Renesas R1EX24256BSAS0A#U0

Overview

R1EX24256BSAS0A 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. It serves as nonvolatile configuration and calibration storage in embedded control modules requiring high reliability and low-power retention.

For engineers reviewing the R1EX24256BSAS0A datasheet, R1EX24256BSAS0A pinout, R1EX24256BSAS0A application, or R1EX24256BSAS0A equivalent, key selection considerations include its SOP-8 package, WP-enabled hardware write protection, 100-year data retention at 25°C, and compatibility with standard I²C timing and address decoding (1010xxxR/W).

Technical Context

This device implements a MONOS-based floating-gate memory cell architecture with CMOS low-voltage circuitry to achieve 1,000k endurance cycles at 25°C and 100-year data retention. Its I²C-compatible two-wire interface supports standard and fast-mode timing, including tLOW ≥ 1200 ns and tHIGH ≥ 600 ns at 400 kHz.

The internal address generator and serial-parallel converter enable byte and page write operations with automatic address incrementing within 64-byte boundaries. Write protect (WP) logic gates all memory writes when pulled high, while SDA open-drain output requires external pull-up and adheres to VOL ≤ 0.4 V at IOL = 3.0 mA (VCC = 2.7–5.5 V).

Key Specifications

Pinout & Package

Package: 150-mil 8-pin plastic SOP (PRSP0008DF-B / FP-8DBV), lead-free, surface-mountable with 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 R1EX24256BSAS0A delivers superior high-temperature endurance and built-in I²C multi-device addressing - making it optimal for industrial systems requiring long-term reliability and bus scalability without interface translation.

Availability

R1EX24256BSAS0A is available at Aetrix Electronics and suitable for industrial PLCs, smart energy meters, automotive body controllers, and medical infusion pumps requiring stable component supply, long-lifecycle assurance, and RoHS-compliant packaging.

Supply support for R1EX24256BSAS0A 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 Corporation is a Japanese semiconductor manufacturer specializing in microcontrollers, analog, power, and memory solutions for industrial, automotive, and enterprise applications.

The R1EX24xxx series was designed specifically for high-reliability, low-voltage embedded systems requiring robust nonvolatile storage with minimal board space - emphasizing MONOS cell longevity and I²C interoperability over cost-optimized commodity EEPROM features.

FAQ

What is the maximum I²C clock frequency supported by the R1EX24256BSAS0A?

The R1EX24256BSAS0A supports a maximum I²C clock frequency of 400 kHz, compliant with Fast-mode I²C specifications. This is confirmed in the AC Characteristics table (tLOW ≥ 1200 ns, tHIGH ≥ 600 ns) and functional description. The R1EX24256BSAS0A does not support standard-mode (100 kHz) only - it operates across the full 400 kHz range without derating.

Does the R1EX24256BSAS0A require external pull-up resistors on the SDA and SCL lines?

Yes, the R1EX24256BSAS0A requires external pull-up resistors on both SDA and SCL lines because its SDA pin has an open-drain structure and SCL is a CMOS input. 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, and desired rise time - typically 2.2 kΩ to 10 kΩ for 100–400 kHz operation. The R1EX24256BSAS0A itself does not integrate pull-ups.

How does the write protect (WP) pin function on the R1EX24256BSAS0A?

When the WP pin of the R1EX24256BSAS0A is driven high (VIH ≥ 0.7 × VCC), all write operations - including byte and page writes - are disabled, and the device returns a NO ACK ('1') after receiving write data. When WP is low (VIL ≤ 0.3 × VCC), full read/write access is enabled. WP status does not affect read operations. This hardware-level lock is active independently of I²C commands and applies to the entire 256 kbit array.

What is the endurance specification for the R1EX24256BSAS0A at 85°C?

The R1EX24256BSAS0A guarantees a minimum endurance of 100,000 write/erase cycles at 85°C, as specified in the Memory Cell Characteristics table. This is distinct from its 1,000,000-cycle rating at 25°C. The reduced endurance reflects accelerated oxide stress at elevated temperature and is fully tested per JEDEC standards - critical for applications like automotive ECUs operating continuously at high ambient temperatures.

Can the R1EX24256BSAS0A be used in a 1.8 V system?

Yes, the R1EX24256BSAS0A is fully specified for 1.8 V operation: DC Operating Conditions list VCC min = 1.8 V, and VOL1 = 0.2 V is guaranteed at IOL = 1.5 mA for VCC = 1.8–2.7 V. All AC timing (including tAA = 900 ns max) and functional behavior - including page write, acknowledge polling, and WP response - are validated down to 1.8 V. The R1EX24256BSAS0A is designed for direct integration into ultra-low-voltage IoT sensor nodes.