Renesas R1EX24256BSAS0I#U0

Overview

R1EX24256BSAS0I from Renesas Electronics is a 256-kbit (32-kword × 8-bit) two-wire serial EEPROM with I²C interface, 1.8–5.5 V single-supply operation, 400 kHz clock frequency, and 64-byte page write capability-used for nonvolatile parameter storage in embedded control modules, sensor calibration data retention, and firmware configuration backup.

For engineers reviewing the R1EX24256BSAS0I datasheet, R1EX24256BSAS0I pinout, R1EX24256BSAS0I application, or R1EX24256BSAS0I equivalent, key selection considerations include its SOP-8 package, −40°C to +85°C industrial temperature range, WP pin-based hardware write protection, 5 ms write cycle time, and MONOS memory technology enabling 1,000k endurance and 100-year data retention.

Technical Context

This device implements a standard I²C-compatible two-wire serial interface with SCL/SDA pins, fixed device code "1010", and user-configurable 3-bit slave address via A0–A2 pins-supporting up to eight devices on one bus. It uses MONOS (Metal-Oxide-Nitride-Oxide-Silicon) charge-trap memory cells fabricated on CMOS process, delivering high reliability without floating-gate wear-out mechanisms.

Internal architecture includes a serial-parallel converter, high-voltage generator for programming, address decoder (X/Y), voltage detector, and automatic page-write logic that increments lower six address bits (a₀–a₅) during multi-byte writes. Write protection is controlled by external WP pin level, with full-array lockout when WP = VIH.

Key Specifications

Pinout & Package

Package: 150-mil 8-pin plastic SOP (PRSP0008DF-B / FP-8DBV), lead-free and halogen-free (#U0 suffix), 2.5 mm body width, 1.27 mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT24C256B-PU and M95256-DRMN6TP/K, the R1EX24256BSAS0I delivers superior long-term reliability via MONOS memory, guaranteed 100-year data retention, and hardware write protection-making it optimal for industrial infrastructure where field service intervals exceed 10 years.

Availability

R1EX24256BSAS0I is available at Aetrix Electronics and suitable for industrial sensor calibration, embedded controller configuration, and firmware bootloader metadata storage requiring stable component supply, long-lifecycle assurance, and halogen-free compliance.

Supply support for R1EX24256BSAS0I 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

Renesas Electronics is a Japanese semiconductor manufacturer specializing in microcontrollers, analog, and memory solutions for industrial, automotive, and infrastructure markets.

The R1EX24xxx series was designed specifically for high-reliability, long-retention nonvolatile storage in harsh industrial environments-leveraging MONOS technology to replace aging floating-gate EEPROMs in mission-critical applications.

FAQ

What is the maximum clock frequency supported by the R1EX24256BSAS0I?

The R1EX24256BSAS0I supports a maximum I²C clock frequency of 400 kHz, as specified in its AC characteristics table. This allows reliable communication with standard microcontroller I²C peripherals while maintaining noise immunity and timing margins across the full −40°C to +85°C operating range. The R1EX24256BSAS0I does not support fast-mode plus (1 MHz) or high-speed mode.

Does the R1EX24256BSAS0I require external pull-up resistors on SDA and SCL lines?

Yes, the R1EX24256BSAS0I requires external pull-up resistors on both SDA and SCL lines because these pins use open-drain output drivers. The datasheet specifies VOL ≤ 0.4 V at IOL = 3.0 mA (VCC = 2.7–5.5 V), so resistor value must be selected based on bus capacitance, VCC level, and desired rise time-typically 2.2 kΩ to 10 kΩ for 400 kHz operation. The R1EX24256BSAS0I itself does not integrate pull-ups.

How does the write protect (WP) pin function on the R1EX24256BSAS0I?

On the R1EX24256BSAS0I, the WP pin is an active-high hardware write protection input. When WP = VIH (≥0.7 × VCC), full 256 kbit memory array is locked against write or page-write operations; only read access remains enabled. When WP = VIL (≤0.3 × VCC), normal read/write functionality is restored. The R1EX24256BSAS0I does not internally pull down WP, so it must be actively driven-not left floating-to ensure predictable behavior.

What is the endurance rating of the R1EX24256BSAS0I, and how is it achieved?

The R1EX24256BSAS0I guarantees ≥1,000,000 write/erase cycles per memory location, achieved through MONOS (Metal-Oxide-Nitride-Oxide-Silicon) charge-trap memory technology instead of conventional floating-gate structures. This eliminates gate oxide stress degradation mechanisms, enabling stable performance over extended use. The R1EX24256BSAS0I endurance is validated under JEDEC JESD22-A117 conditions and applies across the full industrial temperature range.

Is the R1EX24256BSAS0I compatible with standard I²C protocol implementations?

Yes, the R1EX24256BSAS0I implements a fully compliant standard-mode I²C interface with fixed device code "1010" and user-selectable 3-bit address (A2–A0), supporting up to eight devices on one bus. It responds to START/STOP conditions, acknowledges each byte with a ninth-cycle low pulse, and supports current-address, random, and sequential read modes-all per NXP UM10204 specification. The R1EX24256BSAS0I requires no special protocol extensions or vendor-specific drivers.