Power Saving Solution for Implementing Fine Grained Control of Automotive Powertrains

Renesas Technology America, Inc. today introduced the SH72531, a 120MHz 32-bit SuperH® microcontroller (MCU) that integrates 1.25 megabytes (1.25MB) of flash memory. It can implement the fine-grained control of automotive engines and transmissions needed to achieve smooth, powerful performance and high efficiency with low emissions. Built with the same 90-nm process as the successful 200MHz SH72544R introduced in July 2008, the new MCU is value engineered to cost less and consume less power, while meeting industry requirements for high reliability and operation at temperatures as high as 125°C.

Amrit Vivekanand, marketing manager, automotive business unit, Renesas Technology America, said, “By applying our 90-nm process technology and exploiting our automotive industry expertise, we have created a powertrain control system solution tailored to the requirements of smaller, less expensive vehicles. The SH72531 is slightly less powerful than the SH72544R and provides fewer features to reduce system costs and power consumption. Nevertheless, it offers the functions and performance needed by the innovative vehicles that will be launched in the next few years in fast-growing lower-end global markets.”

The SH72531 has the same SH-2A high-performance 32-bit CPU core with a floating point unit (FPU) as the SH72544R for full software compatibility, and achieves 240 MIPS processing performance at 120MHz. Yet the 3.3V/5V chip consumes just 350mW.

The SH72531’s 1.25MB on-chip flash memory operates at 100MHz speeds, but works in conjunction with a low-power cache to deliver performance roughly equivalent to single-cycle access at 120MHz. Furthermore, 32 kilobytes (32KB) of that flash is allocated for data storage and can be overwritten while the MCU is operating. The flash provides roughly the same functionality as EEPROM and eliminates the need for external memory that increases system cost.

Peripheral functions that match actual application requirements make possible a compact (24mm x 24mm) LQFP package with 176 pins, 35 percent fewer than the SH72544R. The functions and interfaces that enable highly precise real-time control of engines and transmissions include the ATU-III multifunction timer, a fast 12-bit A/D, a CAN* interface, and a high-speed serial interface.