Renesas X5043PI-4.5A

Overview

X5043PI-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 PDIP package. It features a 4.63V ±2.5% reset threshold, 1.4s/600ms/200ms selectable watchdog timeout, <50µA standby current with watchdog enabled, and 512 × 8-bit block-lock protected EEPROM with 1M write endurance.

For engineers reviewing the X5043PI-4.5A datasheet, X5043PI-4.5A pinout, X5043PI-4.5A application, or X5043PI-4.5A equivalent, this device supports critical system-level reliability functions including brownout detection, microcontroller recovery, nonvolatile configuration storage, and hardware-based write protection in industrial and communications equipment.

Technical Context

The X5043PI-4.5A implements a dual-function CS/WDI pin for chip select and watchdog input, with internal reset generation triggered by VCC falling below 4.63V or watchdog timeout. Its status register contains nonvolatile WD0/WD1 bits to configure timeout and BL0/BL1 bits to enable quarter/half/full EEPROM block lock protection.

It uses a standard SPI interface (3.3MHz max) with MSB-first protocol, requiring WREN instruction before writes and supporting 1–16-byte page writes. The RESET output is active-low open-drain, asserted until VCC exceeds 4.63V for 200ms and remains valid down to VCC = 1V.

Key Specifications

Pinout & Package

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

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 STM802LSD-46F, the X5043PI-4.5A uniquely combines field-adjustable reset voltage, 1M-cycle EEPROM, and watchdog timeout persistence - enabling single-chip system reliability without design compromises.

Availability

X5043PI-4.5A is available at Aetrix Electronics and suitable for industrial process controllers, network infrastructure equipment, and desktop motherboard designs requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for X5043PI-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

Intersil (acquired by Renesas Electronics in 2017) is a semiconductor company specializing in power management, precision analog, and interface solutions for industrial and communications markets.

The X5043 family was designed to consolidate reset, watchdog, voltage monitoring, and EEPROM into one die - targeting space-constrained, high-reliability embedded systems where board real estate and component count reduction are critical.

FAQ

What is the exact reset threshold voltage of the X5043PI-4.5A?

The X5043PI-4.5A has a factory-programmed reset threshold of 4.63V ±2.5%, corresponding to the "-4.5A" suffix per the FN8126 datasheet ordering table. This value is guaranteed over temperature and supply range and remains stable unless reprogrammed using the VP=15–18V VTRIP adjustment procedure.

Does the X5043PI-4.5A support both active-low and active-high reset outputs?

No - the X5043PI-4.5A provides only an active-low RESET output (open-drain). The X5045 variant offers active-high RESET; the "X5043" designation specifically indicates active-low reset functionality. This is confirmed by pin description, truth tables, and typical application schematics in the FN8126 datasheet.

Can the watchdog timeout period of the X5043PI-4.5A be changed after power-up?

Yes - the watchdog timeout (200ms/600ms/1.4s/disabled) is controlled by nonvolatile WD0/WD1 bits in the status register. These bits can be rewritten via the WRSR instruction at any time, and their values persist across power cycles, enabling field-configurable supervision intervals without hardware changes.

What is the maximum clock frequency supported by the X5043PI-4.5A's SPI interface?

The X5043PI-4.5A supports a maximum SPI clock frequency of 3.3MHz, as specified in the AC Electrical Characteristics table (page 14 of FN8126). This applies across the full 4.5–5.5V VCC range and ensures compatibility with standard microcontroller SPI peripherals without timing margin concerns.

How does the X5043PI-4.5A handle write protection when both the WP pin and software lock bits are active?

When WP is LOW, all nonvolatile writes to the X5043PI-4.5A EEPROM and status register are disabled - overriding software-based protections. Block lock bits (BL0/BL1) and the WREN latch remain functional but ineffective. Only when WP is HIGH can software-controlled write enable and block lock operate as intended.