Renesas X5043S8IZ-4.5A

Overview

X5043S8IZ-4.5A from Intersil (now Renesas) is a CPU supervisor IC integrating power-on reset control, watchdog timer, supply voltage supervision, and 4Kbit SPI EEPROM in an 8-lead SOIC package. It features a 4.63V ±2.5% reset threshold, 200ms reset timeout, 3.3MHz SPI interface, and block-lock EEPROM protection - used in industrial process controllers to ensure deterministic boot and data integrity during brownout events.

For engineers reviewing the X5043S8IZ-4.5A datasheet, X5043S8IZ-4.5A pinout, X5043S8IZ-4.5A application, or X5043S8IZ-4.5A equivalent, key selection criteria include its -40°C to +85°C industrial temperature range, reprogrammable VTRIP capability, active-low RESET output with 1V valid operation, and support for 16-byte page writes with 5ms typical write cycle time.

Technical Context

The X5043S8IZ-4.5A implements a dual-function CS/WDI pin that serves as both chip select and watchdog input, requiring periodic toggling to prevent timeout-induced reset. Its internal power-on reset circuit asserts RESET until VCC exceeds 4.63V and remains stable for 200ms.

Voltage supervision uses a precision comparator with factory-trimmed 4.63V ±2.5% trip point, extendable via high-voltage programming sequence (VP = 15–18V applied to WP). The EEPROM array is organized as 512 × 8 bits with Direct Write™ technology enabling 1M write cycles and 100-year data retention.

Key Specifications

Pinout & Package

8-lead SOIC (Pb-free), RoHS-compliant, 150 mil body width, JEDEC MS-012AC.

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 STM802LSD-46F, the X5043S8IZ-4.5A uniquely combines field-programmable VTRIP, 1M-cycle EEPROM, and industrial temperature rating in a single 8-pin SOIC - reducing system complexity and qualifying fewer components for harsh-environment deployments.

Availability

X5043S8IZ-4.5A is available at Aetrix Electronics and suitable for industrial process controllers, network infrastructure equipment, medical devices, and battery-powered data loggers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for X5043S8IZ-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

Renesas Electronics (formerly Intersil) is a global semiconductor leader specializing in microcontrollers, analog, power management, and timing solutions for industrial, automotive, and communications markets.

The X5043 family was designed to consolidate power supervision, watchdog, and nonvolatile memory into one IC - targeting space-constrained, reliability-critical embedded systems where board real estate and component count reduction are essential.

FAQ

What is the factory-default watchdog timeout setting for the X5043S8IZ-4.5A?

The X5043S8IZ-4.5A ships with WD0=WD1=1 (binary 11), disabling the watchdog timer by default. This state persists across power cycles because the WD bits are stored in nonvolatile status register memory. To enable watchdog functionality, the host MCU must issue a WRSR command to set WD0/WD1 to 00, 01, or 10 - selecting 1.4s, 600ms, or 200ms timeout respectively. The X5043S8IZ-4.5A does not assert RESET due to watchdog expiration unless explicitly configured.

Can the reset threshold voltage of the X5043S8IZ-4.5A be adjusted in-system?

Yes, the X5043S8IZ-4.5A supports in-system VTRIP adjustment using a high-voltage programming sequence. Applying 15–18V to the WP pin while holding VCC at the desired new threshold (e.g., 4.65V) and issuing WREN followed by write 00h to address 01h reprograms the comparator trip point. This procedure is irreversible for downward adjustments - to lower VTRIP, a reset sequence (write 00h to address 03h) must first be executed. The X5043S8IZ-4.5A's programmability eliminates need for multiple BOM SKUs.

How does the X5043S8IZ-4.5A protect EEPROM contents from accidental writes?

The X5043S8IZ-4.5A employs four independent protection layers: (1) Write Enable Latch (WEL) requiring explicit WREN instruction before any write; (2) CS timing validation - CS must go high after final data bit to commit write; (3) Hardware WP pin - low state blocks all nonvolatile writes regardless of software state; (4) Block Lock bits (BL0/BL1) enabling permanent hardware protection of 25%, 50%, or 100% of EEPROM. All protections remain active during power transitions, ensuring robustness against noise or brownout-induced corruption in the X5043S8IZ-4.5A.

What is the maximum SPI clock frequency supported by the X5043S8IZ-4.5A?

The X5043S8IZ-4.5A supports a maximum SPI clock frequency of 3.3MHz across its full 4.5V–5.5V VCC range and -40°C to +85°C operating temperature. This specification is guaranteed under DC electrical test conditions with SCK rise/fall times ≤2µs and load capacitance ≤8pF. At 3.3MHz, the X5043S8IZ-4.5A achieves typical 5ms write cycle time for 16-byte page writes, enabling efficient firmware parameter updates without MCU clock rate constraints.

Does the X5043S8IZ-4.5A provide reset assertion when VCC drops below 1V?

No - the X5043S8IZ-4.5A guarantees RESET assertion only down to VCC = 1V, meaning the output remains valid and functional as supply decays to that level. Below 1V, the internal circuitry cannot maintain specified reset behavior, and RESET may deassert unpredictably. However, the X5043S8IZ-4.5A's design ensures that RESET stays asserted throughout the entire brownout event until VCC rises above 4.63V and remains stable for 200ms, providing deterministic recovery even during deep undervoltage conditions above 1V.