Infineon Technologies STK14CA8-NF45

Overview

STK14CA8-NF45 from Cypress Semiconductor is a 128K × 8 (1 Mb) nonvolatile static RAM with integrated QuantumTrap storage, operating at 3.0V ±10%, delivering 45 ns read/write cycle time, unlimited SRAM read/write endurance, and automatic STORE/RECALL on power loss/power-up. It serves as a drop-in replacement for standard SRAM in systems requiring persistent data retention without external backup power or batteries - e.g., industrial PLCs maintaining configuration during brownouts.

For engineers reviewing the STK14CA8-NF45 datasheet, STK14CA8-NF45 pinout, STK14CA8-NF45 application, or STK14CA8-NF45 equivalent, key selection criteria include AutoStore timing (12.5 ms), VCAP capacitor requirement (17–120 µF), HSB hardware control interface, 20-year data retention at 55°C, and compatibility with standard parallel SRAM bus protocols.

Technical Context

The STK14CA8-NF45 implements monolithic nvSRAM architecture where each memory cell embeds a QuantumTrap nonvolatile element alongside standard SRAM. STORE is triggered automatically when VCC drops below 2.65 V or via HSB pin assertion; RECALL occurs automatically at power-up once VCC exceeds that threshold.

It supports three STORE modes: AutoStore (power-loss detection), Hardware STORE (HSB-driven), and Software STORE (via command sequence). All modes complete within 12.5 ms (industrial grade ≤15 ms), with VCAP supplying hold-up energy during the STORE operation - requiring external 17–120 µF tantalum or polymer capacitor rated ≥5 V.

Key Specifications

Pinout & Package

STK14CA8-NF45 is packaged in a 32-pin SOIC (Small Outline Integrated Circuit) with 0.4-inch body width and standard JEDEC MS-012AC footprint. Pin assignments follow industry-standard parallel SRAM layout with dedicated HSB (Hardware Store Busy), VCAP (AutoStore capacitor connection), and conventional E/W/G control signals.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STK14CA8-RF45, the NF45 offers lower thermal resistance and smaller PCB footprint; versus FM1808-45-SG, it provides hardware-level STORE control and status feedback - essential for safety-critical or tightly timed power-management architectures.

Availability

STK14CA8-NF45 is available at Aetrix Electronics and suitable for industrial PLCs, telecom line cards, medical infusion pumps, and ANSI C12.20 energy meters requiring stable component supply, long-term lifecycle support, and guaranteed nonvolatile data retention without battery dependency.

Supply support for STK14CA8-NF45 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) is a U.S.-based semiconductor company specializing in memory, microcontrollers, and programmable logic solutions for industrial, automotive, and communications markets.

The STK14CA8 belongs to Cypress's nvSRAM product line, designed specifically to replace battery-backed SRAM and EEPROM in mission-critical systems where data persistence, reliability, and zero-maintenance operation are mandatory.

FAQ

What is the function of the VCAP pin, and what capacitor value must be used?

The VCAP pin connects an external capacitor that supplies energy during the AutoStore operation when VCC collapses. The datasheet specifies a range of 17 µF to 120 µF, rated ≥5 V. A 47 µF tantalum or polymer capacitor is commonly used to ensure reliable STORE completion across temperature and voltage droop profiles.

Can STK14CA8-NF45 be used as a direct replacement for standard SRAM without circuit modification?

Yes - electrically and pin-compatible with standard 32-pin SOIC 128K×8 SRAMs. However, VCAP must be populated, and HSB should be pulled up via 10 kΩ resistor if unused. No firmware changes are needed for basic read/write, but leveraging AutoStore requires minimal power-fail detection or HSB monitoring logic.

How does the HSB pin behave during STORE, and what is its role in system design?

HSB goes low during STORE (both AutoStore and hardware-initiated) and returns high upon completion. It serves dual roles: output signal for monitoring STORE progress, and input (when externally pulled low) to trigger STORE. This enables precise coordination with system power controllers or watchdog circuits.

Is STK14CA8-NF45 still recommended for new designs, and what is its obsolescence status?

No - Cypress documentation explicitly marks STK14CA8 as "Not Recommended for New Designs." It remains available for legacy support and production continuity, but Infineon recommends migration to newer nvSRAM families (e.g., CY14B108L) offering enhanced reliability, extended temperature range, and improved STORE timing consistency.