SiLabs breaks low-power record for touch-sense MCUs

PORTLAND, Ore. — Silicon Laboratories Inc. (Austin, Texas) claims to have broken its own record for the industry's lowest power touch-sense microcontrollers with its new F9xx family, promising to extend the battery life of mobile devices at a lower cost than for previous entries.

"To reduce the cost of the microcontroller by about 20 percent, we reduced its flash memory size and removed the dc/dc converter that enabled operation from a single 1.5-volt battery," said Shahram Tadayon, MCU product marketing manager at Silicon Labs. "The new devices operate at full speed all the way down to 1.8 V and are still ultralow-power like before, but now they also have a much lower price plus can fit into a smaller, 3 x 3-mm package."

Maintaining a 150-microamp/MHz operation (down from the previous record of 160 microamps) by virtue of an integrated low-dropout (LDO) regulator, the new family also claims to offer the industry's lowest power in both active and sleep modes, as well as enabling touch-to-awaken functions. The microcontrollers can manage 14 touch-sensitive user interfaces on consumer and industrial devices, ranging from home appliances to smart meters, security systems, lighting, games and toys.

Silicon Labs provides its QuickSense library of common touchpad software routines for quickly prototyping and deploying capacitive touch-sensitive user interfaces. A patented capacitance-to-digital converter (CDC) is said to enable a 40-microsecond acquisition time. The sensitive CDC also supports proximity sensing for recognizing human gestures in addition to button, slider and rotary-knob emulation.

The touch-sense microcontrollers operate at up to 25 MHz using an 8051 core alongside a 12 bit analog-to-digital converter, temperature sensor, voltage reference, four timers and 2 to 8 kbytes of flash. They are priced at less than $1 in volume.