Renesas R1EX24128ASAS0I#S0

Overview

R1EX24128ASAS0I from Renesas Electronics is a 128-kbit (16,384 × 8-bit) two-wire serial I²C EEPROM with 1.8 V to 5.5 V single-supply operation, 400 kHz clock frequency, and 64-byte page write capability. It delivers 2 µA max standby current, 5 ms write cycle time, and operates across −40°C to +85°C in SOP-8 packaging - deployed in industrial control modules for nonvolatile parameter storage.

For engineers reviewing the R1EX24128ASAS0I datasheet, R1EX24128ASAS0I pinout, R1EX24128ASAS0I application, or R1EX24128ASAS0I equivalent, key selection criteria include I²C bus compatibility at 400 kHz, WP-enabled hardware write protection, 100-year data retention at 25°C, and SOP-8 footprint suitability for space-constrained embedded designs.

Technical Context

This device implements a standard I²C-compatible two-wire interface with open-drain SDA and CMOS-level SCL, supporting byte and 64-byte page writes via internal address auto-increment. Its memory array uses MNOS technology with CMOS low-voltage circuitry to achieve 1,000k endurance cycles at 25°C.

The R1EX24128ASAS0I integrates hardware write protection via the WP pin, which disables all write operations when driven high, and includes noise suppression (50 ns) on SCL/SDA inputs. Device addressing uses three hardware pins (A0–A2) to support up to eight devices on a shared bus with fixed 1010 device code.

Key Specifications

Pinout & Package

Package: 150-mil 8-pin plastic SOP (PRSP0008DF-B / FP-8DBV), lead-free, surface-mount.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT24C128C-SSHL-T and M95128-DRMN6TP/K, the R1EX24128ASAS0I offers optimized balance of I²C compatibility, industrial temperature range, and hardware write protection - making it preferable for cost-sensitive, I²C-native embedded systems where 400 kHz bandwidth suffices.

Availability

R1EX24128ASAS0I is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, and smart metering applications requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for R1EX24128ASAS0I 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, and power devices for industrial, automotive, and infrastructure markets.

The R1EX24xxx series was designed specifically for robust, low-power nonvolatile storage in resource-constrained embedded systems - emphasizing reliability, wide voltage operation, and I²C simplicity over high-speed performance.

FAQ

What is the maximum I²C clock frequency supported by the R1EX24128ASAS0I?

The R1EX24128ASAS0I supports a maximum I²C clock frequency of 400 kHz, compliant with standard-mode I²C specifications. This timing is validated across the full operating voltage range (1.8 V to 5.5 V) and temperature range (−40°C to +85°C). Exceeding 400 kHz may result in unreliable communication or failed ACK responses due to internal timing constraints in the R1EX24128ASAS0I's interface logic.

Does the R1EX24128ASAS0I require external pull-up resistors on the SDA and SCL lines?

Yes, the R1EX24128ASAS0I requires external pull-up resistors on both SDA and SCL lines because its SDA pin uses an open-drain driver structure and SCL is a CMOS input. Typical values range from 2.2 kΩ to 10 kΩ depending on bus capacitance and speed; Renesas recommends verifying VOL and rise time against system-level I²C specifications when selecting resistor values for the R1EX24128ASAS0I.

How does the write protect (WP) pin function on the R1EX24128ASAS0I?

When the WP pin of the R1EX24128ASAS0I is driven high (VIH ≥ 0.7 × VCC), all write operations - including byte and page writes - are disabled, and the device responds with NACK after address reception. When WP is low (VIL ≤ 0.3 × VCC), full read/write access is enabled. This hardware-level protection prevents accidental overwrites during power transitions or firmware updates in the R1EX24128ASAS0I.

What is the endurance rating of the R1EX24128ASAS0I at 85°C ambient temperature?

The R1EX24128ASAS0I is rated for 100,000 write/erase cycles at 85°C ambient temperature, as specified in its memory cell characteristics table. This is derated from the 1,000,000-cycle rating at 25°C to account for accelerated oxide degradation at elevated temperatures. Applications operating continuously at 85°C should implement wear-leveling or write-throttling strategies to extend usable life beyond this minimum specification for the R1EX24128ASAS0I.

Can the R1EX24128ASAS0I be used in a mixed-voltage I²C system with 3.3 V and 5 V devices?

Yes, the R1EX24128ASAS0I supports 1.8 V to 5.5 V operation and has VIH and VIL thresholds defined as ratios of VCC (e.g., VIH = 0.7 × VCC), enabling interoperability in mixed-voltage I²C buses. When powered at 3.3 V, its outputs meet 5 V-tolerant input thresholds of legacy devices, and its inputs correctly interpret 3.3 V logic levels from modern MCUs - provided pull-up resistors are referenced to the appropriate voltage domain for the R1EX24128ASAS0I.