Infineon Technologies STK14C88-5C35M

Overview

STK14C88-5C35M from Cypress Semiconductor is a 32K × 8 (256 Kb) nonvolatile static RAM with integrated Quantum Trap storage, delivering 35 ns read/write cycle time, automatic STORE on power loss, and automatic RECALL at power-up. It operates from a single 5V ±10% supply, supports commercial temperature range (0°C to 70°C), and uses a 32-pin 300-mil SOIC package - deployed in industrial control data logging where persistent memory retention without backup battery is required.

For engineers reviewing the STK14C88-5C35M datasheet, STK14C88-5C35M pinout, STK14C88-5C35M application, or STK14C88-5C35M equivalent, key selection criteria include AutoStore timing (10 ms STORE duration), HSB-controlled hardware STORE initiation, VCAP capacitor interface for energy hold-up, and compatibility with standard SRAM bus protocols while preserving data across uncontrolled power cycles.

Technical Context

The STK14C88-5C35M integrates volatile SRAM and nonvolatile Quantum Trap cells monolithically per bit, enabling atomic STORE/RECALL operations without external controllers. Its dual-mode operation supports both hardware-triggered STORE (via HSB low pulse) and software-controlled STORE/RECALL via address/command sequences.

Power-loss detection is handled internally through VCAP monitoring; when VCC drops below threshold, the device autonomously initiates STORE using charge stored in the external VCAP capacitor. RECALL occurs fully automatically on VCC ramp-up, restoring full 32K×8 contents into SRAM within microseconds before bus access is enabled.

Key Specifications

Pinout & Package

Package: 32-pin 300-mil SOIC (RoHS-compliant), surface-mount, JEDEC MS-012AC variant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STK14C88-5C35M, STK14CA8-35I offers broader thermal tolerance in a through-hole package, while AS4C32M8D1A-35BCN trades monolithic simplicity for higher bandwidth at the cost of external STORE control and reduced reliability margin in uncontrolled power environments.

Availability

STK14C88-5C35M is available at Aetrix Electronics and suitable for industrial data loggers, point-of-sale terminals, medical infusion pumps, and programmable logic controllers requiring stable component supply and guaranteed long-term data retention without battery support.

Supply support for STK14C88-5C35M 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 STK14C88 belongs to Cypress's nvSRAM product line, engineered specifically to replace battery-backed SRAM in mission-critical systems where maintenance-free, zero-battery nonvolatility is mandatory.

FAQ

What is the role of the VCAP pin and what capacitor value is required?

The VCAP pin connects to an external capacitor that supplies energy during power loss to complete the 10 ms STORE operation. Cypress specifies a minimum 4.7 µF tantalum or low-ESR ceramic capacitor rated for ≥5.5V. Capacitance must be placed within 10 mm of VCAP/VSS pins with low-inductance layout to ensure reliable STORE under worst-case droop conditions.

Can STK14C88-5C35M be used as a direct replacement for standard 32K×8 SRAMs?

Yes - it is pin- and function-compatible with industry-standard 32K×8 SRAMs such as IS61LV256AL, supporting identical address/data/control timing (35 ns). However, VCAP must be added and HSB monitored if hardware STORE is used; otherwise, it behaves identically during normal SRAM operation.

How does AutoStore differ from software-controlled STORE?

AutoStore triggers automatically when VCC falls below threshold, using VCAP energy - no CPU involvement needed. Software STORE requires executing a specific address sequence (e.g., writing to 0xXXXX) and is initiated synchronously with firmware control, allowing precise save points before known resets or updates.

Is the STK14C88-5C35M recommended for new designs?

No - Cypress explicitly marks this device as "Not Recommended for New Designs" in its datasheet (Rev. *B, Dec 2009). While fully functional and supported for legacy repair and continuity, Infineon recommends migrating to newer nvSRAM families like the CY14B108N for enhanced reliability, RoHS-2 compliance, and extended lifecycle support.