Renesas X5045S8ZT1

Overview

X5045S8ZT1 from Intersil (now Renesas) is a 4K-bit SPI CPU supervisor IC integrating power-on reset, watchdog timer, supply voltage supervision, and block-lock protected EEPROM in an 8-lead SOIC package. It delivers 4.63V reset threshold, 1.4s watchdog timeout, 3.3MHz SPI interface, and 1M write-cycle endurance - used for reliable microcontroller supervision in industrial control and network infrastructure.

For engineers reviewing the X5045S8ZT1 datasheet, X5045S8ZT1 pinout, X5045S8ZT1 application, or X5045S8ZT1 equivalent, key selection criteria include active-low RESET output timing, reprogrammable VTRIP capability, SPI page-write mode, and dual-layer write protection via WP pin and status register BL bits.

Technical Context

The X5045S8ZT1 implements a dedicated low-voltage detection circuit with factory-trimmed 4.63V ±2.5% trip point and 200ms reset timeout, asserting RESET until VCC stabilizes above VRVALID (1V minimum). Its watchdog timer uses nonvolatile WD0/WD1 bits to select fixed timeout intervals - 1.4s (default), 600ms, or 200ms - and resets only on CS/WDI toggling before expiration.

EEPROM operation follows standard SPI protocol with MSB-first 8-bit instructions (READ/WRITE/WREN/RDSR/WRSR), supports 16-byte page writes with 5ms typical write cycle time, and enforces write protection through both hardware (WP pin) and software (BL0/BL1 bits in status register), allowing selective lock of 0%, 25%, 50%, or 100% of the 512×8 array.

Key Specifications

Pinout & Package

8-lead SOIC package (3.9mm × 4.9mm, 1.27mm pitch), RoHS-compliant Pb-free plus anneal finish, rated for 0°C to +70°C operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6361KA29+T and MCP809T-300I/P, the X5045S8ZT1 uniquely combines adjustable reset voltage, configurable watchdog, and high-endurance SPI EEPROM - making it the only option supporting firmware recovery, field calibration, and autonomous fault recovery in a single chip.

Availability

X5045S8ZT1 is available at Aetrix Electronics and suitable for industrial process controllers, network infrastructure equipment, and battery-powered data loggers requiring stable component supply across extended product lifecycles.

Supply support for X5045S8ZT1 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 (formerly Intersil) is a global semiconductor leader specializing in microcontrollers, analog, and power management solutions for industrial, automotive, and communications markets.

The X5045S8ZT1 belongs to Renesas' legacy CPU supervisor family, designed specifically to consolidate reset, watchdog, voltage monitoring, and nonvolatile storage into one robust, field-programmable IC for mission-critical embedded systems.

FAQ

What is the factory-default reset threshold voltage for the X5045S8ZT1?

The X5045S8ZT1 ships with a factory-trimmed VTRIP of 4.63V ±2.5%, corresponding to the "-4.5A" suffix in its ordering code. This threshold is guaranteed over temperature and time, and can be reprogrammed in-system using the VP programming voltage and specific WREN/write sequence to address 01h.

Does the X5045S8ZT1 support both active-low and active-high reset outputs?

No - the X5045S8ZT1 provides only an active-low open-drain RESET output. The datasheet confirms RESET/RESET is active-low; there is no active-high variant in the X5045S8ZT1 part number. For active-high reset, designers must use an external inverter or select the X5043 series counterpart.

How does the watchdog timer on the X5045S8ZT1 get reset, and what is its default timeout?

The X5045S8ZT1 watchdog timer is reset by a falling edge on the CS/WDI pin. Its default timeout is 1.4 seconds, set by WD1=0 and WD0=0 in the nonvolatile status register. This value persists across power cycles and can be changed only via WRSR instruction - not by external signals.

Can the EEPROM in the X5045S8ZT1 be written while the watchdog is enabled?

Yes - the X5045S8ZT1 allows EEPROM writes while the watchdog is enabled, provided the CS/WDI pin is toggled within the selected timeout period. However, write operations must still comply with full protection hierarchy: WREN issued, WP = HIGH, and BL bits permitting write access to target addresses.

What is the maximum SPI clock frequency supported by the X5045S8ZT1?

The X5045S8ZT1 supports a maximum SPI clock frequency of 3.3MHz under recommended operating conditions (VCC = 2.7–5.5V). This is specified in the AC Electrical Characteristics table and applies to all SPI operations including READ, WRITE, RDSR, and WRSR - enabling fast configuration and data transfer without MCU clock scaling.