Stylish fitness tracker features OLED screen

At 15mm wide, the Alta is both slimmer and lighter than its predecessors and with its many interchangeable band options and the glossy colour OLED screen, it is a thing of beauty. While it is marketed as a much as a fashion accessory as a fitness tracker, it is not just a bracelet (actually, Fitbit seems to be careful to call it a 'wristband'), it does have a function too. Let’s have a closer look inside to see what makes this Fitbit 'tick'.

Before we open it up, we already know what we will not find in this device. Unlike its predecessor and price-twin, the Fitbit Charge, the Alta does not include a heart rate monitor or altimeter. Otherwise, it appears to be quite similar. The majority of the data required for the Alta to perform its duties comes from the STMicroelectronics LIS2DH 3-axis accelerometer. This linear accelerometer belonging to the 'femto' family, is the very same Chipworks has found in the Charge, Charge HR, and Surge products, as well as other wearables by Garmin and Misfit. 

If you have read reviews of the Alta, many of which describe the colour OLED as a touch screen, you might also be expecting to see a touch controller. Our teardown confirms there is indeed no touch controller, indicating that Fitbit’s description of a 'tap' screen is quite purposeful. This tap function is likely driven by the Alta’s only sensor, the accelerometer. To sync and communicate with the devices that will display the user’s data, the Alta again employs a STMicroelectronics part. The BLUENRGCSP is a Bluetooth specification v4.0 compliant, slave single-mode Bluetooth low-energy network processor.

Also provided by STMicroelectronics are a BALF-NRG-01D3 ultra-miniature balun and the STM32L485JC MCU. The balun has been spotted once before in the ASUS VivoWatch, but the MCU is 'new' to Chipworks. STMicroelectronics describes STM32L4 MCU series devices as ultra-low-power and flexible, citing an ARM Cortex-M4 core with up to 1Mb of Flash memory and up to 128Kb of embedded SRAM.

By now, you may be noticing a pattern: the Alta seems to be a huge win for STMicroelectronics, providing four of the five silicon devices we have identified. The sole exception: the Maxim, a wearable-optimised Li-ion power management IC.

Diving even deeper into Chipworks’ expertise, we have also produced a landscape of Fitbit’s patent portfolio using Chipworks Patent Analytics Solution Powered by KMX. These patent landscapes are topological representations of groups of patents. They are generated using the words within the patent text. Peaks in the topology represent a group of patents that are very similar. The words on top of this peak are the three most used words in the text of these patents and represent the technology area – but are generated automatically (so they may seem out of order to us sometimes). The distance between peaks is a representation of how different two technology areas are. If they are close together, they are similar. If they are far apart, they are very different.

Fitbit wearables are considered part of the IoT sector. The wristbands are sensor systems which are synchronised to the cloud. Inspecting the landscape, we see the core of their patent portfolio consists of wireless pairing to provide messages about biometric goals (peaks starting with message… and weight) – sounds like Fitbit! The five spokes of the landscape surrounding these core patents address five different domains: how their product looks (ornamental); sensor technology (altitude); architecture of wristband biometric measurement systems (ephemeris); higher level services using GPS (geo); and the heart rate sensor light (heart).

Since the beginning of its consumer availability in early March, Fitbit reports that over 1m units of the Alta have already been shipped, again emphasising the size of this win for STMicroelectronics.