Infineon Technologies FM25L04B-G

Overview

FM25L04B-G from Infineon Technologies (formerly Cypress) is a 4-Kbit serial SPI F-RAM organized as 512 × 8, delivering true RAM-like write performance with nonvolatile data retention. It operates at up to 20 MHz SPI clock, supports SPI modes 0 and 3, features hardware/software write protection, and guarantees 10¹⁴ read/write cycles with 151-year data retention over –40 °C to +85 °C - ideal for high-frequency logging in industrial sensor nodes.

For engineers reviewing the FM25L04B-G datasheet, FM25L04B-G pinout, FM25L04B-G application, or FM25L04B-G equivalent, key selection criteria include NoDelay™ write capability, absence of write polling, endurance vs. serial EEPROM/flash, and compatibility with existing SPI memory interfaces requiring zero-latency writes and low-power operation.

Technical Context

The FM25L04B-G implements a ferroelectric memory array with direct byte-addressable access via standard SPI protocol, eliminating erase-before-write and internal timing delays. Its status register includes WEL and block protection bits, and the HOLD pin enables transaction suspension without clock or CS dependency.

It uses no internal charge pumps or high-voltage generators - enabling 2.7–3.6 V operation, 200 µA active current at 1 MHz, and 3 µA typical standby current. The device requires no power-on reset circuitry beyond its internal POR, and all write operations complete within one SPI frame.

Key Specifications

Pinout & Package

FM25L04B-G is available in two RoHS-compliant packages: 8-pin SOIC (3.9 mm × 4.9 mm) and 8-pin DFN (2 mm × 3 mm) with exposed pad (unconnected). Both packages share identical pin functions and ordering code suffix "-G" denotes green/lead-free compliance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT25SF041 and BR24G04FJ, FM25L04B-G delivers 10⁸× higher endurance, 50× faster effective write throughput, and deterministic latency - making it uniquely suited for applications demanding frequent, low-overhead nonvolatile updates without firmware complexity.

Availability

FM25L04B-G is available at Aetrix Electronics and suitable for smart metering, industrial PLC configuration, and medical sensor calibration requiring stable component supply, long-lifecycle support, and guaranteed RoHS-compliant manufacturing.

Supply support for FM25L04B-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 systems, sensors, and secure connectivity solutions for automotive, industrial, and IoT markets.

The FM25L04B-G belongs to Infineon's F-RAM product line, engineered specifically to replace serial EEPROM and flash in applications where write endurance, speed, and reliability outweigh raw density requirements.

FAQ

Is FM25L04B-G pin-compatible with standard SPI EEPROMs like AT25040?

Yes - FM25L04B-G uses identical 8-pin SOIC/DFN footprints and SPI command set (WREN, WRITE, READ, RDSR, WRSR), enabling direct PCB-level replacement. No layout changes or firmware modifications are required beyond disabling EEPROM write polling loops.

Does FM25L04B-G require external high-voltage circuitry for writes?

No - the device uses ferroelectric memory cells that switch polarization at standard 3.3 V supply levels. There are no internal charge pumps, no high-voltage generators, and no voltage boosting circuits - simplifying power design and reducing EMI.

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

The Write Enable Latch (WEL) bit remains set after writes to memory locations 0x100–0x1FF, requiring explicit WRDI instruction before subsequent writes to other pages. This does not affect data integrity but mandates minor firmware adjustment to clear WEL before cross-page operations.

Can the HOLD pin be used to pause a write operation mid-byte?

No - HOLD suspends the SPI transaction only between bytes or opcodes. Once a byte transfer begins (i.e., first SCK edge after CS low), it completes fully before HOLD takes effect. This ensures atomicity of each byte-level memory access.