Infineon Technologies FM31L276-G

Overview

FM31L276-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 battery-backed event counters, and 64-bit lockable serial number in a single 14-pin SOIC package. It operates from 2.7 V to 3.6 V, delivers 1.15 µA RTC backup current at 2 V/25 °C, supports 1-MHz I²C interface, and provides 10¹⁴ read/write endurance with 151-year data retention - deployed in industrial metering and embedded control systems requiring high-reliability nonvolatile state storage.

For engineers reviewing the FM31L276-G datasheet, FM31L276-G pinout, FM31L276-G application, or FM31L276-G equivalent, key selection considerations include its F-RAM write-no-wait behavior, programmable reset threshold (VTP), battery-backed RTC/calendar with leap-year support through 2099, dual edge-triggered event counters, and I²C slave address configuration via A0/A1 pins.

Technical Context

The FM31L276-G implements two logically independent I²C devices on one die: an 8K × 8 F-RAM array (slave address 0x50–0x53) and a companion peripheral block (slave address 0x68) housing RTC registers, supervisor control, event counters, and serial number. Its RTC uses a 32.768 kHz crystal (6 pF/12.5 pF load) with software calibration and BCD-coded time/date from seconds to centuries.

Supervision logic includes a programmable low-VDD reset trip point (VTP), 100 ms reset pulse width (tRPU), manual reset debouncing, and a comparator (PFI input vs. internal 1.2 V reference) for early power-fail NMI generation. The RST pin is open-drain with weak pull-up and supports wire-OR reset bus topology.

Key Specifications

Pinout & Package

FM31L276-G is housed in a 14-pin Small Outline Integrated Circuit (SOIC) package with standard 1.27 mm pitch and RoHS-compliant finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS1340Z-33+T&R and MAX31329EKA+T, FM31L276-G uniquely integrates high-endurance F-RAM, programmable supervisor, dual event counters, and lockable serial number - enabling single-chip replacement of discrete RTC, EEPROM, reset IC, and counter IC in industrial control and metering.

Availability

FM31L276-G is available at Aetrix Electronics and suitable for smart metering, industrial PLC controllers, medical diagnostic equipment, and building automation gateways requiring stable component supply, long-life data retention, and robust power-fail resilience.

Supply support for FM31L276-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 automotive, industrial, and IoT applications.

The FM31L276-G belongs to Infineon's legacy Cypress processor companion family, designed specifically to consolidate nonvolatile memory, real-time clock, and system supervision into one reliable, low-power IC for mission-critical embedded systems.

FAQ

What is the maximum I²C clock frequency supported by FM31L276-G?

The FM31L276-G supports I²C operation up to 1 MHz under standard conditions (VDD ≥ 2.7 V, temperature ≤ +85 °C). It maintains backward compatibility with legacy 100 kHz and 400 kHz timings, allowing seamless integration into existing I²C infrastructure without protocol changes.

How does the FM31L276-G handle power transitions between VDD and VBAK?

When VDD drops below the reset threshold (VTP), the RTC, event counters, and serial number remain powered by VBAK, preserving time, counts, and identity. The F-RAM retains data without backup power due to intrinsic nonvolatility. RST remains asserted until VDD rises above VTP and holds for ≥100 ms to guarantee clean system reset.

Can the 64-bit serial number be rewritten after locking?

No. Once the lock bit (bit 7 of RTC register 0Bh) is set, the 64-bit serial number becomes permanently read-only. The lock is irreversible and enforced by hardware - no software command or voltage sequence can unlock or modify the programmed value.

Is external crystal load capacitance configurable for the RTC oscillator?

Yes. The FM31L276-G supports either 6 pF or 12.5 pF crystal load capacitance, selected automatically based on the crystal's specified load value. No external capacitors are required - the internal oscillator circuit configures itself to match the connected 32.768 kHz crystal specification.