Infineon Technologies FM25CL64B-DGTR

Overview

FM25CL64B-DGTR from Infineon Technologies (formerly Cypress) is a 64-Kbit serial SPI F-RAM organized as 8K × 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 functions as a hardware drop-in replacement for serial EEPROM and flash in industrial data logging systems.

For engineers reviewing the FM25CL64B-DGTR datasheet, FM25CL64B-DGTR pinout, FM25CL64B-DGTR application, or FM25CL64B-DGTR equivalent, key selection criteria include write-cycle speed without polling, industrial temperature range (–40 °C to +85 °C), VDD compatibility (2.7–3.65 V), and dual-package availability (SOIC-8 / DFN-8).

Technical Context

The FM25CL64B-DGTR implements ferroelectric memory array architecture with zero-latency write execution - each byte is committed immediately upon successful SPI transfer, eliminating status polling. Its internal logic includes dedicated instruction decoder, address counter, and nonvolatile status register with WPEN control.

It operates as an SPI slave supporting full-duplex mode 0 (CPOL=0, CPHA=0) and mode 3 (CPOL=1, CPHA=1), with SCK edge-triggered timing: SI sampled on rising edge, SO driven on falling edge. The HOLD pin enables transaction suspension without clock or CS dependency, provided transitions occur while SCK is LOW.

Key Specifications

Pinout & Package

FM25CL64B-DGTR is supplied in an 8-pin DFN package (3 mm × 2 mm, 0.5 mm pitch) with exposed pad (NC). Pin functions are electrically identical to the SOIC-8 variant; the DFN variant offers improved thermal performance and board space efficiency.

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-DGTR uniquely delivers simultaneous high endurance, zero-write-latency, and ultra-low standby current - making it optimal for systems requiring both frequent writes and decades-long data integrity without refresh.

Availability

FM25CL64B-DGTR is available at Aetrix Electronics and suitable for industrial data loggers, smart energy meters, PLC I/O modules, and medical diagnostic devices requiring stable component supply across extended product lifecycles.

Supply support for FM25CL64B-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, delivering power management, sensing, connectivity, and security solutions for industrial, automotive, and IoT applications.

The FM25CL64B-DGTR belongs to Infineon's F-RAM portfolio, designed specifically to replace serial EEPROM and flash in applications demanding rapid, reliable, and low-power nonvolatile storage without endurance or latency constraints.

FAQ

Is FM25CL64B-DGTR pin-compatible with standard SPI EEPROMs like AT25xxx series?

Yes - FM25CL64B-DGTR uses identical 8-pin SOIC and DFN footprints and matches the SPI command set (WREN, WRDI, RDSR, WRSR, READ, WRITE) of industry-standard serial EEPROMs. Addressing, opcode structure, and timing parameters align to enable direct hardware substitution without PCB redesign.

Does FM25CL64B-DGTR require special PCB layout considerations compared to EEPROM?

Yes - due to its fast 20 MHz SPI interface and sensitivity to noise-induced false writes, the FM25CL64B-DGTR requires tight SI/SO routing, ground plane under the DFN exposed pad (even though NC), and 100 nF ceramic decoupling placed ≤2 mm from VDD/VSS pins. Avoid shared traces with switching regulators.

Can the HOLD pin be left unconnected in a simple microcontroller design?

No - the HOLD pin must be tied to VDD if unused, as specified in the datasheet. Leaving it floating may cause spurious hold activation due to noise, resulting in stalled SPI transactions and communication timeouts. A 10 kΩ pull-up resistor to VDD satisfies this requirement reliably.

What happens during power-up if CS is asserted before VDD stabilizes?

If CS is driven LOW before VDD reaches 2.7 V, the FM25CL64B-DGTR may enter undefined state or respond unpredictably to opcodes. The internal power-on reset circuit requires VDD ≥2.7 V before accepting commands. Always ensure power sequencing: VDD stable → then assert CS, or use a reset supervisor to gate CS until power is valid.