Processor companion ICs with FRAM offer high-speed SPI

Ramtron International Corp. introduces its FM33x product family, a new line of FRAM-enhanced Processor Companion solution with a high-speed SPI.

The FM33x family combines, in one small package, all the benefits of a nonvolatile RAM with a set of highly integrated support and peripheral functions for processor-based designs. The product family includes FM33256 and the FM3316 parts. Both are 3V devices with 256Kbits and 16Kbits of FRAM, respectively.

Both single-chip solutions can replace discrete components and reduces cost and board space, supporting common system functions in processor-based systems such as meters and automotive telematics applications, said Ramtron.

The FM33x family incorporates a nonvolatile FRAM memory with No Delay writes, virtually unlimited endurance and low power consumption. The devices feature an operating voltage of 2.7-3.6V and works under the industrial temperature range of -40°C to 85°C.

Product features
The product family features an SPI bus that operates up to 16MHz, providing high-performance serial communication to the host processor. The devices also include a processor supervisor which provides two functions to the host processor—detection of power supply fault conditions and a watchdog timer to escape software lockup conditions.

Also included in the devices is an early power-fail interrupt function. The power fail comparator creates an NMI, warning the processor before the VDD drops out of specification. This is ideal for saving critical data to the FRAM.

With the devices' serial number function, a writeable, 64bit nonvolatile memory area can be locked once the serial number is set.

The RTC can be battery- or capacitor-backed for permanent powered operation. It offers a software calibration feature for high accuracy and an alarm. The products also feature a 16bit nonvolatile event counter with a programmable edge detector that can be used to log system intrusions (tamper events) and other events.

In terms of backup power, the RTC is intended to be "permanently powered," said the company. When the primary system power fails, the voltage on the V_dd pin will drop. When V_dd is less than 2.5V, the RTC (and event counters) will switch to the backup power supply on V_bak. The backup source can be either a battery or a capacitor.

Moreover, the devices feature a trickle charger that facilitates capacitor backup. The V_bak pin can optionally provide a trickle charge current. Data is nonvolatile so it won't be lost if the capacitor fails.

"The FM33x family was enhanced to meet the design requirements of the most advanced metering and car navigation systems," said Mike Alwais, VP of marketing at Ramtron. "Many of our metering and telematics customers have requested faster data collection capacity to support their need for higher data rates. This new integrated FRAM product family addresses their needs through a high-speed SPI bus that enables writes at maximum bus-speed."

Samples of the FM33x are currently available in a 14-pin SOIC RoHS-compliant package. Pricing for 10,000-unit quantities starts at $3.25 for FM33256 and $2.25 for FM3316.