Infineon Technologies CY14B256KA-SP45XI

Overview

CY14B256KA-SP45XI from Infineon Technologies (formerly Cypress) is a 256-Kbit (32 K × 8) nonvolatile SRAM with integrated real-time clock, delivering 45 ns access time, infinite SRAM read/write cycles, and 1 million STORE cycles to QuantumTrap nonvolatile elements. It operates at 3.0 V ±10% over industrial temperature range and integrates RTC with alarm, watchdog timer, and capacitor-backed timekeeping - deployed in industrial PLCs for deterministic data logging during brownout events.

For engineers reviewing the CY14B256KA-SP45XI datasheet, CY14B256KA-SP45XI pinout, CY14B256KA-SP45XI application, or CY14B256KA-SP45XI equivalent, key selection criteria include AutoStore timing under VCAP discharge, RTC interrupt latency on INT pin, software STORE address sequence compliance, and compatibility with 48-pin SSOP footprint in space-constrained control modules.

Technical Context

The device embeds parallel SRAM and QuantumTrap nonvolatile storage in a monolithic die, enabling simultaneous SRAM access and background STORE/RECALL with hardware arbitration via HSB pin. Its RTC subsystem includes leap-year tracking, programmable oscillator calibration, and dual backup paths (VCAP or VRTCbat).

AutoStore activation is voltage-triggered at VSWITCH threshold, using charge stored on external VCAP capacitor; STORE execution requires ≥1 prior SRAM write since last RECALL. The INT pin supports configurable active-HIGH push-pull or active-LOW open-drain assertion for alarm, watchdog, or power-monitor events.

Key Specifications

Pinout & Package

48-pin shrink small-outline package (SSOP), RoHS-compliant, with 0.5 mm pitch and exposed pad not present. Pin layout optimized for signal integrity in mixed-signal industrial PCBs, with dedicated VCC/VSS pairs and separated RTC analog supply pins (VRTCcap, VRTCbat).

Key Features

Applications

Equivalent & Alternatives

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

Compared with STK14CA8-350I5F and FM32025-SG, CY14B256KA-SP45XI uniquely combines capacitor-backed hands-off AutoStore, 20-year retention, and 45 ns SRAM speed - making it optimal for industrial designs requiring zero-battery, zero-maintenance, and deterministic power-loss response.

Availability

CY14B256KA-SP45XI is available at Aetrix Electronics and suitable for industrial PLCs, smart utility meters, medical diagnostic devices, and railway signaling controllers requiring stable component supply with guaranteed 20-year data retention and capacitor-based power-loss resilience.

Supply support for CY14B256KA-SP45XI 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

Infineon Technologies is a global semiconductor leader headquartered in Munich, Germany, specializing in power management, sensing, connectivity, and security solutions for industrial, automotive, and IoT applications.

CY14B256KA belongs to Infineon's legacy Cypress nvSRAM product line, engineered specifically for mission-critical industrial systems demanding zero-data-loss memory persistence and integrated timekeeping without batteries or external supervisors.

FAQ

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

The CY14B256KA-SP45XI requires a minimum 0.1 µF ceramic capacitor on the VCAP pin, rated for ≥10 V, placed within 5 mm of the package per datasheet Figure 2. This value ensures sufficient charge to complete a full STORE cycle when VCC drops below VSWITCH (typically 2.5 V). Larger capacitors extend margin but do not improve STORE speed.

Can the RTC operate independently while the nvSRAM is in deep sleep?

Yes - the RTC continues running from VRTCcap or VRTCbat backup power even when VCC is removed or held at 0 V. The nvSRAM core is powered down, but RTC registers remain accessible via DQ0–DQ7, and INT asserts on alarm or watchdog timeout. No SRAM access is possible until VCC is restored and RECALL completes.

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

During software STORE, HSB is driven LOW by internal logic for the duration of the STORE operation (typ. 10–15 ms), then released HIGH. Unlike hardware STORE, no initial tHHHD pulse occurs. The pin remains functional as status indicator only - it cannot be used to initiate software STORE, which requires a specific address write sequence to 0x0000–0x000F.

Is the CY14B256KA-SP45XI compatible with standard SRAM timing protocols?

Yes - it fully complies with JEDEC-standard asynchronous SRAM timing: CE/OE-controlled read cycles, WE-controlled writes, and tAA/tHZWE/tSD timing parameters match industry norms. No special controller logic is needed beyond standard 32K×8 SRAM interface, though AutoStore and RTC registers require extended address decoding above 0x8000.