Renesas X5045S8IZ

Overview

X5045S8IZ 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 features a 4.63V ±2.5% reset threshold, 1.4s/600ms/200ms selectable watchdog timeout, and 3.3MHz SPI interface - deployed in industrial process controllers to ensure deterministic microcontroller startup and brownout recovery.

For engineers reviewing the X5045S8IZ datasheet, X5045S8IZ pinout, X5045S8IZ application, or X5045S8IZ equivalent, key selection criteria include its -40°C to +85°C industrial temperature range, active-low RESET output with 200ms release delay, reprogrammable VTRIP capability, and 1M write-cycle EEPROM endurance with 100-year data retention.

Technical Context

The X5045S8IZ implements a dual-function CS/WDI pin for both chip select and watchdog input, where a falling edge resets the watchdog timer. Its internal power-on reset circuit asserts RESET until VCC exceeds 4.63V and remains stable for 200ms.

Voltage supervision uses a precision comparator with factory-trimmed 4.63V ±2.5% trip point; this threshold can be reprogrammed via a high-voltage sequence (VP = 15–18V applied to WP). The EEPROM array is organized as 512 × 8 bits with block lock protection controlled by nonvolatile BL0/BL1 bits in the status register.

Key Specifications

Pinout & Package

Package: 8-lead SOIC (Pb-free, RoHS compliant), 3.9mm × 4.9mm footprint, compatible with standard SOIC-8 PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6361KA29+T and STM802LSD, the X5045S8IZ uniquely integrates reprogrammable reset voltage, three-tier watchdog timeout, and 4K-bit block-protected EEPROM - reducing BOM count and PCB area in space-constrained industrial designs.

Availability

X5045S8IZ is available at Aetrix Electronics and suitable for industrial process controllers, network routers, smart energy meters, and battery-powered telemetry nodes requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for X5045S8IZ 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 infrastructure markets.

The X5045S8IZ belongs to the X504x CPU supervisor family, designed specifically to consolidate reset, watchdog, voltage monitoring, and nonvolatile storage into a single IC for resource-constrained embedded systems.

FAQ

What is the factory-default watchdog timeout setting for the X5045S8IZ?

The X5045S8IZ ships with watchdog timer bits WD1/WD0 set to 1/1, resulting in watchdog disabled by default. This allows safe initial deployment without unintended resets. To enable watchdog functionality, the host MCU must issue a WRSR command to program WD0/WD1 to 0/0 (1.4s), 0/1 (600ms), or 1/0 (200ms). The X5045S8IZ retains this setting across power cycles due to nonvolatile storage of the status register.

Can the X5045S8IZ's 4.63V reset threshold be adjusted, and what equipment is required?

Yes, the X5045S8IZ's VTRIP can be reprogrammed to higher voltages using a 15–18V programming voltage (VP) applied to the WP pin while holding VCC at the desired new threshold. No special programmer is needed - the procedure uses standard SPI commands (WREN followed by write to address 01h). The X5045S8IZ datasheet specifies that VP must be within 15–18V and that the operation also writes 00h to EEPROM address 01h, so users must account for this side effect in their memory map.

How does the X5045S8IZ handle simultaneous write protect activation via WP pin and software write enable latch?

The X5045S8IZ implements hierarchical write protection: when WP is LOW, all nonvolatile writes (EEPROM and status register) are blocked regardless of WEL bit state. When WP is HIGH, writes require both WEL=1 (set via WREN) and correct CS timing. The X5045S8IZ datasheet confirms that WP going LOW during an active write cycle interrupts the operation, making it a robust hardware-first safeguard against firmware errors or ESD-induced glitches.

What is the maximum clock frequency supported by the X5045S8IZ's SPI interface, and how does it affect timing margins?

The X5045S8IZ supports a maximum SPI clock frequency of 3.3MHz across its full operating voltage (4.5–5.5V) and temperature (-40°C to +85°C) range. At this rate, setup/hold times remain within specification (tSU/tH ≥30ns), ensuring reliable communication with modern MCUs without requiring wait states. The X5045S8IZ's tV (output valid from clock low) is 120ns, providing ample margin for 3.3MHz operation even with PCB trace delays up to 2ns/inch.

Does the X5045S8IZ's EEPROM support page writes, and what is the page size?

Yes, the X5045S8IZ supports 16-byte page writes, where each page spans addresses ending in 0000–1111 (e.g., 0x00–0x0F, 0x10–0x1F). A single WRITE instruction can program up to 16 contiguous bytes within one page, completing in 5ms typical. Attempting to cross a page boundary causes the address counter to roll over, potentially overwriting earlier bytes - the X5045S8IZ requires firmware to manage page boundaries explicitly to avoid data corruption.