Renesas – RX111: Ultra-Low Power Solutions for Battery-Powered Technology



Handheld remote control devices have to run on batteries as long as possible, with a typical goal of four years before replacement. As a result, reducing power consumption is a major system design issue. For handheld applications, system design factors include: the amount of time the application spends in active mode, the amount of time the MCU spends in the low power mode, and the current-drain characteristics of the system’s MCU.

These factors are critical in determining battery life, and the RX111 is an entry-level 32-bit MCU that was designed from the ground up to offer the best power management options for handheld developers. For example, the RX111 can “snooze” in Software Standby mode and consume only 350nA. Just as important, the RX111 can wake up from this mode in 4.8μs – allowing the MCU to quickly and efficiently update the time display on the remote, respond to keypad inputs or monitor battery status, and then return to sleep mode, minimizing the amount of current drain on the battery. Here the flexibility of the RX111 power-down options stand out, for if the application requires an even shorter wake-up time, the RX111 also offers a Sleep Mode and Deep Sleep mode that reduce the delay to 1μs or less.

Even when operating in run mode, the flexibility of the RX111 power options proves beneficial. The RX111 offers three different operating modes that can be applied according to the application requirements at any point in time: high speed run mode, middle speed run mode and low speed run mode. And, with the RX111, peripherals that aren’t required can be completely shut down in every mode, while a flexible clock system allows peripherals to use a clock frequency from the same clock driving the CPU to
achieve the lowest level of power consumption.

So the answer to the challenge of maximizing battery lifetime in handheld and remote control designs is clear – the RX111, which offers the best power down options of any 32-bit MCU available today.

Low Power Consumption, Fast Wake-up
Software Standby achieves a power consumption of only 350nA, with a 4.8μs wake-up time. Applications requiring a shorter wake-up can utilize the Sleep and Deep Sleep modes that reduce the delay to just 1μs.


Run ModeICLK FrequencyInternal Voltage Regulator Mode
High Speed 8MHz - 32MHz High Power
Middle Speed 1MHz - 8MHz Middle Power
Low Speed 32kHz - 1MHz Low Power


RX111 Renesas Promotion Board (RPB)
The board was designed to showcase RX111 low power modes, featuring Pmod and energy harvesting connectors, and comes loaded with software and tools.

  • Integrated J-Link debugger
  • Power measurement built in
  • Applilet
  • e2studio toolchain
  • USB Demo

RPB Part Number:


RX111 Renesas Starter Kit (RSK)
This complete RX111-based hardware/software platform for in-depth application design includes the E1 Debugger, a trial version of the e2studio and Renesas RX compiler and demonstration firmware.

RSK Part Number: