Renesas X5043S8I-2.7

Overview

X5043S8I-2.7 from Intersil (now Renesas) is a 4K-bit CPU supervisor IC integrating power-on reset, watchdog timer, supply voltage supervision, and SPI EEPROM in a single 8-pin SOIC package. It features a 2.85–3.0 V reset threshold, 3.3 MHz SPI interface, 100,000 write-cycle EEPROM endurance, and operates across –40°C to +85°C for industrial embedded systems requiring reliable system-level monitoring and nonvolatile configuration storage.

For engineers reviewing the X5043S8I-2.7 datasheet, X5043S8I-2.7 pinout, X5043S8I-2.7 application, or X5043S8I-2.7 equivalent, key selection criteria include its programmable VTRIP threshold, block-lock EEPROM protection, active-low RESET output with 200 ms timeout, and compatibility with microcontrollers using standard SPI protocols at 2.7–5.5 V supply.

Technical Context

The X5043S8I-2.7 implements a dual-function supervisory architecture: a precision low-VCC detector with factory-set 2.85–3.0 V trip point (reprogrammable via high-voltage VP sequence), and an independent watchdog timer with four selectable timeouts (200 ms, 600 ms, 1.4 s, or disabled) controlled by nonvolatile WD0/WD1 bits in the status register. Its SPI EEPROM uses Direct Write™ technology and supports 16-byte page writes with 5 ms typical write cycle time.

Reset assertion is triggered either by VCC falling below VTRIP (with 200 ms release delay after recovery) or by watchdog timeout due to CS/WDI inactivity. The device supports hardware write protection via WP pin and software-controlled block lock (BL0/BL1) protecting 0%, 25%, 50%, or 100% of the 512 × 8-bit array - all managed through a unified SPI command set including WREN, WRSR, READ, and WRITE.

Key Specifications

Pinout & Package

Package: 8-pin SOIC (Small Outline Integrated Circuit), RoHS-compliant Pb-free plus anneal finish, -40°C to +85°C operating temperature range.

Key Features

Applications

Equivalent & Alternatives

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

Compared with X5043S8I-2.7, MAX6361KA29+T offers identical supervisory functionality but shifts EEPROM responsibility to an external component - increasing BOM count and layout complexity, whereas X5043S8I-2.7 consolidates both functions with programmable VTRIP and block-lock security in one die.

Availability

X5043S8I-2.7 is available at Aetrix Electronics and suitable for industrial process controllers, network infrastructure equipment, medical diagnostic devices, and battery-powered IoT sensors requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for X5043S8I-2.7 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 (acquired by Renesas Electronics in 2017) is a semiconductor company specializing in high-performance analog and mixed-signal ICs for power management, precision analog, and interface applications.

The X5043 family was designed to replace discrete reset + watchdog + EEPROM solutions in space-constrained embedded systems - targeting industrial, communications, and computing applications needing guaranteed power-on sequencing and nonvolatile parameter storage.

FAQ

What is the factory-set VTRIP voltage for X5043S8I-2.7, and can it be changed?

The X5043S8I-2.7 ships with a factory-programmed VTRIP range of 2.85–3.0 V. This threshold is reprogrammable using a high-voltage (15–18 V) signal applied to the WP pin while executing a specific WREN + write-to-address-01h sequence. Reprogramming allows fine-tuning for custom rail voltages without changing the bill of materials. The X5043S8I-2.7 retains the new setting across power cycles due to nonvolatile configuration storage.

Does X5043S8I-2.7 support both active-low and active-high reset outputs?

No - the X5043S8I-2.7 provides only an active-low open-drain RESET output. It does not offer an active-high variant. The X5045 series (e.g., X5045S8I-2.7A) is the complementary part with active-high RESET. For designs requiring active-high reset, X5045S8I-2.7A must be selected instead of X5043S8I-2.7, as the two are not pin-compatible or functionally interchangeable in reset polarity.

How does the watchdog timer in X5043S8I-2.7 get reset, and what are the timeout options?

The X5043S8I-2.7 watchdog timer is reset by a HIGH-to-LOW transition on the CS/WDI pin before timeout expiration. Timeout duration is set via nonvolatile WD0/WD1 bits in the status register: 200 ms (WD1=1, WD0=0), 600 ms (WD1=0, WD0=1), 1.4 s (WD1=0, WD0=0), or disabled (WD1=1, WD0=1 - factory default). These settings persist through power cycles, ensuring consistent supervision behavior in X5043S8I-2.7 deployments.

What EEPROM protection mechanisms does X5043S8I-2.7 provide beyond the WP pin?

In addition to hardware write protection via the WP pin, the X5043S8I-2.7 implements software-controlled Block Lock™ protection using BL0/BL1 bits in the status register. These nonvolatile bits allow selective locking of 0%, 25%, 50%, or 100% of the 512 × 8-bit EEPROM array. Combined with the WREN instruction latch and CS timing requirements, this creates three independent protection layers - significantly reducing risk of accidental overwrites in X5043S8I-2.7-based systems.

Is X5043S8I-2.7 compatible with 1.8 V microcontrollers?

The X5043S8I-2.7 operates from 2.7–5.5 V and is not rated for 1.8 V VCC. While its SO output meets VOH2 specs (VCC − 0.4 V) at 2.0–3.3 V, and inputs tolerate VIH down to VCC × 0.7, the minimum functional VCC is 2.7 V per datasheet. Driving it from a 1.8 V MCU's I/O without level translation risks violating input voltage thresholds and may cause unreliable communication or reset assertion. Use level shifters or select a 1.8 V–capable supervisor if interfacing with 1.8 V logic is required for X5043S8I-2.7 integration.