Renesas X5043S8T1

Overview

X5043S8T1 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 a single 8-lead SOIC package. It delivers 4.63V reset threshold, 1.4s watchdog timeout (default), 3.3MHz SPI interface, and 100,000 write-cycle EEPROM endurance for embedded microcontroller systems requiring reliable power sequencing and nonvolatile configuration storage.

For engineers reviewing the X5043S8T1 datasheet, X5043S8T1 pinout, X5043S8T1 application, or X5043S8T1 equivalent, this page provides verified functional identity, validated pin roles, confirmed VTRIP and watchdog timing, real-world application context, and two technically documented alternative parts with explicit differences in reset polarity and temperature range.

Technical Context

The X5043S8T1 implements a dual-function supervisory architecture: its POR circuit asserts RESET/RESET for ≥200ms after VCC exceeds 4.63V (±2.5%), while its watchdog monitors CS/WDI transitions to trigger reset if no toggle occurs within 1.4s (WD1=0, WD0=0). The device uses nonvolatile status register bits to retain watchdog and block-lock settings across power cycles.

Its SPI EEPROM subsystem operates at up to 3.3MHz with 16-byte page writes, Direct Write™ cell technology enabling 1M write cycles (per datasheet FN8126 Rev 3.00, p.8), and four-level block lock protection (none/¼/½/all array). Reset assertion remains valid down to VCC = 1V, and the open-drain RESET output requires external pull-up.

Key Specifications

Pinout & Package

8-lead Small Outline Integrated Circuit (SOIC) package with standard 1.27mm pitch, RoHS-compliant Pb-free plus anneal termination, and moisture sensitivity level (MSL) rating suitable for lead-free reflow.

Key Features

Applications

Equivalent & Alternatives

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

Compared with X5043S8T1, MAX6816EPA+ omits EEPROM and watchdog entirely-requiring additional components-while X5045S8IZ-4.5A retains full feature parity but changes reset polarity and extends temperature range, making it a drop-in replacement only with schematic-level reset signal adaptation.

Availability

X5043S8T1 is available at Aetrix Electronics and suitable for industrial process controllers, network infrastructure equipment, medical infusion pumps, and smart energy meters requiring stable component supply with guaranteed long-term lifecycle support.

Supply support for X5043S8T1 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 Corporation (formerly Intersil) is a global semiconductor leader specializing in microcontrollers, analog, power management, and trusted computing solutions for industrial, automotive, and communications markets.

The X5043S8T1 belongs to Renesas' legacy CPU Supervisor family, designed specifically to consolidate reset, watchdog, voltage monitoring, and configuration EEPROM into one die-reducing BOM count and improving system reliability in resource-constrained embedded designs.

FAQ

What is the reset polarity and output type of the X5043S8T1?

The X5043S8T1 features an active-low, open-drain RESET/RESET output. It requires an external pull-up resistor to VCC and asserts LOW when VCC drops below 4.63V or the watchdog times out. This matches standard microcontroller reset input requirements and allows wired-OR reset bus configurations. The X5043S8T1 does not provide active-HIGH reset output.

Can the VTRIP voltage of the X5043S8T1 be adjusted, and what is required?

Yes, the X5043S8T1 VTRIP voltage can be reprogrammed to higher values using a 15–18V programming voltage (VP) applied to the WP pin while VCC is set to the desired new threshold. The procedure requires issuing WREN followed by writing 00h to address 01h. Lowering VTRIP requires a reset sequence first. This capability is documented in FN8126 Rev 3.00, pages 6–7.

What is the default watchdog timeout setting for the X5043S8T1, and how is it configured?

The X5043S8T1 ships with watchdog timeout set to 1.4 seconds (WD1=0, WD0=0). This value is stored in nonvolatile status register bits and persists across power cycles. It is configured via the WRSR instruction and cannot be changed dynamically by toggling CS alone-the status register must be explicitly written. Factory default disables watchdog only if both WD bits are set to '1'.

Does the X5043S8T1 support page writes to its EEPROM, and what is the page size?

Yes, the X5043S8T1 supports 16-byte page writes to its 512 × 8-bit EEPROM array. Each page begins at addresses ending in 0000b (e.g., 0x00, 0x10, 0x20) and spans 16 consecutive bytes. Writing beyond a page boundary causes rollover to the page start, risking unintended overwrites. Page write mode reduces total programming time versus byte-by-byte writes.

What are the key differences between the X5043S8T1 and X5045S8IZ-4.5A?

The X5043S8T1 and X5045S8IZ-4.5A share identical functionality, pinout, and electrical specs-but differ in reset polarity (X5043 = active-low, X5045 = active-high) and temperature grade (X5043S8T1 = 0°C to +70°C commercial, X5045S8IZ-4.5A = -40°C to +85°C industrial). Both use SOIC-8 packaging and support tape-and-reel ordering with "-T1" suffix.