Infineon Technologies CY14B256PA-SFXI

Overview

CY14B256PA-SFXI from Cypress Semiconductor is a 256-Kbit (32 K × 8) SPI nonvolatile SRAM with integrated real-time clock, AutoStore/RECALL functionality, and 40 MHz/104 MHz dual-speed SPI interface. It uses QuantumTrap nonvolatile technology for 20-year data retention at 85 °C, supports hardware STORE via HSB pin, and delivers 0.45 µA RTC backup current with programmable square-wave output (1 Hz to 32.768 kHz). Used in industrial logging systems requiring power-loss-resilient time-stamped memory.

For engineers reviewing the CY14B256PA-SFXI datasheet, CY14B256PA-SFXI pinout, CY14B256PA-SFXI application, or CY14B256PA-SFXI equivalent, key selection criteria include VCC range (2.7–3.6 V), SOIC-16 package compatibility, RTC alarm interrupt capability, SPI mode 0/3 support, and hardware STORE timing under capacitor-backed power-down.

Technical Context

This nvSRAM integrates SRAM and QuantumTrap nonvolatile storage on a single die, enabling infinite SRAM write cycles while limiting STORE endurance to 1 million cycles. The RTC subsystem includes independent counters, alarm registers, watchdog timer, and programmable INT/SQW output with selectable polarity and frequency modes.

Power management is split across three domains: main VCC (2.7–3.6 V), RTC backup (VCAP or VRTCbat), and AutoStore capacitor supply (VCAP). STORE triggers automatically on VCC drop below threshold or via SPI instruction/HSB assertion; RECALL occurs at power-up or via SPI command - both operations block memory access until completion.

Key Specifications

Pinout & Package

16-pin Small Outline Integrated Circuit (SOIC), 300-mil body width, RoHS-compliant, surface-mount package with standard JEDEC MS-012AC footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with FM31L278-G and RV-3032-C3, CY14B256PA-SFXI uniquely combines deterministic hardware STORE triggering, integrated recall automation, and multi-frequency square-wave generation - making it optimal for systems where power-loss response must be guaranteed without host CPU involvement.

Availability

CY14B256PA-SFXI is available at Aetrix Electronics and suitable for industrial data loggers, smart metering endpoints, medical diagnostic recorders, and PLC I/O modules requiring stable component supply with long-term lifecycle assurance.

Supply support for CY14B256PA-SFXI 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, acquired by Infineon Technologies in 2020, designs high-reliability mixed-signal ICs for industrial, automotive, and IoT applications with emphasis on nonvolatile memory and timing solutions.

CY14B256PA belongs to the nvSRAM+RTC product line engineered for systems demanding deterministic data preservation during uncontrolled power loss - targeting applications where EEPROM write latency or battery-backed RAM maintenance is unacceptable.

FAQ

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

The datasheet specifies a minimum 47 µF tantalum or ceramic capacitor on VCAP for guaranteed STORE completion during VCC dropout. At 3.3 V supply and 2.7 V VCC threshold, this provides ≥20 ms hold-up time - sufficient for full 32 K × 8 STORE execution (max 15 ms). Lower values risk incomplete STORE and data corruption.

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

Yes. When the device enters SLEEP mode via SPI instruction, the RTC continues running from VRTCcap or VRTCbat backup power, maintaining time, alarms, and watchdog functions. Only the SPI interface and SRAM array are powered down - the RTC oscillator and registers remain fully active.

How does hardware STORE differ from Software STORE in terms of timing and reliability?

Hardware STORE initiates immediately upon HSB pin assertion and completes within 15 ms, with HSB held LOW until done. Software STORE requires SPI command issuance and is subject to bus arbitration delays. Hardware STORE is preferred for fail-safe scenarios because it bypasses firmware latency and executes even if the host MCU is frozen or unresponsive.

Is the CY14B256PA-SFXI compatible with standard SPI flash memory drivers?

No. While it uses SPI pins and supports modes 0 and 3, its instruction set differs significantly: it requires dedicated opcodes for STORE, RECALL, RDRTC, WRTC, RDSN, and FAST_READ. Standard flash drivers will not recognize these commands and may corrupt status registers or RTC configuration without proper initialization sequence.