Infineon Technologies FM31256-GTR

Infineon FM31256-GTR Processor Companion Series Product Summary

The Infineon FM31256-GTR is a highly integrated processor companion IC aimed at designers of processor-based embedded systems who prioritize robust nonvolatile memory, real-time timekeeping, and advanced supervisory functions. Originating from Cypress' legacy and now fully supported by Infineon Technologies, the FM31256-GTR combines ferroelectric RAM (F-RAM), a real-time clock, and various essential system monitoring peripherals inside a single compact 14-pin SOIC package. Its comprehensive feature set effectively consolidates components and reduces board complexity for engineers seeking efficiency and reliability.

Top Functions of Infineon FM31256-GTR

The FM31256-GTR’s feature set is centered on an advanced 256-Kbit (32K × 8) F-RAM array offering exceptionally high cycling endurance and data retention. The device also integrates a real-time clock/calendar, low-voltage detect and reset generation, programmable watchdog timer, battery-backed nonvolatile event counters, a lockable 64-bit serial number space, and a programmable power-fail interrupt comparator. All functions are accessible via a standard I2C serial interface with support for frequencies up to 1 MHz and four device addresses for multi-component applications. These capabilities streamline embedded system design by replacing multiple discrete components with a single IC.

Memory Design and F-RAM Technology in Infineon FM31256-GTR

At the heart of the FM31256-GTR lies its ferroelectric random-access memory (F-RAM), providing true nonvolatile RAM functionality. The 256-Kbit array is organized in 32,768 × 8 bits and supports two-byte I2C addressing, ensuring compatibility with standalone memory solutions. F-RAM offers no-delay, unlimited write endurance (rated at 1014 cycles), and robust data integrity with up to 151-year retention. Engineers can take advantage of software-configurable memory protection zones, enabling secure partitioning by bottom quarter, bottom half, or the entire array. Such characteristics make the FM31256-GTR ideally suited for applications where frequent data logging or dynamic parameter storage is required—without the reliability concerns associated with EEPROM or flash alternatives.

Real-Time Clock Capabilities of Infineon FM31256-GTR

The integrated real-time clock (RTC) delivers timekeeping in BCD format, tracking from seconds to centuries with leap year adjustments through 2099. It operates using a standard 32.768 kHz crystal, with hardware and software time calibration for accuracy. The RTC supports dedicated battery or supercapacitor backup via the VBAK pin, maintaining time and calendar information during power loss. In advanced scenarios, the RTC’s calibration mode provides a 512 Hz reference output for fine-tuning oscillator performance—a useful feature during manufacturing or system setup.

Processor Monitoring and System Dependability with Infineon FM31256-GTR

System reliability is enhanced through the FM31256-GTR’s processor supervisor functions. The device offers active-low reset output, precisely controlled by programmable VDD thresholds and watchdog timer activity. Engineers can configure the reset voltage trip point to four levels (2.6V, 2.9V, 3.9V, 4.4V), tailoring response to specific supply tolerances. The watchdog timer, programmable in 100 ms increments (100 ms to 3 seconds), provides a safeguard against software stalls or lockups. Manual reset functionality is also included, featuring input de-bouncing and filtering for robust response to user input. Source flags for reset events allow software to distinguish between power-related and watchdog-induced resets, an essential diagnostic feature for fault-tolerant systems.

Event Tracking and Serial Number Support in Infineon FM31256-GTR

The FM31256-GTR incorporates two battery-backed event counters, each with programmable edge detection via dedicated input pins. These counters are ideal for tracking critical system events such as intrusions, tamper detections, or operational cycles—even when main system power is lost. Cascading is supported, allowing extension to a 32-bit counter for increased capacity. Complementing security is a programmable 64-bit serial number area, which can be locked against further writes for permanent device identification—a vital tool for asset tracking, anti-counterfeiting, and regulatory compliance.

I2C Communication and Integration Factors for Infineon FM31256-GTR

Communication and control for all FM31256-GTR functions is accomplished over an I2C interface supporting legacy (100/400 kHz) and fast (1 MHz) speeds. Address select pins permit up to four FM31256-GTR devices on a single bus. The open-drain SDA and SCL pins are fitted with Schmitt triggers for noise immunity and controlled output slopes to minimize signal ringing. For optimal integration, engineers should ensure correct pull-up resistors on the bus and follow best PCB layout practices as outlined in technical documentation to maintain analog signal integrity on crystal and comparator inputs.

Electrical Performance and Environmental Standards of Infineon FM31256-GTR

In terms of electrical requirements, the FM31256-GTR operates over a wide supply range (2.7V to 5.5V), with industrial temperature compatibility (−40°C to +85°C). Low standby and active currents (150 µA standby, 1.5 mA active at 1 MHz) support energy-efficient designs. The device is fully RoHS3 compliant and offers a moisture sensitivity level of 3 (168 hours), with unaffected REACH status and global regulatory suitability. The robust 14-SOIC package simplifies assembly in standard surface-mount processes.

Alternative and Replacement Options for Infineon FM31256-GTR

For engineers and procurement professionals evaluating alternatives, potential replacements with similar performance include the FM3164 (64-Kbit variant) from the same Infineon (Cypress legacy) family. Both FM3164 and FM31256 share the same feature set—processor companion functions, F-RAM technology, RTC capabilities—but differ in memory density. When selecting a model, the primary consideration is required memory capacity; otherwise, pinout, supervisory, and integration features remain identical. For comparison beyond the Infineon portfolio, consider devices with F-RAM-based processor companion functions and similar RTC/event counter integration, reviewing trade-offs in write endurance, calendar accuracy, and supervisory configurability.

Conclusion

The Infineon FM31256-GTR stands out as a versatile, highly-integrated solution for embedded system designers who require dense nonvolatile memory, long-life real-time clock, and extended processor supervision features. Its consolidation of memory, timekeeping, and system monitoring in one device offers significant value by reducing component count, saving PCB space, and simplifying both hardware and software design flows. Further, the FM31256-GTR’s proven F-RAM endurance and flexible companion functions position it as the preferred choice for applications with stringent reliability, security, or lifecycle requirements. When selecting processor companion ICs, engineers are encouraged to benchmark the FM31256-GTR against both its FM3164 sibling and other market alternatives to ensure optimal system integration and future-proof design.