Touch MCUs with LDO operate at 150?A/MHz

Silicon Laboratories Inc. touts the lowest power touch-sense microcontrollers, breaking its own record, with the F9xx family, promising to extend the battery life of mobile devices at a lower cost than for previous entries.

Maintaining a 150?A/MHz operation (down from the previous record of 160?A) by virtue of an integrated low-dropout (LDO) regulator. The new family also claims to offer the lowest power in both active and sleep modes, as well as enabling touch-to-awaken functions. MCUs 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?s acquisition time. The sensitive CDC also supports proximity sensing for recognizing human gestures in addition to button, slider and rotary-knob emulation.

"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 1.5V battery," said Shahram Tadayon, MCU product marketing manager at Silicon Labs. "The new devices operate at full speed all the way down to 1.8V and are still ultralow-power like before, but now they also have a much lower price plus can fit into a smaller, 3mm x 3mm package."

The touch-sense MCUs operate at up to 25MHz using an 8051 core alongside a 12bit ADC, temperature sensor, voltage reference, 4x and 2- to 8KB flash. They are priced at less than $1 in volume.

- R. Colin Johnson
EE Times