Renesas X5043S8IZ-4.5AT1

Overview

X5043S8IZ-4.5AT1 from Intersil (now Renesas) is a CPU supervisor IC integrating power-on reset control, watchdog timer, supply voltage supervision, and 4Kbit SPI EEPROM in a single 8-pin SOIC package. It features a 4.5V–5.5V V_CC range, factory-programmed 4.63V ±2.5% reset threshold, -40°C to +85°C industrial temperature rating, and active-low open-drain RESET output - used for microcontroller system stabilization in routers, industrial controllers, and network servers.

For engineers reviewing the X5043S8IZ-4.5AT1 datasheet, X5043S8IZ-4.5AT1 pinout, X5043S8IZ-4.5AT1 application, or X5043S8IZ-4.5AT1 equivalent, key selection criteria include its programmable V_TRIP capability, 200ms reset timeout, 1.4s/600ms/200ms selectable watchdog intervals, 3.3MHz SPI interface, and block-lock EEPROM protection covering 1/4, 1/2, or full memory array.

Technical Context

The X5043S8IZ-4.5AT1 implements a dual-function CS/WDI pin that serves as both chip select and watchdog input, with falling-edge-triggered watchdog reset. Its internal power-on reset circuit asserts RESET until V_CC exceeds 4.63V and remains stable for 200ms (typical), while low-voltage detection holds RESET active down to V_CC = 1V.

EEPROM operation uses SPI Mode 0 (CPOL = 0, CPHA = 0) with MSB-first transfer, supporting 1–16-byte page writes and 5ms typical write cycle time. The status register contains nonvolatile WD0/WD1 bits for watchdog timeout selection and BL0/BL1 bits for configurable block lock protection, all programmable via WRSR instruction.

Key Specifications

Pinout & Package

Package: 8-lead SOIC (Pb-free, RoHS compliant), -40°C to +85°C industrial temperature grade.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6361KA29+T and MCP9808-E/P, the X5043S8IZ-4.5AT1 uniquely combines field-adjustable reset voltage, 1M-cycle EEPROM, and multi-interval watchdog in a single 8-pin SOIC - making it the only viable choice for 5V industrial systems requiring long-term configuration resilience and brownout adaptability.

Availability

X5043S8IZ-4.5AT1 is available at Aetrix Electronics and suitable for industrial process controllers, network infrastructure equipment, and battery-powered data loggers requiring stable component supply across extended product lifecycles.

Supply support for X5043S8IZ-4.5AT1 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 (acquired by Renesas Electronics in 2017) is a semiconductor company specializing in precision analog, power management, and interface solutions for industrial, communications, and computing markets.

The X5043 family was designed as an integrated CPU supervisor platform targeting cost-sensitive, space-constrained embedded systems needing guaranteed boot reliability, runtime fault detection, and secure nonvolatile parameter storage.

FAQ

What is the factory-programmed reset threshold voltage for X5043S8IZ-4.5AT1?

The X5043S8IZ-4.5AT1 has a factory-programmed V_TRIP of 4.63V ±2.5%, corresponding to the "-4.5A" suffix per the ordering table. This threshold is set at manufacturing and remains stable over temperature and time unless explicitly reprogrammed using the high-voltage VP sequence on the WP pin. The device guarantees valid RESET assertion down to V_CC = 1V and releases RESET after V_CC exceeds 4.63V for 200ms (typical).

Does X5043S8IZ-4.5AT1 support both active-high and active-low reset outputs?

No - the X5043S8IZ-4.5AT1 provides only an active-low open-drain RESET output (pin 8). The "X5045" variant in the same datasheet offers active-high RESET, but X5043S8IZ-4.5AT1 is strictly active-low. An external pull-up resistor is required to generate a logic-high signal when RESET is inactive. The datasheet confirms RESET/RESET is active low for X5043 devices, with no internal inversion or dual-mode capability.

How is the watchdog timer enabled and configured on X5043S8IZ-4.5AT1?

The watchdog timer on X5043S8IZ-4.5AT1 is enabled by writing non-zero values to the WD0 and WD1 bits (bits 4–5) in the status register via the WRSR instruction. Default factory setting is WD1=1, WD0=1 (disabled). Valid intervals are 200ms (WD1=1, WD0=0), 600ms (WD1=0, WD0=1), or 1.4s (WD1=0, WD0=0). The timer is reset by a falling edge on the CS/WDI pin; no software command is needed for periodic refresh.

Can the EEPROM memory in X5043S8IZ-4.5AT1 be partially protected against writes?

Yes - X5043S8IZ-4.5AT1 supports four levels of block lock protection via BL0/BL1 bits in the status register: none (00), upper quarter (01), upper half (10), or full array (11). When enabled, protected blocks remain readable but reject all write attempts, even if the Write Enable Latch is set and WP is high. This hardware-based protection persists through power cycles and complements software write-enable control for robust configuration security.

What is the maximum SPI clock frequency supported by X5043S8IZ-4.5AT1?

The X5043S8IZ-4.5AT1 supports a maximum SPI clock frequency of 3.3MHz across its full operating voltage range (4.5V–5.5V) and temperature range (-40°C to +85°C). This is specified in the AC Electrical Specifications table (page 14) and applies to all operations - including READ, WRITE, RDSR, and WRSR. Exceeding 3.3MHz may cause timing violations, data corruption, or failed status register reads during write-in-progress polling.