Infineon Technologies FM25CL64B-DG

Overview

FM25CL64B-DG from Infineon Technologies (formerly Cypress) is a 64-Kbit serial SPI F-RAM organized as 8K × 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 is rated for –40 °C to +85 °C industrial temperature range - deployed in real-time data logging and industrial control systems where rapid, high-endurance writes are critical.

For engineers reviewing the FM25CL64B-DG datasheet, FM25CL64B-DG pinout, FM25CL64B-DG application, or FM25CL64B-DG equivalent, key selection criteria include NoDelay™ write capability, 10¹⁴ endurance cycles, 151-year data retention, low-voltage operation (2.7–3.65 V), and drop-in compatibility with serial EEPROM/flash in SPI-based embedded memory interfaces.

Technical Context

The FM25CL64B-DG implements ferroelectric memory technology to eliminate write latency: each byte is committed immediately upon SPI transfer completion, requiring no polling or delay cycles. Its internal architecture includes an 8K × 8 F-RAM array, 3-bit status register with WPEN control, and dedicated hardware logic for HOLD suspension and CS-activated SPI transaction framing.

It functions strictly as an SPI slave device synchronized to SCK rising edges for input sampling and falling edges for output driving. The 13-bit address space (with upper 3 bits ignored) enables deterministic 2-byte addressing, while the dual-package support (SOIC-8 and DFN-8) maintains identical pin mapping and electrical behavior across form factors.

Key Specifications

Pinout & Package

FM25CL64B-DG 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 (not connected). Both share identical pin numbering and signal assignment.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MB85RS64V and AT25DF041A, FM25CL64B-DG uniquely delivers simultaneous 20 MHz SPI operation, SPI Mode 0/3 flexibility, 10¹⁴ endurance, and true zero-delay writes - making it the only choice for real-time, power-interrupt-resilient data capture in industrial and medical edge devices.

Availability

FM25CL64B-DG is available at Aetrix Electronics and suitable for industrial data loggers, smart meter firmware storage, PLC I/O module configuration, and medical diagnostic device event logs requiring stable component supply across multi-year production cycles.

Supply support for FM25CL64B-DG 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 memory solutions for industrial, automotive, and IoT applications.

The FM25CL64B-DG belongs to Infineon's F-RAM product line, engineered specifically to replace serial EEPROM and flash in applications demanding unlimited write endurance, instant writes, and long-term data retention without power backup.

FAQ

Is FM25CL64B-DG pin-compatible with standard SPI EEPROMs like AT25XXX series?

Yes - FM25CL64B-DG uses the same 8-pin SOIC/DFN footprint and identical SPI pin assignments (CS, SCK, SI, SO, WP, HOLD, VSS, VDD) as industry-standard serial EEPROMs. Opcode structure is also aligned: WREN, WRITE, READ, RDSR, and WRSR commands match functional equivalents, enabling direct hardware substitution without PCB redesign.

Does FM25CL64B-DG require external circuitry for write protection?

No - it integrates three-tiered write protection: hardware via the WP pin (active-low lock for status register), software via WRDI instruction (disables write latch), and configurable block protection (1/4, 1/2, or full array) controlled by status register bits BP0/BP1. No external resistors or logic gates are needed.

What is the maximum sustained write throughput achievable with FM25CL64B-DG?

At 20 MHz SPI clock with continuous byte writes, FM25CL64B-DG achieves 2.5 MB/s effective write throughput (20 Mbps ÷ 8 bits/byte). Because writes incur no delay, this rate is sustainable across the full 8K address space - unlike flash or EEPROM, which degrade with erase-cycle overhead and wear leveling.

Can FM25CL64B-DG operate reliably at 2.5 V supply?

No - its absolute minimum VDD is 2.7 V per datasheet specifications. Operation below 2.7 V risks incomplete write commits, status register corruption, or undefined behavior during power transitions. Designs requiring 2.5 V operation must select alternate F-RAMs such as Cypress's FM24CL64 (2.0–3.6 V range).