Infineon Technologies STK14D88-RF25

Overview

STK14D88-RF25 from Cypress Semiconductor is a 32K × 8 (256 Kb) nonvolatile static RAM with integrated Quantum Trap storage, delivering 25 ns read access time, automatic STORE on power loss, and automatic RECALL at power-up. It operates from a single 3.0V ±10% supply, supports industrial temperature range (–40°C to +85°C), and uses a 48-pin SSOP package. It serves as a drop-in SRAM replacement in systems requiring guaranteed data retention during unexpected power failure - e.g., industrial PLCs, metering, and network control cards.

For engineers reviewing the STK14D88-RF25 datasheet, STK14D88-RF25 pinout, STK14D88-RF25 application, or STK14D88-RF25 equivalent, key selection criteria include AutoStore timing (12.5 ms), VCAP capacitor requirement (17–120 µF), HSB hardware store signaling, unlimited SRAM endurance, and 20-year nonvolatile data retention at 55°C.

Technical Context

The STK14D88-RF25 integrates SRAM and nonvolatile Quantum Trap cells monolithically, enabling atomic STORE/RECALL without external controllers. Its STORE operation triggers automatically when VCC drops below 2.65 V or via HSB assertion, completing within 12.5 ms (industrial max 15 ms). RECALL initiates at power-up once VCC exceeds 2.65 V and completes within 20 ms.

It supports standard parallel SRAM interface timing: 25 ns read/write cycle time, 12 ns output enable delay, and tri-state outputs controlled by E and G. The device requires an external VCAP capacitor (17–120 µF, 5 V rated) connected between VCAP and VSS to sustain STORE during brownout.

Key Specifications

Pinout & Package

STK14D88-RF25 is housed in a 48-pin SSOP (RF package), RoHS-compliant, with 0.635 mm pitch and 12.8 mm × 7.5 mm footprint. Pinout supports standard parallel memory interface with dedicated STORE/RECALL control signals.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STK14C88-RF25, the STK14D88-RF25 delivers 10 ns faster access for tighter timing margins; compared with FM24CL64-G, it retains pin-compatible SRAM interface and deterministic STORE latency but requires VCAP support and consumes higher standby current.

Availability

STK14D88-RF25 is available at Aetrix Electronics and suitable for industrial programmable logic controllers, smart electricity meters, and telecom line cards requiring stable component supply, long-lifecycle assurance, and guaranteed nonvolatile data integrity without batteries.

Supply support for STK14D88-RF25 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

Cypress Semiconductor (now part of Infineon Technologies) designs high-reliability memory and programmable solutions for industrial, automotive, and communications markets.

The STK14D88 belongs to Cypress's nvSRAM product line, engineered specifically to replace battery-backed SRAM in mission-critical systems where maintenance-free, long-term data retention is mandatory.

FAQ

Is STK14D88-RF25 pin-compatible with standard 32K×8 SRAMs?

Yes - it uses identical 48-pin SSOP pinout and standard parallel interface signals (A0–A14, DQ0–DQ7, E, W, G). No PCB redesign is needed beyond adding the VCAP capacitor and routing HSB if hardware STORE is used. All timing parameters align with JEDEC-standard fast SRAMs.

What capacitor value and rating must be used on the VCAP pin?

A 17–120 µF, 5 V rated tantalum or low-ESR aluminum electrolytic capacitor must be placed between VCAP and VSS. Minimum 17 µF ensures STORE completion under worst-case industrial temperature and voltage conditions; 120 µF provides margin for extended hold-up or aging derating.

Can STORE be disabled to reduce power or extend nonvolatile cycle life?

No - AutoStore cannot be disabled. However, STORE only occurs after a write has taken place since the last RECALL, and only if VCC drops below 2.65 V or HSB is asserted. Frequent writes without intervening RECALL will not trigger repeated STORE unless power loss or explicit command occurs.

Does STK14D88-RF25 support software STORE/RECALL on all operating voltages?

Yes - software-controlled STORE and RECALL commands function across the full VCC range (2.7 V to 3.6 V). However, successful STORE execution requires sufficient VCAP charge; operation near 2.7 V may require larger VCAP values to maintain tSTORE timing margin.