STMicro unveils fast-write memory for black-box recorders
June 30, 2011 by John Day
STMicroelectronics has introduced a new memory with a unique ultra-fast recording feature for storing important data during unexpected events. Its uses include ‘black-box’ recorders that help identify the causes of equipment failures or accidents.
A system using the M35B32 EEPROM can store a significant amount of vital information (2 Kbits) in less than one millisecond, and hence can react when the onset of a system failure or an accident is detected. Compared to alternative non-volatile memories, the M35B32 is about forty-times faster than a standard 32-Kbit EEPROM and matches the write speed of Flash. Consuming approximately one-tenth the energy of Flash, ST’s new memory allows designers to specify a voltage supply backup capacitor of one-tenth the size needed to operate the memory long enough to finish writing if system power is lost unexpectedly. This translates into significant savings both in cost and printed-circuit-board area. The M35B32’s EEPROM technology also has cost and quality advantages compared to high-speed FRAM technology.
The M35B32 has a 32-Kbit capacity, which is divided into two sectors for event recording and regular system EEPROM. The sector sizes are user adjustable to suit various application requirements. The large page size of 256 bytes allows a large amount of data to be written in a single page-write cycle and, when addressing the event recording sector, this information can be programmed in less than 1ms. This enhances system performance and saves software overhead. The M35B32 is accessed via a standard SPI serial connection, and so can be used as a direct replacement for standard SPI serial memories.
The M35B32 is in production now, in SO8N, TSSOP8 and FPN 2 x 3mm compact surface-mount packages, priced at $0.65 for 1000 pieces. Alternative pricing options are available for larger quantities. Automotive-qualified devices will be released at the beginning of 2012, and will simplify the design of equipment such as vehicle ABS.