Nordic Semiconductor has cut the power consumption of its nRF8001 Bluetooth 4.0 low energy IC, as well as upgrading its Bluetooth software stack.

The revision - called the nRF8001 'Build D' - is hardware and software drop-in compatible with the current (Build C) revision.

"The new power saving features and enhanced Bluetooth stack are easily accessible through an expanded application controller interface (ACI) command set that can be used by extending existing application code.

Stack features required for the Bluetooth low energy human interface device (HID) profile have been added, allowing the chip to be used in wireless PC peripherals and navigational remote controls for connected TVs and set-top boxes.

The nRF8001 has an on-chip +/-250ppm 32kHz oscillator, and power saving comes partly from 'dynamic window limiting'.

"For Build C, there was a potential power consumption penalty of running on the internal +/-250ppm 32kHz RC oscillator versus an more accurate - typically +/-20ppm - external crystal for connection intervals of longer than about 1s. Below 1s the difference was negligible," said Nordic. "The dynamic window limiting feature in Build D mitigates this penalty. Running on the +/-250ppm RC oscillator will consume similar amounts of power to running on an external crystal over sub-1s and over 1s connection intervals."

The technique does not depend on any special features in the peer device.

Further power savings come from a feature called 'application latency', which also need no modification to the peer device.

"Application latency reduces latency for data from the central to the peripheral device in a connection using slave latency," said Nordic. "The reduced latency means that developers can take advantage of higher slave latency while at the same time meeting all required data latency requirements, yet achieve power savings of up to 30%."

Stack enhancements include: support for authenticated pairing while in bonding mode; application initiation of security request while in bonding mode; broadcast of data, plus Direct Advertising.

Samples and updated Development Kits are available now, with volume production scheduled for February next year.