Infineon Technologies FM31276-G

Overview

FM31276-G from Infineon Technologies (formerly Cypress) is a 64-Kbit integrated processor companion IC combining ferroelectric RAM (F-RAM), real-time clock (RTC), low-VDD supervisor, watchdog timer, dual event counter, and 64-bit lockable serial number in a single 14-pin SOIC package. It delivers 10¹⁴ read/write endurance, 151-year data retention, and I²C interface up to 1 MHz - deployed in industrial metering, medical data loggers, and battery-backed control systems requiring deterministic nonvolatile storage and timekeeping.

For engineers reviewing the FM31276-G datasheet, FM31276-G pinout, FM31276-G application, or FM31276-G equivalent, key selection criteria include F-RAM write endurance vs. EEPROM, RTC BCD calendar with leap-year support through 2099, programmable VDD reset threshold (2.5 V / 2.7 V / 2.9 V / 3.1 V), battery-backed event counting on CNT1/CNT2, and UL-recognized trickle-charge capability for lithium backup.

Technical Context

The FM31276-G implements a dual-function I²C slave architecture: one device address (0x50–0x53) for 8K × 8 F-RAM memory access, and a separate address (0x68) for RTC/companion register space. All timekeeping and supervisory circuits remain active under VBAK backup power (1.8–3.6 V), enabling continuous operation during main supply loss.

Its supervisor block integrates a voltage monitor with four selectable reset thresholds, a 100 ms–3 s programmable watchdog timer with flag reporting, and a comparator comparing PFI to an internal 1.2 V reference - configurable as early power-fail NMI or general-purpose analog input. The CAL/PFO pin serves dual roles: 512 Hz calibration output or power-fail alert signal.

Key Specifications

Pinout & Package

14-pin Small Outline Integrated Circuit (SOIC), RoHS-compliant, body width 3.9 mm, lead pitch 1.27 mm.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar integrated processor companion applications.

Compared with DS1343E-33+ and PCF2129AT/1,118, FM31276-G reduces component count by integrating memory, RTC, supervisor, counters, and security features - delivering higher reliability in power-critical applications where deterministic write latency and long-term data integrity are mandatory.

Availability

FM31276-G is available at Aetrix Electronics and suitable for industrial energy metering, medical data loggers, smart building controllers, and POS terminal transaction logging requiring stable component supply across extended product lifecycles.

Supply support for FM31276-G includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Infineon Technologies is a global semiconductor leader headquartered in Munich, Germany, specializing in power management, sensing, connectivity, and security solutions for industrial, automotive, and IoT applications.

The FM31276-G belongs to Infineon's legacy Cypress processor companion portfolio, designed specifically to replace discrete RTC, supervisor, and nonvolatile memory ICs in resource-constrained embedded systems demanding high-reliability, low-power, and long-life data retention.

FAQ

What backup power sources are supported on VBAK?

VBAK accepts 1.8 V to 3.6 V backup supplies, including CR2032 coin cells, rechargeable Li-ion/Li-polymer batteries, or supercapacitors. The integrated UL-recognized trickle charger supports constant-current charging of lithium cells up to 10 µA, eliminating need for external charging circuitry. If no backup is used, VBAK must be tied to ground and the VBC bit cleared in RTC register 0Bh.

How does the FM31276-G handle I²C bus contention between memory and RTC registers?

The FM31276-G uses two independent I²C slave addresses: 0x50–0x53 for F-RAM access and 0x68 for RTC/companion registers. This separation allows concurrent memory reads and RTC time queries without address collision or bus arbitration conflicts. Memory operations continue uninterrupted during RTC register access, preserving real-time logging integrity.

Can the event counters operate without main power (VDD)?

Yes - CNT1 and CNT2 are fully battery-backed via VBAK. When VDD drops below operating range, the counters continue incrementing on detected edges as long as VBAK remains ≥1.8 V. Their values persist across power cycles and are readable via I²C after VDD restoration, making them ideal for tamper detection or maintenance cycle tracking in unattended equipment.

Is the 64-bit serial number truly one-time programmable and irreversible?

Yes - the 64-bit serial number region is protected by a dedicated hardware lock bit (SNL in register 0Bh). Once set, the lock bit cannot be cleared, and subsequent writes to the serial number registers are ignored. This provides cryptographic-grade uniqueness and prevents reprogramming or cloning, satisfying requirements for firmware authentication and device identity binding in regulated environments.