Infineon Technologies FM25L04B-DGTR

Overview

FM25L04B-DGTR from Infineon Technologies (formerly Cypress) is a 4-Kbit serial SPI F-RAM organized as 512 × 8, serving as nonvolatile memory with true RAM-like write performance in embedded control and data-logging systems. It delivers 10¹⁴ read/write endurance, 151-year data retention at +85 °C, NoDelay™ writes at up to 20 MHz SPI clock, and operates from 2.7 V to 3.6 V across –40 °C to +85 °C.

For engineers reviewing the FM25L04B-DGTR datasheet, FM25L04B-DGTR pinout, FM25L04B-DGTR application, or FM25L04B-DGTR equivalent, key selection criteria include guaranteed zero-write-latency operation, hardware/software write protection granularity (1/4, 1/2, full array), industrial temperature compliance, and direct SPI flash/EEPROM drop-in replacement capability without firmware changes.

Technical Context

The FM25L04B-DGTR implements a ferroelectric memory array with synchronous SPI slave interface supporting modes 0 (CPOL = 0, CPHA = 0) and 3 (CPOL = 1, CPHA = 1). All write operations complete within one SPI byte transfer cycle-no polling or delay required-and status register updates occur atomically with memory writes.

Its internal architecture includes dedicated instruction decoder, address counter, and nonvolatile status register with WEL bit; the HOLD pin enables deterministic transaction suspension while SCK is low, preserving bus state integrity during host interrupt servicing.

Key Specifications

Pinout & Package

FM25L04B-DGTR is supplied in an 8-pin DFN package (3 mm × 2 mm, 0.5 mm pitch) with exposed pad (not connected). Pin functions are electrically identical to the SOIC variant but optimized for space-constrained PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MB85RS4MT-FPNSE1 and AT25SF041-SSHD-B, FM25L04B-DGTR uniquely delivers sub-microsecond write commit, hardware HOLD support, and 10¹⁴ endurance in a pin-compatible 8-pin DFN-making it the sole option for latency-critical, high-cycle-count industrial logging where flash/EEPROM alternatives introduce firmware complexity or reliability risk.

Availability

FM25L04B-DGTR is available at Aetrix Electronics and suitable for industrial data loggers, smart meter firmware storage, automotive body control modules, and medical diagnostic equipment requiring stable component supply over extended production lifecycles.

Supply support for FM25L04B-DGTR 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 memory solutions for industrial, automotive, and IoT applications.

The FM25L04B-DGTR belongs to Infineon's F-RAM product line, engineered specifically to replace serial flash and EEPROM in applications demanding unlimited write cycles, zero write latency, and long-term data integrity without system-level wear management.

FAQ

Does FM25L04B-DGTR require external pull-up resistors on SI, SO, or HOLD pins?

No. The FM25L04B-DGTR has internal weak pull-ups on HOLD and WP pins only; SI and SO are actively driven and do not require external termination. External pull-ups on SI/SO may cause signal integrity issues or exceed VIH/VIL thresholds under high-speed operation.

Can FM25L04B-DGTR be used as a direct replacement for AT25DF041A without firmware changes?

Yes-FM25L04B-DGTR shares identical pinout, SPI command set (WREN, WRITE, READ, RDSR), and timing structure with AT25DF041A. No code modifications are needed beyond verifying VDD range compatibility (2.7–3.6 V vs. 2.7–3.6 V) and removing EEPROM-style polling loops.

What is the impact of the documented WEL bit errata on memory writes to addresses 0x100–0x1FF?

The WEL bit remains set after writes to 0x100–0x1FF, requiring explicit WRDI before subsequent writes to other pages. This does not corrupt data but mandates strict status register management in firmware-unlike normal operation where WEL auto-clears post-write.

Is the exposed pad on the DFN package electrically connected or thermally functional?

The exposed pad on FM25L04B-DGTR's DFN package is a no-connect terminal-not bonded to die or substrate. It must remain unsoldered per datasheet guidance to prevent mechanical stress or unintended grounding paths that could compromise ESD robustness.