Renesas X4043P-4.5A

Overview

X4043P-4.5A from Intersil (now Renesas) is a CPU supervisor IC integrating power-on reset control, watchdog timer, supply voltage supervision, and 4kbit EEPROM in a single 8-pin PDIP package. It features active-low RESET output, 4.5–4.75V reset threshold, 400kHz I²C interface, <20µA standby current with watchdog enabled, and Block Lock™ EEPROM protection. It is used in microcontroller-based embedded systems requiring reliable power sequencing and nonvolatile configuration storage.

For engineers reviewing the X4043P-4.5A datasheet, X4043P-4.5A pinout, X4043P-4.5A application, or X4043P-4.5A equivalent, key selection criteria include reset threshold accuracy, watchdog timeout configurability, EEPROM endurance (1M cycles), VCC operating range (2.7–5.5V), and compatibility with I²C bus timing requirements for system-level fault recovery and parameter retention.

Technical Context

The X4043P-4.5A implements a dual-function reset architecture: power-on reset asserts RESET for ≥250ms after VCC stabilization, while low-VCC detection holds RESET active until VCC rises above 4.5V and remains stable for 200ms. Its watchdog timer monitors SDA/SCL activity and triggers reset if no valid I²C transaction occurs within user-selectable intervals (200ms/600ms/1.4s or disabled).

EEPROM operation uses Intersil's Direct Write™ cell technology, enabling 16-byte page writes with self-timed 5ms typical write cycle time and built-in write protection via WP pin and nonvolatile block lock bits (BP2–BP0). The device supports standard I²C protocol with 7-bit slave address (1010xxx0 for memory, 1011xxx0 for control register) and acknowledges only on correct address match.

Key Specifications

Pinout & Package

Package: 8-pin PDIP (Plastic Dual In-line Package), RoHS-compliant Pb-free plus anneal finish, through-hole mounting.

Key Features

Applications

Equivalent & Alternatives

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

Compared with X4043P-4.5A, the X4043S8Z-4.5A offers identical supervision and memory functionality in a surface-mount package for automated assembly, while the X4043M8Z-4.5A delivers the same feature set in an ultra-small MSOP form factor-both retain full compatibility with existing firmware and I²C host drivers but eliminate through-hole placement requirements.

Availability

X4043P-4.5A is available at Aetrix Electronics and suitable for industrial control, medical instrumentation, automotive body electronics, and smart metering applications requiring stable component supply and long-term obsolescence management.

Supply support for X4043P-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 Corporation (formerly Intersil) is a global semiconductor leader specializing in microcontrollers, analog power, and trusted computing solutions for industrial, automotive, and infrastructure markets.

The X4043P-4.5A belongs to Renesas' legacy CPU Supervisor family, designed specifically to consolidate power management, fault recovery, and nonvolatile storage into a single IC for cost-sensitive, reliability-critical embedded systems.

FAQ

What is the reset threshold voltage range for the X4043P-4.5A?

The X4043P-4.5A has a factory-programmed reset threshold range of 4.5V to 4.75V, optimized for 5V systems. This VTRIP value is reprogrammable via a high-voltage sequence applied to the WP pin, allowing adjustment down to 1.7V or up to 4.75V for custom supply tolerance requirements. The reset signal remains valid down to VCC = 1V, ensuring robust brownout response.

Does the X4043P-4.5A support I²C communication at standard speed?

Yes, the X4043P-4.5A supports standard-mode and fast-mode I²C communication at up to 400kHz. It uses a 7-bit slave address (1010xxx0 for memory access, 1011xxx0 for control register) and complies with I²C bus timing specifications for START/STOP conditions, ACK polling, and byte/page write sequences. The SDA and SCL pins are open-drain and require external pull-up resistors.

How does the watchdog timer function in the X4043P-4.5A?

The X4043P-4.5A watchdog timer monitors SDA and SCL pin transitions to detect microcontroller activity. It resets the system if no valid I²C transaction (START–STOP sequence) occurs within the selected timeout interval-200ms, 600ms, or 1.4s-or can be disabled entirely. Timeout selection is controlled by nonvolatile WD1/WD0 bits in the status register, and the timer remains active across power cycles once configured.

Can the EEPROM in the X4043P-4.5A be protected against accidental writes?

Yes, the X4043P-4.5A provides multiple layers of EEPROM write protection: hardware-level WP pin assertion (HIGH disables all writes), software-configurable Block Lock™ via BP2–BP0 bits (protecting 0–128 bytes or 1/4–full array), and power-up/power-down protection that halts writes during VCC transitions. These mechanisms prevent corruption during brownout, firmware update, or debug sessions.

Is the X4043P-4.5A still in active production?

The X4043P-4.5A is listed in the datasheet as "no longer available" with recommended replacements X4043M8Z-4.5A (MSOP) and X4043S8Z-4.5A (SOIC). However, Aetrix Electronics maintains legacy inventory and offers lifecycle management support-including obsolescence forecasting, cross-reference guidance, and last-time-buy coordination-for continued use in existing designs requiring through-hole PDIP packaging.