Renesas X4045P

Overview

X4045P from Intersil is a CPU supervisor IC integrating power-on reset control, watchdog timer, supply voltage supervision, and 4kbit serial EEPROM with Block Lock™ protection. It features active-high RESET output, 4.5–4.75V reset threshold, 2.7–5.5V supply operation, and 400kHz I²C interface - used in embedded microcontroller systems requiring reliable brownout detection and nonvolatile configuration storage.

For engineers reviewing the X4045P datasheet, X4045P pinout, X4045P application, or X4045P equivalent, this page delivers verified functional identity, exact package mapping (8-pin PDIP), confirmed VTRIP programming capability, real-world watchdog timeout options (200ms/600ms/1.4s), and validated alternative part selection guidance based on Intersil's official ordering matrix and replacement recommendations.

Technical Context

The X4045P implements a dual-function supervisory architecture: its low-VCC detector asserts RESET when VCC drops below 4.5V (typical), holding it active until VCC exceeds VTRIP for 200ms; simultaneously, its watchdog timer monitors SDA/SCL activity and triggers RESET if no valid I²C transaction occurs within the selected timeout window.

Its integrated 4kbit EEPROM uses Intersil's Direct Write™ cell technology (1M write cycles, 100-year data retention) and supports 16-byte page writes with software-configurable block lock protection across eight memory segments - all accessed via standard 2-wire I²C protocol with slave address A0h (array) or A3h (control register).

Key Specifications

Pinout & Package

Package: 8-lead PDIP (Plastic Dual In-line Package), RoHS-compliant Pb-free plus anneal finish. Pin 1 is top-left corner with notch orientation per JEDEC MS-001.

Key Features

Applications

Equivalent & Alternatives

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

Compared with X4045P, the X4045S8Z-4.5A offers identical supervision and EEPROM performance in a surface-mount package ideal for high-volume automation, while the X4045M8Z-4.5A delivers the same reliability in an ultra-compact MSOP format - both require PCB layout changes but eliminate through-hole assembly costs and improve long-term supply continuity as PDIP versions are legacy-marked.

Availability

X4045P is available at Aetrix Electronics and suitable for industrial control systems, medical instrumentation, point-of-sale terminals, and smart metering applications requiring stable component supply and long-lifecycle support.

Supply support for X4045P 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) is a semiconductor company specializing in precision analog, power management, and interface ICs for industrial, computing, and communications markets.

The X4045P belongs to Intersil's CPU Supervisor family designed to consolidate reset, watchdog, voltage monitoring, and nonvolatile storage into a single chip - reducing BOM count and improving system-level reliability in resource-constrained embedded systems.

FAQ

What is the reset output polarity and drive type of the X4045P?

The X4045P features an active-high open-drain RESET output (pin 3). It requires an external pull-up resistor to VCC and sinks current when asserted. This design allows wired-OR connection with other reset sources and ensures compatibility with both 3.3V and 5V logic families. The X4045P RESET signal is asserted during power-up, brownout, or watchdog timeout events.

Can the reset threshold voltage (VTRIP) of the X4045P be adjusted, and how is it done?

Yes, the X4045P's VTRIP is reprogrammable using a 15–18V pulse applied to the WP pin while issuing specific I²C commands. The procedure involves sending slave address A0h, byte address 01h, and data 00h - with VCC set to the desired trip voltage. The X4045P supports both increasing and decreasing VTRIP, including a reset-to-1.7V step if lowering is required. Full details are in FN8118 Rev 3.00 pages 5–7.

What are the watchdog timeout options available on the X4045P, and how are they configured?

The X4045P offers four watchdog timeout periods: 200ms, 600ms, 1.4s, or disabled - selected via nonvolatile WD1/WD0 bits in the control register (address 1FFh). Configuration requires a three-step I²C sequence: set WEL (02h), set RWEL+WEL (06h), then write final control byte. These settings persist across power cycles and can be locked by pulling WP high during normal operation. The X4045P watchdog monitors SDA/SCL transitions to detect MCU hang conditions.

How does the X4045P protect its EEPROM against unintended writes?

The X4045P implements three-tier EEPROM protection: (1) hardware WP pin - HIGH disables all writes; (2) Block Lock™ bits (BP2–BP0) - configure 8 protection modes (e.g., lock first 128 bytes or full array); (3) volatile WEL/RWEL latches - require explicit enable sequence before any write. Additionally, power-loss detection halts writes when VCC < VTRIP. All protections apply to the X4045P's 4kbit EEPROM array and control register.

Is the X4045P still in active production, and what is its recommended replacement?

The X4045P (PDIP package) is marked "no longer available" in Intersil's official ordering table (FN8118 Rev 3.00, page 2), with X4045S8Z-4.5A (SOIC-8) listed as the recommended replacement. While existing X4045P stock remains available through Aetrix Electronics, new designs should migrate to X4045S8Z-4.5A for long-term supply assurance. The X4045P retains full functional equivalence with its SOIC counterpart - only the package differs.