Wireless microcontroller with novel Bluetooth LE radio

The chip is one of the firm's L78/G1D Group. "Current consumption of the RL78/G1D is among the lowest in the industry [3.5mA receive, 4.3mA 0dBm transmit]. Adaptable RF technology adjusts power consumption during wireless operation to the optimal level to match the communication distance," said the firm. "When wireless communication takes place at one-second intervals while maintaining a connected state with another wireless device, the BLE functionality can be added with the average current of 10µA."
According to ISSCC paper 13.4 'A 6.3mW BLE transceiver embedded Rx image-rejection filter and Tx harmonic-suppression filter reusing on-chip matching network', the transmitter uses direct 2-point PLL modulation and the receiver has a 'sliding IF' architecture, with an on-chip dc-dc converter to reduce power consumption.
A novel on-chip combined T/R switch / balun / filter (see diagram below) uses a switch in parallel with an LNA series inductor and digitally-controlled capacitors.
The switch is shorted for Tx mode - the input impedance of the LNA is relatively high impedance compared to 50Ω at 2.4GHz, and does not affect the transmit matching - and open for Rx mode.
In Tx mode, the network becomes an output pi-filter, and in Rx mode looks like an LNA input notch filter, with capacitor tuning rejecting image components around 1.46GHz.
The parallel switch arrangement is said to reduce signal loss by ~0.5dB, cutting power amplifier and LNA consumption by 10-15%.
For development there is an evaluation kit, Bluetooth-SIG qualified protocol stack, and PC GUI tool.
RL78/G1D MCUs wil be on show at Bluetooth Europe in London in September.