Renesas X5045PI

Overview

X5045PI from Intersil (now Renesas) is a CPU supervisor IC integrating power-on reset control, watchdog timer, supply voltage supervision, and 4Kbit SPI EEPROM in a single 8-lead PDIP package. It provides active-low RESET output, selectable 200ms/600ms/1.4s watchdog timeout, 2.63V V_TRIP threshold, and operates across –40°C to +85°C for industrial microcontroller systems requiring reliable brownout protection and nonvolatile configuration storage.

For engineers reviewing the X5045PI datasheet, X5045PI pinout, X5045PI application, or X5045PI equivalent, key selection criteria include its dual-function CS/WDI pin, block-lock EEPROM protection granularity, reprogrammable V_TRIP, low 10µA standby current with watchdog disabled, and compatibility with standard SPI microcontroller interfaces at up to 3.3MHz.

Technical Context

The X5045PI implements a dedicated analog voltage monitor with hysteresis for precise 2.63V ±2.5% reset assertion and release, holding RESET active until V_CC exceeds V_TRIP for 200ms. Its watchdog timer uses the CS/WDI pin as both chip select and watchdog input, with timeout period set by nonvolatile WD0/WD1 bits in the status register.

EEPROM operation follows standard SPI protocol with MSB-first 8-bit instruction, 8-bit address, and data transfer; supports 16-byte page writes with 5ms typical write cycle time and 1M endurance using Direct Write™ cell technology. Block lock protection is controlled via BL0/BL1 bits enabling 0%, 25%, 50%, or 100% array write protection.

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 MAX6361LKA26+T, X5045PI adds watchdog supervision and reprogrammable reset threshold but requires SPI interface instead of simpler 3-wire communication; compared with MCP9800-I/P, it serves an entirely different system-level function-voltage supervision versus temperature sensing-and is not substitutable.

Availability

X5045PI is available at Aetrix Electronics and suitable for industrial process control, network infrastructure, battery-powered telemetry, and embedded computer systems requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for X5045PI 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 Corporation-acquired by Renesas Electronics in 2017-designed high-reliability analog and mixed-signal ICs for industrial, communications, and computing markets.

The X5045PI belongs to Intersil's CPU Supervisor family, engineered to consolidate reset generation, brownout detection, watchdog safety monitoring, and nonvolatile configuration storage into one compact, field-programmable device for resource-constrained embedded systems.

FAQ

What is the exact V_TRIP voltage for X5045PI and can it be modified?

The X5045PI ships with a factory-set V_TRIP of 2.63V ±2.5%. This threshold is fully reprogrammable in-system using a 15–18V programming voltage applied to the WP pin and a specific SPI command sequence-enabling precise calibration without requiring custom ordering. The X5045PI retains the new value across power cycles due to nonvolatile storage of the trip point.

Does X5045PI support both active-high and active-low reset outputs?

No-X5045PI provides only an active-low open-drain RESET output. The datasheet confirms RESET is asserted low during power-up, brownout, or watchdog timeout. There is no internal active-high variant; the "X5045" designation in ordering tables refers to the device family, not reset polarity. For active-high reset, external inversion or a different part number (e.g., X5043 series) is required.

How does the watchdog timer in X5045PI interact with the CS/WDI pin?

The CS/WDI pin serves dual roles: chip select for SPI and watchdog input. To prevent reset assertion, the microcontroller must toggle CS/WDI from high to low at least once per watchdog timeout interval (200ms/600ms/1.4s). A falling edge on CS/WDI resets the watchdog timer; if no toggle occurs before timeout expires, X5045PI asserts RESET. This design eliminates need for a dedicated WDI pin while maintaining independence from the MCU clock source.

What EEPROM protection mechanisms does X5045PI implement beyond software write enable?

X5045PI implements three hardware-enforced protections: (1) Write Protect (WP) pin-low disables all nonvolatile writes regardless of WREN state; (2) Block Lock™ bits (BL0/BL1)-nonvolatile configuration of 0%/25%/50%/100% array protection; (3) Write Enable Latch (WEL)-volatile bit requiring explicit WREN instruction before any write. All three must be satisfied for a write to proceed, preventing accidental overwrites during firmware updates or power glitches.

Is X5045PI pin-compatible with other members of the X5043/X5045 family?

Yes-X5045PI shares identical 8-lead PDIP pinout and electrical behavior with all X5043/X5045 variants in the same package (e.g., X5045PZ-2.7, X5045S8IZ-2.7). Differences are limited to V_TRIP voltage, temperature grade, and reset polarity (X5043 = active-high, X5045 = active-low). The X5045PI's –40°C to +85°C rating and 2.63V threshold make it directly swappable where those specs match system requirements.