Simplifying wearable device designs

17th November 2015

Toshiba

Joe Bush

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Whitepaper

Aimed for use in wearable devices, healthcare devices, smart phone accessories, sensors, remote controllers, beacons and toys, Toshiba Electronics Europe’s new Bluetooth ICs feature built-in Flash ROM, with one also adding the option of integrated NFC Tag functionality.

Both the TC35676FTG/FSG IC and TC35675XBG support Bluetooth Low Energy (LE) version 4.1 communications, while the TC35675XBG also supports NFC Forum compliant Type 3 Tag (Felica Lite-S compatible) communications. Both devices feature integrated GATT (Generic Attribute Profile) and support servers and client functions defined by the profile.

The number of Bluetooth Smart devices offering Bluetooth LE compatibility is growing and these ICs are intended to simplify their design. Both devices will help designers achieve lower cost designs as the built-in Flash ROM eliminates the need for external EEPROM and reduces the bill of materials and PCB size. In turn, this will facilitate the adoption of Bluetooth LE communications for small devices, such as wearable healthcare devices, sensors, beacons and toys.

The TC35676FTG/FSG uses a low power circuit design and integrates a DC/DC converter. The device integrates 192kB Flash ROM to store user application programmes and data to enable stand alone usage. The IC has a transmitter output power of 0 to -20dBm and receiver sensitivity of -92.5dBm.

In addition to the functionality provided by the TC35676FTG/FSG, the integrated NFC Tag circuitry in the TC35675XBG enables Bluetooth pairing and simple power on/off at the touch of an NFC supported smart device. The IC automatically generates Cyclic Redundancy Code (CRC) during writing to the Tag chip and provides automatic checks during data reads from the Tag chip. The TC35675XBG also adds additional SRAM memory as well as 2KB E2PROM.

The low power architecture of the ICs ensures they can operate for long time periods powered only by small coin cell batteries. The devices achieve peak consumption of less than 6mA (at 3.3V, -4dBm transmitter output power or receiver operation) and consume less than 100nA in deep sleep (at 3.3V).

The NFC Tag enabled TC35675XBG is available in a FBGA52 package measuring 4.5x4.5mm with a 0.5mm pitch, while the TC35676FTG/FSG is available in a choice of QFN40 packages measuring either 6x6mm, 0.5mm pitch (TC35676FTG), or 5x5mm with a 0.4mm pitch (TC35676FSG).