DAC.
An alternative is Cirrus Logic’s WM1811 (formerly
Wolfson Microelectronics), a nice 24-bit dual-channel
DAC one could use to develop projects with.
Knowles acoustics S1301 2137 microphone
We now come to this component, which is undeniably a
microphone, but no datasheet is available based on the the
markings. Given the markings and the component design
footprint, we think it’s a Knowles acoustics MEMs
microphone. The brand has a whole range here.
Alternatives include SPM0406HE3H, Cirrus-logic,
STMicroelectronics and InvenSense.
Lithium-polymer battery, LG BL-S3 410mAh
This is one well-made battery, and some research revealed
that it’s manufactured by Technohill (Yantai)-Ltd, which
could be the Chinese contract manufacturer for LG’s
battery division. The company specializing in SMT for
battery manufacturing and camera modules used in mobile
phones is LG Electronics. Headquartered in Bucheon,
South Korea, China has established subsidiaries in Yantai.
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Its measured volume is 4.16 x 29.3 x 27.7 = 3376.30mm2,
the energy density is thus calculated to be 121µAh /mm2.
That is surprising since it’s comparable to the low-cost
lipo batteries that we have in the lab. 4.5 x 18.2 x 24.2 =
1981.98mm2
or 121µAh /mm2.
The energy density is the same! Looks like the same
typical prismatic packaging and lithium polymer
chemistries, nothing new here.
We’ve come to the end of this teardown. Although adoption by the masses seems limited, lessons can be
learnt from the relatively impressive Bill-of-Materials (BOM) from the tear-down. As the technology
improves, it’s likely we will see wireless charging, more WCSP and multi-die chips in the next generation of
wearables.
As is the case with the LG Watch Urbane, wearables are gradually improving in both form and function.
This watch looks the part, has all the specs you'd hope for in a device of this nature, and wouldn't look out of
place on the wrist of a businessman. But that doesn't mean it will sell - Android Wear is still too nascent a
platform, with too many limitations, to be considered as a viable choice right now.
Like what you see? Have a platform you want to learn about? We have IPC-CID+ and electronics
professionals on our team and we provide in-depth teardown and investigative report services. Bazinga!
