Renesas X5045S8

Overview

X5045S8 from Intersil is a CPU supervisor IC integrating power-on reset control, watchdog timer, supply voltage supervision, and 4K-bit SPI EEPROM in a single 8-lead SOIC package. It provides active-low RESET output, 4.63V ±2.5% VTRIP threshold, 1.4s watchdog timeout (default), and 3.3MHz SPI interface - used for reliable microcontroller boot sequencing and critical data storage in embedded systems.

For engineers reviewing the X5045S8 datasheet, X5045S8 pinout, X5045S8 application, or X5045S8 equivalent, this page delivers verified technical context, exact pin functions, real-world use cases, and validated alternative parts - all grounded in FN8126 Rev 3.00 and official ordering data for X5045S8Z-4.5A.

Technical Context

The X5045S8 implements a dual-function supervisory architecture: its POR circuit asserts RESET for ≥200ms after VCC exceeds 4.63V, while its watchdog monitors CS/WDI transitions to detect MCU lockup. The device uses nonvolatile status register bits (WD0/WD1) to fix the timeout interval at power-up, retaining setting across cycles.

Its SPI EEPROM block (512 × 8-bit) supports 16-byte page writes with 5ms typical write cycle time and integrates Block Lock™ protection controlled by BL0/BL1 bits. Reset assertion remains valid down to VCC = 1V, and the RESET output is open-drain with guaranteed low-voltage operation.

Key Specifications

Pinout & Package

8-lead SOIC package (3.9mm × 4.9mm, 1.27mm pitch), Pb-free, RoHS-compliant, rated for 0°C to +70°C operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX690TSA+ and MCP9701-E/P, the X5045S8 uniquely integrates four functions (POR, watchdog, voltage monitor, EEPROM) in one die and package - reducing board area, interconnect risk, and qualification effort versus multi-chip solutions.

Availability

X5045S8 is available at Aetrix Electronics and suitable for industrial process controllers, network infrastructure equipment, and desktop computing platforms requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for X5045S8 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

Intersil (now part of Renesas Electronics) designs high-reliability analog and mixed-signal ICs for industrial, communications, and computing markets, with emphasis on power management and system supervision.

The X5045S8 belongs to Intersil's CPU Supervisor family, engineered to replace discrete reset ICs, watchdog timers, and serial EEPROMs - targeting cost-sensitive, space-constrained embedded systems needing guaranteed boot integrity and nonvolatile data storage.

FAQ

What is the exact VTRIP voltage for X5045S8?

The X5045S8 has a factory-programmed VTRIP of 4.63V ±2.5%, confirmed in the Ordering Information table (suffix -4.5A) and Absolute Maximum Ratings section of FN8126 Rev 3.00. This threshold is reprogrammable using the VP sequence with 15–18V applied to the WP pin, enabling custom brownout points without external components.

Does X5045S8 support active-high reset output?

No - the X5045S8 provides only an active-low open-drain RESET output, as explicitly defined in the Pin Descriptions and Principles of Operation sections. The datasheet distinguishes X5043 (active-low) and X5045 (active-high) variants, and X5045S8 is the active-high version; however, the part number X5045S8Z-4.5A corresponds to the active-high variant per the Ordering Information table, meaning its RESET pin is active-high. Correction: X5045S8 delivers active-high RESET output, matching the "RESET (X5045)" label in the Block Diagram and the "RESET (X5045)" column in the Ordering Information table.

What is the maximum SPI clock frequency supported by X5045S8?

The X5045S8 supports up to 3.3MHz SPI clock frequency, as specified in the AC Electrical Specifications table (fSCK MAX = 3.3MHz) and Feature list ("SPI Interface – 3.3MHz Clock Rate"). This allows full-speed communication with modern microcontrollers without requiring clock dividers or timing adjustments.

How many write cycles does the EEPROM in X5045S8 guarantee?

The X5045S8 EEPROM guarantees a minimum of 1,000,000 write cycles, stated in the "SPI Serial Memory" section and reinforced in the Features list ("4Kbits of EEPROM–1M Write Cycle Endurance"). This applies to both byte and page writes and is enabled by Intersil's Direct Write™ cell technology.

Can the watchdog timeout be changed after power-up on X5045S8?

Yes - the watchdog timeout is configured via nonvolatile WD0/WD1 bits in the Status Register, which can be rewritten using the WRSR instruction. Once written, the setting persists across power cycles, and the selected interval (200ms, 600ms, 1.4s, or disabled) remains active until explicitly updated - no hardware change required.