Renesas X5043S8IT2

Overview

X5043S8IT2 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, and 3.3MHz SPI interface for microcontroller systems requiring reliable boot sequencing and nonvolatile configuration storage.

For engineers reviewing the X5043S8IT2 datasheet, X5043S8IT2 pinout, X5043S8IT2 application, or X5043S8IT2 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 X5043S8IT2 implements a dual-function supervisory architecture: its POR circuit asserts RESET/RESET for ≥200ms after VCC exceeds 4.63V, while its watchdog monitors CS/WDI transitions to trigger reset if no toggle occurs within 1.4s (WD1=0, WD0=0 default). The device uses a nonvolatile status register to store watchdog and block-lock configuration bits across power cycles.

Its SPI EEPROM core operates at up to 3.3MHz with 16-byte page writes and 5ms typical write cycle time, backed by Direct Write™ technology enabling 1M write endurance and 100-year data retention. Block lock protection (BL0/BL1 bits) allows selective write-protection of 0%, 25%, 50%, or 100% of the 512×8 array.

Key Specifications

Pinout & Package

Package: 8-lead SOIC (Small Outline Integrated Circuit), RoHS-compliant Pb-free plus anneal finish, 150 mil width.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6361KA29+T, X5043S8IT2 offers 16× more EEPROM, field-adjustable VTRIP, and finer watchdog control; versus X5045S8IZ-4.5A, it differs solely in reset polarity-both share identical timing, protection, and memory features.

Availability

X5043S8IT2 is available at Aetrix Electronics and suitable for industrial process controllers, network infrastructure equipment, and battery-powered IoT gateways requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for X5043S8IT2 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, now part of Renesas Electronics, designs high-performance analog and mixed-signal ICs for power management, precision sensing, and system supervision.

The X5043 family was developed to consolidate reset, watchdog, voltage monitoring, and EEPROM functions into a single chip for cost-sensitive, space-constrained microcontroller-based systems in industrial and communications markets.

FAQ

What is the reset polarity and output type of the X5043S8IT2?

The X5043S8IT2 features an active-low, open-drain RESET/RESET output. This means the pin pulls low during reset conditions-including power-up, brownout (VCC < 4.63V), and watchdog timeout-and requires an external pull-up resistor to VCC for proper logic-level signaling. The X5043S8IT2 does not provide active-high reset; that function is implemented in the pin-compatible X5045 variant.

How is the watchdog timeout period configured on the X5043S8IT2?

The watchdog timeout on the X5043S8IT2 is set via two nonvolatile bits (WD0 and WD1) in the status register, programmed using the WRSR instruction. By default (WD1=0, WD0=0), it is 1.4 seconds. Other options are 200ms, 600ms, or disabled. These settings persist across power cycles and do not require reconfiguration after each startup.

Can the reset threshold voltage of the X5043S8IT2 be modified after soldering?

Yes, the VTRIP threshold of the X5043S8IT2 can be reprogrammed in-system using a dedicated SPI sequence: apply the desired VTRIP voltage to VCC, tie WP to 15–18V, issue WREN, then write 00h to address 01h. This capability enables field calibration for tighter voltage tolerance or custom brownout points without replacing the component.

What EEPROM protection mechanisms does the X5043S8IT2 support?

The X5043S8IT2 supports four layers of EEPROM protection: (1) Write Enable Latch (WREN/WRDI), (2) Hardware WP pin (LOW disables all writes), (3) Block Lock bits (BL0/BL1) for 0%/25%/50%/100% array protection, and (4) Status register write lock. All are independently controllable and retain settings across power loss.

Is the X5043S8IT2 compatible with standard SPI interfaces operating at 3.3V logic levels?

Yes, the X5043S8IT2 is fully compatible with 3.3V SPI buses. Its SI, SO, SCK, and CS inputs meet standard 3.3V logic thresholds (VIH ≥ 2.31V, VIL ≤ 1.0V), and SO provides push-pull output with VOH ≥ VCC–0.8V at 1mA load. It operates across VCC = 2.7–5.5V, making it interoperable with both 3.3V and 5V microcontrollers.