Renesas Electronics Develops RF Transceiver Technology for Bluetooth® Low Energy
BLE is widely used in battery-powered equipment such as wearable devices and even lower current drain is now strongly desired for longer battery life. It is also necessary to reduce the number of external components to make this equipment even more compact and even lighter. This newly-developed Renesas RF transceiver technology is based on a low-power RF architecture acquired through a collaboration with the imec and Holst Centre and includes both newly innovated Renesas' unique transceiver filters and a new calibration circuit. By integrating the DC/DC converter, Renesas achieved the industry's lowest current drain levels: 2.1 mA during reception and 3.6 mA during transmission.
Key features of the newly-developed RF transceiver technology:
(1) Built-in impedance matching network and transmit/receive switch with no degradation of device characteristicsThis device integrates in the IC itself the transmit/receive switch that was previously implemented with external components and, since this can cause degradation of the receiving signal noise level and transmission power characteristics, Renesas adopted a newly-developed parallel structure switching circuit to minimize such degradation.
(2) On-chip reuse transmission and reception filters reusing impedance matching networkSince the impedance matching network and transmission and reception filters use inductors and capacitors, integrating these passive devices on the IC chip increases the chip area significantly. In this newly-developed circuit structure, however, it is possible to reuse the devices used for the impedance matching network. This made it possible to integrate the filters on the chip using a small number of devices. During transmission, the impedance matching network operates as an HD3 spurious signal rejection filter, and during reception, it operates as an image frequency rejection filter, such as configurable operation.
(3) Improved HD2 spurious calibration technologyRenesas' newly-developed spurious calibration technology eliminates HD2 spurious signals using a calibration circuit with improved spurious detection block. This also makes the design more resistant to manufacturing variations.
The RF transceiver was designed using a 40 nanometer (nm) process technology and supports BLE, which is the standard most widely used in healthcare and fitness products as well as wearable ones. Renesas achieved a RF core area of 1.1 mm2, by switching to a reusable device structure in the transmission and reception filters, while integrating the transmission and reception switch, the impedance matching network, and the transmission and reception filters on the chip. The minimum reception sensitivity is ?94 dBm (the standard requires ?70 dBm or lower) and the image frequency interference is ?20 dB or higher (the standard requires ?30 dBm or higher).
The newly-developed RF transceiver technology will not only lead to lower power equipment, but also, due to the reduction of external components related to the antenna, contributes to system miniaturization, cost reduction. These will be the keys for providing “Easy-to-Use” BLE user application systems since component adjustment no longer becomes necessary.
Renesas announced this technology on February 24 at the International Solid-State Circuits Conference (ISSCC) held in San Francisco held from February 22 to 26, 2015. This press release is based on the ISSCC paper number 13.4, titled “A 6.3 mW BLE Transceiver Embedded RX Image-Rejection Filter and TX Harmonic-Suppression Filter Reusing On-Chip Matching Network.”
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About Renesas Electronics Corporation
Renesas Electronics Corporation (TSE: 6723), the world's number one supplier of microcontrollers, is a premier supplier of advanced semiconductor solutions including microcontrollers, SoC solutions and a broad range of analog and power devices. Business operations began as Renesas Electronics in April 2010 through the integration of NEC Electronics Corporation (TSE:6723) and Renesas Technology Corp., with operations spanning research, development, design and manufacturing for a wide range of applications. Headquartered in Japan, Renesas Electronics has subsidiaries in approximately 20 countries worldwide.