Infineon Technologies STK17T88-RF45

Overview

STK17T88-RF45 from Cypress Semiconductor is a 32K × 8 (256 Kb) nonvolatile SRAM with integrated real-time clock, watchdog timer, alarm, and power monitor. It operates from a single 3.0V ±10% supply, delivers 45 ns read/write cycle time, supports automatic STORE on power loss and RECALL on power-up, and uses a 48-pin SSOP package. It is deployed in industrial control systems requiring persistent time-stamped data logging during brownouts.

For engineers reviewing the STK17T88-RF45 datasheet, STK17T88-RF45 pinout, STK17T88-RF45 application, or STK17T88-RF45 equivalent, key selection criteria include nvSRAM endurance (200K STORE cycles), RTC backup options (capacitor or battery), HSB-controlled hardware STORE, interrupt-driven alarm/wdog response, and compatibility with legacy 3V SRAM bus timing.

Technical Context

The STK17T88 integrates a QuantumTrap-based nvSRAM array (512 × 512) with a fully autonomous RTC subsystem featuring leap-year compensation, programmable oscillator calibration, and dual-interrupt sources (alarm + watchdog). Its power management logic monitors VCC and triggers STORE when voltage drops below threshold, using charge stored on the external VCAP capacitor.

All RTC registers (16 bytes) and SRAM (32,768 bytes) share the same 8-bit bidirectional DQ bus and 15-bit address bus (A0–A14), with separate control lines (E, W, G, HSB, INT) enabling concurrent memory access and timekeeping. The device supports both hardware-initiated (HSB pull-down) and software-initiated STORE/RECALL sequences via dedicated command codes.

Key Specifications

Pinout & Package

STK17T88-RF45 is housed in a 48-pin, 300-mil wide SSOP package (RoHS compliant), with 0.025-inch pitch and exposed thermal pad not connected internally. Pin assignments follow JEDEC MO-153 standards.

Key Features

Applications

Equivalent & Alternatives

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

Compared with STK17TA8-45 and DS1687-5+, the STK17T88-RF45 uniquely supports dual RTC backup (capacitor or battery), fits standard SSOP-48 footprints, and offers lower standby current (3 mA vs. 5 mA typical), making it optimal for compact, battery-sensitive industrial edge nodes.

Availability

STK17T88-RF45 is available at Aetrix Electronics and suitable for industrial control systems, medical data loggers, smart meters, and telecom infrastructure requiring stable component supply and long-term obsolescence support.

Supply support for STK17T88-RF45 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 high-reliability memory, PSoC, and timing solutions for industrial and automotive markets.

The STK17T88 belongs to Cypress's AutoStore nvSRAM product line, engineered to eliminate external EEPROM/NVRAM and battery backup circuitry while delivering deterministic, zero-latency nonvolatile storage for mission-critical time-aware systems.

FAQ

What is the minimum VCAP capacitance required for reliable STORE operation?

The STK17T88-RF45 requires a minimum 17 µF, 5V-rated capacitor between VCAP and VSS to ensure full STORE completion during worst-case VCC dropout (2.7 V → 0 V in ≤100 µs). Typical designs use 33 µF tantalum or polymer capacitors to accommodate aging and temperature derating.

Can the RTC operate independently while the nvSRAM is disabled?

Yes - the RTC continues running from VRTCcap or VRTCbat even when VCC is absent or E is deasserted. The oscillator, calendar, alarm, and watchdog functions remain fully active as long as backup power is present, and RTC registers remain readable via DQ bus upon VCC restoration.

How does the HSB pin behave during a software-initiated STORE?

HSB asserts low during both hardware-triggered and software-initiated STORE operations, providing synchronous status feedback to the host processor. Its duration matches tSTORE (≤10 ms), and it remains high during normal read/write cycles - enabling reliable STORE completion polling without additional timing margins.

Is the STK17T88-RF45 compatible with standard SRAM timing protocols?

Yes - it complies with JEDEC-standard asynchronous SRAM timing: E/W/G control signals, 45 ns tRC and tWC, and tristate DQ bus behavior. No glue logic or timing adaptation is needed when replacing 3V 32K×8 SRAMs, provided HSB is monitored for STORE interference and VCAP is added.