Renesas X4283S8I-4.5A

Overview

X4283S8I-4.5A from Xicor (now part of Renesas) is a CPU supervisor IC integrating power-on reset control, watchdog timer, supply voltage supervision, and 128 Kbit serial EEPROM with Block Lock™ protection. It features 4.5 V reset threshold, 400 kHz I²C interface, <1 µA standby current (watchdog off), and operates from 2.7 V to 5.5 V - used in embedded microcontroller systems requiring reliable boot integrity and nonvolatile configuration storage.

For engineers reviewing the X4283S8I-4.5A datasheet, X4283S8I-4.5A pinout, X4283S8I-4.5A application, or X4283S8I-4.5A equivalent, key selection criteria include programmable V_TRIP threshold (factory-set to 4.5 V), three selectable watchdog timeout periods (200 ms / 600 ms / 1.4 s), 64-byte page write EEPROM, hardware write protection via WP pin, and SOIC-8 package compatibility with industrial temperature range (–40°C to +85°C).

Technical Context

The X4283S8I-4.5A implements a dual-function reset architecture: power-on reset with 250 ms delay and low-V_CC detection asserting RESET/RESET down to V_CC = 1 V. Its watchdog timer monitors SDA transitions during SCL HIGH to detect MCU lockup, with timeout period controlled by nonvolatile WD1/WD0 bits.

EEPROM operation uses a 2-wire (I²C-compatible) interface with slave address 1010xxxR, supports byte and 64-byte page writes (5 ms typical), and includes hardware/software write protection via WP pin, WPEN bit, and BP2–BP0 block lock bits - protecting segments from 64 bytes to full 16 KB array.

Key Specifications

Pinout & Package

Package: 8-pin SOIC (JEDEC MS-012, 150 mil width), RoHS-compliant, moisture sensitivity level MSL3.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar CPU supervisor with integrated EEPROM applications.

Compared with MAX6361KA29+T and STM8T142M2U6, the X4283S8I-4.5A uniquely delivers factory-trimmed 4.5 V reset, field-reprogrammable threshold, and 400 kHz I²C in an SOIC-8 footprint - making it optimal for retrofitting robust supervision into space-constrained 5 V microcontroller platforms without layout changes.

Availability

X4283S8I-4.5A is available at Aetrix Electronics and suitable for industrial automation, medical device manufacturing, and automotive electronics requiring stable component supply, long-term lifecycle support, and guaranteed traceability.

Supply support for X4283S8I-4.5A 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

Xicor was a fabless semiconductor company specializing in nonvolatile memory and power management ICs, acquired by Renesas Electronics in 2008. Its legacy products emphasize reliability, low-power design, and system-level integration.

The X4283 family was designed to consolidate reset, watchdog, voltage monitoring, and EEPROM functions into a single chip for microcontroller-based systems - reducing bill-of-materials cost and improving board-level reliability in mission-critical applications.

FAQ

What is the factory-programmed reset threshold voltage for X4283S8I-4.5A?

The X4283S8I-4.5A is shipped with a factory-programmed V_TRIP of 4.5 V ±1.5%, verified per Rev 1.21 datasheet. This threshold is stored in nonvolatile circuitry and remains stable over temperature and time unless explicitly reprogrammed using the VP=12–15 V sequence on the WP pin. The 4.5 V setting targets systems powered from regulated 5 V rails where brownout detection must occur before logic levels degrade.

Can the watchdog timeout period of X4283S8I-4.5A be changed after soldering?

Yes, the watchdog timeout period of X4283S8I-4.5A can be reconfigured in-system via I²C writes to the Control Register (address FFFFh). WD1 and WD0 bits support 200 ms, 600 ms, 1.4 s, or disabled states. The change persists through power cycles and requires no external hardware - but WP pin must be LOW and WPEN bit cleared to allow register modification. Factory default is disabled (WD1=1, WD0=1).

Does X4283S8I-4.5A support standard I²C addressing and protocol?

Yes, X4283S8I-4.5A implements full I²C compliance: 7-bit slave address format (1010xxxR), START/STOP condition detection, ACK/NACK handshaking, and 400 kHz clock tolerance. Device select pins S0/S1 define the two LSBs (xxx), enabling up to four X4283S8I-4.5A units on one bus. It supports byte write, 64-byte page write, current address read, random read, and sequential read - all per standard I²C timing diagrams in the datasheet.

How does hardware write protection work on X4283S8I-4.5A?

Hardware write protection on X4283S8I-4.5A activates when both the WP pin is driven HIGH and the WPEN bit (bit 7 of Control Register) is set to 1. When enabled, it blocks all writes to EEPROM and Control Register - including Block Lock bits and watchdog settings. Unlike software-only protection, this cannot be overridden by I²C commands. To disable, WP must be pulled LOW *before* powering up, as WPEN is nonvolatile and cannot be cleared while WP is HIGH.

Is X4283S8I-4.5A pin-compatible with other X4283 variants like X4283S8I-3.08A?

Yes, X4283S8I-4.5A is mechanically and electrically pin-compatible with all X4283/X4285 family members in SOIC-8 and TSSOP-8 packages, including X4283S8I-3.08A and X4285S8I-4.5A. Pin functions, timing, I²C protocol, and register map are identical. The sole difference is factory-programmed V_TRIP voltage - 4.5 V for X4283S8I-4.5A versus 3.08 V for X4283S8I-3.08A - allowing direct substitution where system voltage thresholds align.