Infineon Technologies STK16C88-3WF35

Overview

STK16C88-3WF35 from Cypress Semiconductor is a 256 Kbit (32K × 8) nonvolatile SRAM with AutoStore+ functionality, integrating QuantumTrap nonvolatile storage per cell. It operates at 3.3 V ±0.3 V, delivers 35 ns read access time, supports automatic STORE on power loss and RECALL on power-up, and is housed in a 28-pin PDIP package for industrial temperature range (–40°C to +85°C). It replaces battery-backed SRAM modules in mission-critical data logging systems.

For engineers reviewing the STK16C88-3WF35 datasheet, STK16C88-3WF35 pinout, STK16C88-3WF35 application, or STK16C88-3WF35 equivalent, key selection criteria include guaranteed 100-year data retention, 1,000,000 STORE cycles, software-controlled STORE/RECALL via six-address sequence, hardware protection during low-voltage conditions, and compatibility with legacy 28-pin DIP socketed designs requiring zero-battery reliability.

Technical Context

The STK16C88-3WF35 implements a dual-mode nvSRAM architecture: volatile SRAM array (32K × 8) co-located with per-cell QuantumTrap nonvolatile elements. STORE and RECALL operations are triggered either autonomously (hardware) or via deterministic CE-controlled READ sequences to six fixed addresses - no dedicated control pins required.

Hardware STORE initiates within <500 ns when V_CC drops below V_SWITCH, powered by an internal capacitor; hardware RECALL activates on V_CC rise above V_SWITCH with t_HRECALL timing. Software STORE/RECALL disable I/O until completion and require strict address sequencing without intervening accesses - ensuring deterministic, non-disruptive nonvolatile state management.

Key Specifications

Pinout & Package

28-pin Plastic Dual In-line Package (PDIP), 600 mil width, RoHS-compliant. Pin 1 marked by notch or dot; pin numbering follows standard counter-clockwise layout from top-left corner.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STK16C88-3JF35 and DS1248W-120, the STK16C88-3WF35 uniquely combines through-hole serviceability, zero-battery reliability, and deterministic sub-microsecond STORE latency - making it optimal for industrial field equipment where repairability and 100-year data retention are mandatory.

Availability

STK16C88-3WF35 is available at Aetrix Electronics and suitable for industrial programmable logic controllers, smart electricity meters, railway signaling units, and medical diagnostic loggers requiring stable component supply and long-term lifecycle support.

Supply support for STK16C88-3WF35 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 global leader in high-performance memory and mixed-signal ICs, headquartered in San Jose, CA.

The STK16C88 series belongs to Cypress's AutoStore+ nvSRAM product line, engineered specifically to eliminate batteries in mission-critical industrial and infrastructure systems while maintaining pin-and-cycle compatibility with legacy SRAM modules.

FAQ

What triggers automatic STORE on the STK16C88-3WF35?

Automatic STORE initiates when V_CC drops below V_SWITCH (typically ~2.5 V), detected by internal voltage sensing. The operation completes within 500 ns using energy stored in an integrated capacitor - no external components or firmware intervention required. STORE is inhibited unless at least one write has occurred since the last STORE or RECALL cycle, preventing unnecessary wear.

Can software STORE and RECALL be executed concurrently with normal SRAM access?

No. During software STORE or RECALL, all I/O pins are disabled and the device enters a locked state until the full t_STORE or t_RECALL timing completes. The six-address sequence must execute consecutively under CE control with no intervening reads or writes; any interruption aborts the operation. Normal SRAM access resumes only after completion.

Is the STK16C88-3WF35 compatible with 5 V systems?

No. The STK16C88-3WF35 is strictly a 3.3 V device with absolute maximum V_CC rating of 4.5 V. Its DC characteristics and timing are specified over 3.0 V to 3.6 V. Interfacing with 5 V buses requires level-shifting circuitry on address, data, and control lines - direct connection risks permanent damage and violates Absolute Maximum Ratings.

Why does the datasheet state "Not recommended for new designs"?

This designation reflects Cypress's product lifecycle policy: the STK16C88-3WF35 remains in active production solely to support ongoing manufacturing programs with established qualification and certification. It is not promoted for green-field designs due to newer nvSRAM families offering higher densities or lower power, but its proven reliability, 100-year retention, and PDIP form factor retain strong value in maintenance and legacy upgrade contexts.