Renesas X4045P-2.7

Overview

X4045P-2.7 from Intersil 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-high RESET output, 2.7–5.5V operation, 2.55–2.7V reset threshold, <1µA standby current (watchdog OFF), and 400kHz I²C interface - used in microcontroller-based embedded systems requiring reliable brownout protection and nonvolatile configuration storage.

For engineers reviewing the X4045P-2.7 datasheet, X4045P-2.7 pinout, X4045P-2.7 application, or X4045P-2.7 equivalent, key selection considerations include its active-high reset logic, programmable VTRIP, Block Lock™ EEPROM protection, 16-byte page write capability, and compatibility with standard I²C bus timing and addressing protocols.

Technical Context

The X4045P-2.7 implements a dual-function supervisory architecture: its low-VCC detection circuit asserts RESET when VCC drops below 2.55–2.7V and holds 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 200ms, 600ms, or 1.4s - selectable via nonvolatile WD1/WD0 bits.

Its EEPROM subsystem uses Intersil's Direct Write™ cell technology (1M write cycles, 100-year retention), organized as 512 × 8 bits, accessed via 2-wire I²C protocol with slave address 0xA0 (array) or 0xB0 (control register); block protection is controlled by BP2–BP0 bits enabling lock of 16–512 bytes or full array, while WP pin provides hardware-level write disable.

Key Specifications

Pinout & Package

Package: 8-pin PDIP (Plastic Dual In-line Package), 0.300-inch width, 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 MAX6375LCSA+ and STM8T142M2U6, the X4045P-2.7 uniquely balances field-programmable VTRIP, 4kbit protected EEPROM, and pure I²C slave simplicity - making it optimal for cost-sensitive, retrofit-friendly embedded systems needing both robust supervision and persistent parameter storage.

Availability

X4045P-2.7 is available at Aetrix Electronics and suitable for industrial PLC controllers, medical infusion pumps, smart energy meters, automotive body control modules, and battery-backed IoT edge nodes requiring stable component supply across extended product lifecycles.

Supply support for X4045P-2.7 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-2.7 belongs to Intersil's CPU Supervisor with EEPROM family, designed to reduce system cost and board area by consolidating reset, watchdog, voltage monitoring, and nonvolatile storage into one IC for microcontroller-based embedded applications.

FAQ

What is the reset output polarity and drive type of the X4045P-2.7?

The X4045P-2.7 features an active-high open-drain RESET output (pin 3). It requires an external pull-up resistor to VCC and asserts HIGH during power-up (for ≥250ms), when VCC falls below the 2.55–2.7V trip threshold, or when the watchdog timer times out. This design allows direct interfacing with microcontrollers that accept active-high reset signals and supports wired-OR configurations with other reset sources.

Can the reset threshold voltage (VTRIP) of the X4045P-2.7 be adjusted after manufacturing?

Yes, the X4045P-2.7 supports field-programmable VTRIP using a 15–18V pulse applied to the WP pin while issuing specific I²C commands. The procedure allows setting VTRIP to any value between 1.7V and the upper limit of the selected range (2.55–2.7V for X4045P-2.7), enabling fine-tuning for application-specific brownout margins without changing hardware. The X4045P-2.7 retains the programmed value indefinitely.

How does the X4045P-2.7 protect its EEPROM against unintended writes?

The X4045P-2.7 employs three-tiered write protection: (1) hardware WP pin - HIGH disables all writes; (2) Block Lock™ bits (BP2–BP0) - nonvolatile settings lock 16 to 512 bytes or full array; (3) volatile WEL/RWEL latches - require explicit enable sequences before any write. These mechanisms ensure that the X4045P-2.7 prevents corruption during power transitions, noise events, or software faults.

What is the maximum I²C clock frequency supported by the X4045P-2.7?

The X4045P-2.7 supports I²C Fast-mode operation up to 400kHz. Its SDA and SCL pins comply with standard I²C timing requirements, including setup/hold times and rise/fall characteristics. This allows seamless integration with microcontrollers and FPGAs implementing standard I²C masters - no special timing adjustments are needed when using the X4045P-2.7 in existing 400kHz bus designs.

Does the X4045P-2.7 provide watchdog timer functionality, and how is it configured?

Yes, the X4045P-2.7 includes a configurable watchdog timer that monitors SDA/SCL activity. Timeout periods of 200ms, 600ms, or 1.4s are selected via nonvolatile WD1/WD0 bits in the control register. The timer resets on valid I²C start/stop sequences and triggers RESET if no activity occurs within the selected interval. Configuration is retained across power cycles, and the X4045P-2.7 allows locking the settings via the WP pin.