Ultra-low-power microcontrollers meet the fast growingdemand for energy efficiency, helping designers to extend the lifetimeof battery-operated products and to reduce energy consumption inapplications such as smart meters and domestic appliances. Commonpower-saving techniques include sleep modes and shutting off unusedparts of the chip, but ST’s EnergyLite technology also saves power whenthe device is active. This helps designers meet energy efficiencytargets such as ENERGY STAR 80 Plus, the international program thatpromotes more energy-efficient power supplies, as well as standby-powerlimits such as the IEA’s 1-Watt Plan.
The STM8L EnergyLite microcontrollers now available comprisethree product lines featuring ST’s advanced 8-bit processor core, whichhas an advanced architecture delivering high performance and efficiency.The STM8L101 line defines the entry point for the STM8Lfamily, providing up to 8Kbyte of integrated non-volatile Flash memoryand offering a choice of 20-pin, 28-pin and 32-pin low-cost,low-footprint packages.
The STM8L151 and STM8L152 lines add extra features includingup to 32Kbytes Flash density and up to 2Kbytes SRAM, externalcrystal/clock capability, enhanced reset features, and support forDirect Memory Access (DMA). Available peripherals include amotor-control timer, analog functions, real-time clock, and high-speedADC and DAC modules. In addition, on-chip EEPROM with true Read WhileWrite (RWW) capability saves complex and expensive emulation in Flash.The STM8L152 adds to these features by also integrating an LCDcontroller.
Family pricing starts with the STM8L101 4-Kbyte Flash versionin QFN20 3x3mm low-profile packages at $0.61 in quantities of 10,000.Further pricing options are available for larger quantities.
About EnergyLite technology:
ST’s ultra-low-power EnergyLite technology is based on a dedicated,proprietary 130nm process, which is optimized for ultra-low leakagecurrent. This significantly improves efficiency throughout static anddynamic modes, providing a low-power foundation for other energy-savinginnovations. In addition, low-power embedded non-volatile (Flash) memoryalso helps reduce the energy consumed whenever the microcontroller ispowered up. The Flash memory can also be turned off independently, toachieve a further significant reduction in microcontroller powerconsumption
An on-chip regulator ensures that power consumption isindependent of the supply voltage, which allows designers to optimizethe system power architecture without increasing the microcontroller’sconsumption. At the same time, EnergyLite technology permits the CPU tooperate up to its maximum frequency throughout the entire supply voltagerange from 1.65V to 3.6V. Integrated analog peripherals, also, arefully functional down to 1.8V, which can save the additional cost andpower overhead to provide a separate analog supply.
Like other ultra low-power devices, EnergyLitemicrocontrollers also make full use of clock gating to prevent unusedperipherals consuming power. There are also multiple power-managementmodes including a 5.1 microamp Low-Power Run mode, 3.0-microampLow-Power Wait mode, 1.2-microamp Active Halt with full Real-Time Clock(0.9 microamp with Automatic Wake-Up (AWU) and 350-nanoamp Halt mode.The device can wake from Halt within 4 microseconds, enabling frequentuse of the lowest-power mode. Low-power peripherals including the sub1-microamp Real-Time Clock and Automatic Wake-Up (AWU) unlock furthersavings.
The combined effect of the EnergyLite innovations, coveringchip fabrication, voltage/frequency regulation, and power management,allow the STM8L family to achieve dynamic current consumption as low as150 microamps per MHz.