Renesas X4043S8Z

Overview

X4043S8Z from Intersil is a CPU supervisor IC integrating power-on reset control, watchdog timer, supply voltage supervision, and 4kbit EEPROM in an 8-pin SOIC package. It provides active-low reset assertion at VCC < 4.5V, supports 400kHz I²C interface, delivers <20µA standby current with watchdog enabled, and operates across 4.5–5.5V supply range - used in embedded microcontroller systems requiring reliable brownout protection and nonvolatile configuration storage.

For engineers reviewing the X4043S8Z datasheet, X4043S8Z pinout, X4043S8Z application, or X4043S8Z equivalent, this page delivers verified functional identity, validated pin roles, confirmed reset threshold (4.5–4.75V), EEPROM endurance (1M cycles), and real-world design implications for power sequencing, watchdog timeout selection, and block-lock memory protection.

Technical Context

The X4043S8Z implements a dual-stage reset architecture: power-on reset holds RESET active for ≥250ms after VCC stabilization, while low-VCC detection asserts RESET when VCC drops below 4.5V and sustains it until VCC exceeds 4.75V for ≥200ms. Its watchdog timer monitors SDA/SCL activity and triggers reset if no valid I²C start/stop sequence occurs within user-selectable intervals (200ms, 600ms, or 1.4s).

Internally, the device integrates a 512 × 8-bit EEPROM array with Block Lock™ protection, organized into 16-byte pages and accessed via standard 2-wire I²C protocol (slave address 0xA0 for memory, 0xB0 for control register). The VTRIP threshold is factory-set to 4.5–4.75V and reprogrammable using 15–18V on WP pin - a feature exclusive to the X4043/X4045 family and confirmed for X4043S8Z-4.5A variant.

Key Specifications

Pinout & Package

Package: 8-lead SOIC (Pb-free, RoHS-compliant, JEDEC standard).

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 STM8L152K4T6, the X4043S8Z uniquely combines field-programmable VTRIP, 4kbit block-locked EEPROM, and hardware watchdog - eliminating firmware dependencies while enabling precision brownout tuning and robust configuration storage in a single 8-pin SOIC.

Availability

X4043S8Z is available at Aetrix Electronics and suitable for industrial control systems, medical devices, automotive body electronics, and smart metering applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for X4043S8Z 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-performance analog and power management ICs for industrial, computing, and communications markets.

The X4043S8Z belongs to Intersil's CPU Supervisor family, engineered to consolidate reset, watchdog, voltage monitoring, and EEPROM into one die - reducing PCB area and improving system reliability in resource-constrained embedded designs.

FAQ

What is the exact reset threshold voltage range for X4043S8Z?

The X4043S8Z has a factory-programmed VTRIP range of 4.5V to 4.75V, as specified in the Ordering Information table for part number X4043S8Z-4.5A. This threshold is guaranteed across 0°C to 70°C ambient temperature and defines the voltage band where RESET is asserted during brownout conditions. The X4043S8Z datasheet confirms this value applies specifically to the -4.5A suffix variant.

Does X4043S8Z support I²C communication at standard mode (100kHz) and fast mode (400kHz)?

Yes, the X4043S8Z supports 400kHz I²C fast-mode operation as explicitly stated in the FEATURES section of the FN8118 datasheet. It uses standard I²C protocol with slave addresses 0xA0 (memory) and 0xB0 (control register), and all timing parameters - including setup/hold times and clock stretching - are validated for 400kHz operation in the Electrical Characteristics table.

Can the VTRIP threshold of X4043S8Z be reprogrammed in-circuit?

Yes, the X4043S8Z supports in-system VTRIP reprogramming using a 15–18V pulse applied to the WP pin while issuing specific I²C commands (slave address A0h, byte address 01h, data 00h). This procedure is fully documented in the FN8118 datasheet Sections 5–6 and is unique to the X4043/X4045 family - confirmed for X4043S8Z-4.5A through its inclusion in the "X4043S8Z-4.5A (Note)" ordering row.

What EEPROM protection mechanisms does X4043S8Z provide beyond software write enable?

The X4043S8Z implements three hardware-enforced EEPROM protections: (1) Power-up/power-down write inhibit circuitry that blocks writes when VCC is outside 4.5–5.5V, (2) Block Lock™ protection controlled by nonvolatile BP2/BP1/BP0 bits to lock 0–128 bytes or 1/4–full array, and (3) WP pin hardware lock disabling all writes when held HIGH - all confirmed in the FEATURES and PRINCIPLES OF OPERATION sections of FN8118 Rev 3.00.

Is X4043S8Z pin-compatible with other members of the X4043/X4045 family?

Yes, all X4043/X4045 variants - including X4043S8Z, X4043S8IZ, X4045S8Z, and X4045S8IZ - share identical 8-pin SOIC pinout and function mapping per the PIN CONFIGURATION diagram on page 4 of FN8118. The only differences are VTRIP threshold, temperature grade, and reset polarity - making them drop-in replacements for footprint and signal routing, provided system-level reset logic aligns with active-low (X4043) or active-high (X4045) output.