Infineon Technologies FM25040B-GTR

Overview

FM25040B-GTR from Infineon Technologies (formerly Cypress) is a 4-Kbit serial SPI F-RAM organized as 512 × 8, featuring NoDelay™ writes, 10¹⁴ read/write endurance, and 151-year data retention. It operates at up to 20 MHz SPI clock, supports modes 0 and 3, and is housed in an 8-pin SOIC package for industrial-temperature (–40 °C to +85 °C) embedded nonvolatile memory applications including metering data logging and real-time event capture.

For engineers reviewing the FM25040B-GTR datasheet, FM25040B-GTR pinout, FM25040B-GTR application, or FM25040B-GTR equivalent, key selection criteria include write-cycle speed without polling, hardware/software write protection granularity (1/4, 1/2, or full array), VDD range (4.5–5.5 V), standby current (4 µA typ), and SPI bus compatibility with legacy EEPROM/flash footprints.

Technical Context

The FM25040B-GTR implements ferroelectric memory cells enabling true byte-write capability at SPI bus speed-no internal write cycle delay or status polling required. Its control logic integrates opcode decoding, address counter, and dual-mode SPI interface (0 and 3), with dedicated hardware write protection via WP pin and software-configurable block lock in the nonvolatile status register.

Unlike flash or EEPROM, it eliminates erase-before-write overhead and achieves 100 trillion write cycles by avoiding charge-trapping mechanisms. The 9-bit addressing scheme (512 × 8) maps directly to SPI opcodes and 8-bit word addresses, with all timing governed solely by SCK edges-data is latched on rising SCK and output on falling SCK.

Key Specifications

Pinout & Package

FM25040B-GTR is supplied in an 8-pin Small Outline Integrated Circuit (SOIC) package with standard 150-mil width and gull-wing leads, RoHS-compliant and optimized for reflow soldering in high-volume PCB assembly.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar serial nonvolatile memory applications.

Compared with AT25DF041A-SSH-T and BR24G04FJ-WE2, FM25040B-GTR uniquely delivers bus-speed writes, 100× higher endurance than EEPROM, and 3.8× longer retention than flash-making it the sole choice for mission-critical, high-write industrial data buffers.

Availability

FM25040B-GTR is available at Aetrix Electronics and suitable for smart metering, industrial PLCs, medical diagnostics, and automotive body control modules requiring stable component supply, long-life data integrity, and zero-latency nonvolatile writes.

Supply support for FM25040B-GTR 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, delivering power management, sensing, connectivity, and security solutions for industrial, automotive, and IoT markets.

The FM25040B-GTR belongs to Infineon's F-RAM product line-engineered specifically to replace serial EEPROM and flash in applications demanding extreme write endurance, instant writes, and guaranteed data retention across extended temperature and time horizons.

FAQ

Is FM25040B-GTR pin-compatible with standard SPI EEPROMs like the 25AA040A?

Yes-FM25040B-GTR uses identical 8-pin SOIC packaging and matches the pin functions of industry-standard 4-Kbit SPI EEPROMs (CS, SCK, SI, SO, WP, HOLD, VSS, VDD). No PCB redesign is needed for drop-in replacement, though firmware must disable EEPROM-specific polling routines due to NoDelay™ writes.

Does FM25040B-GTR require external circuitry for write protection?

No-write protection is fully integrated: hardware lock via the WP pin and software-configurable block protection (1/4, 1/2, or full array) controlled through the nonvolatile status register. External resistors or logic gates are unnecessary unless custom system-level locking is required.

What is the impact of the documented errata regarding WEL bit behavior at addresses 0x100–0x1FF?

The WEL (Write Enable Latch) bit remains set after writes to memory locations 0x100–0x1FF, requiring explicit WRDI instruction before subsequent writes to those addresses. This does not affect reliability or data integrity-it only mandates minor firmware adjustment to issue WRDI before each write sequence targeting that block.

Can FM25040B-GTR operate reliably at 20 MHz across the full industrial temperature range?

Yes-the 20 MHz maximum SPI clock is fully specified and tested from –40 °C to +85 °C per AC switching characteristics in Rev. *K datasheet. Setup/hold times and propagation delays remain within margin at both extremes, provided VDD stays within 4.5–5.5 V and PCB layout follows SPI signal integrity guidelines.