Renesas X5043S8IZ

Overview

X5043S8IZ from Renesas Electronics (formerly 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 features a 4.63V ±2.5% reset threshold, selectable watchdog timeout (200ms/600ms/1.4s), and 3.3MHz SPI interface - used for reliable microcontroller boot sequencing and nonvolatile configuration storage in industrial embedded systems.

For engineers reviewing the X5043S8IZ datasheet, X5043S8IZ pinout, X5043S8IZ application, or X5043S8IZ 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 documentation and Renesas product specifications.

Technical Context

The X5043S8IZ implements a dual-function reset architecture: power-on reset (tPURST = 200ms typical) and brownout detection with active-low open-drain RESET output asserted until VCC exceeds 4.63V and stabilizes for 200ms. Its watchdog circuit monitors CS/WDI transitions and triggers reset if no high-to-low edge occurs within the selected timeout interval.

Internally, it combines a 512 × 8-bit SPI EEPROM with Block Lock™ protection (configurable 0%, 25%, 50%, or 100% array lock), Direct Write™ memory cells (1M write cycles, 100-year retention), and a status register with nonvolatile WD0/WD1 and BL0/BL1 bits - all accessible via standard SPI opcodes including WREN, READ, WRITE, and WRSR.

Key Specifications

Pinout & Package

Package: 8-lead SOIC (Pb-free, RoHS-compliant), body width 3.9mm, pitch 1.27mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6816EUK+T and STM8AF6266TCY, the X5043S8IZ provides a fully integrated, zero-firmware solution for reset, watchdog, and EEPROM - eliminating MCU resource load and PCB layout complexity while delivering guaranteed timing and endurance specs.

Availability

X5043S8IZ is available at Aetrix Electronics and suitable for industrial process controllers, network infrastructure equipment, medical diagnostics devices, and battery-powered data loggers requiring stable component supply across extended lifecycles.

Supply support for X5043S8IZ 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 global semiconductor leader delivering trusted microcontrollers, analog, power, and connectivity solutions for automotive, industrial, and IoT markets.

The X5043S8IZ belongs to Renesas' legacy Intersil CPU Supervisor family - designed specifically to consolidate reset, watchdog, voltage monitoring, and EEPROM into one industrial-grade IC for space-constrained embedded systems.

FAQ

What is the reset threshold voltage for X5043S8IZ?

The X5043S8IZ has a factory-programmed VTRIP threshold of 4.63V ±2.5%, optimized for 4.5–5.5V supply systems. This value is reprogrammable to custom voltages (e.g., 4.6V) using a 15–18V programming pulse on the WP pin and a WREN + write-to-address-01h sequence - as documented in FN8126 Rev 3.00, pages 6–7.

Does X5043S8IZ support both active-low and active-high reset outputs?

No - the X5043S8IZ provides only an active-low open-drain RESET output. The X5045 variant (e.g., X5045S8IZ-4.5A) offers active-high RESET. The X5043S8IZ pinout and datasheet confirm RESET is active-low only; no internal configuration or external circuitry converts it to active-high.

How many watchdog timeout options does X5043S8IZ offer, and how are they selected?

The X5043S8IZ offers three watchdog timeout periods: 200ms, 600ms, and 1.4s - selected by nonvolatile WD0/WD1 bits in the status register. These bits are programmed via the WRSR instruction and retain settings across power cycles. Factory default is WD1=1, WD0=1 (watchdog disabled), per FN8126 Table 2 on page 9.

What is the maximum SPI clock frequency supported by X5043S8IZ?

The X5043S8IZ supports a maximum SPI clock frequency of 3.3MHz under recommended operating conditions (VCC = 4.5–5.5V, TA = –40°C to +85°C), as specified in the AC Electrical Specifications table (page 14 of FN8126 Rev 3.00). Exceeding this frequency risks read/write corruption or timing violations.

Can X5043S8IZ's EEPROM be partially protected, and how is that configured?

Yes - X5043S8IZ supports partial EEPROM protection via Block Lock™ using nonvolatile BL0/BL1 bits. Setting BL1=0/BL0=1 protects addresses $180–$1FF (25%), BL1=1/BL0=0 protects $100–$1FF (50%), and BL1=1/BL0=1 locks the full 512×8 array. Configuration is done via WRSR instruction, and protection persists through power cycles.