Renesas X4043S8IZ-4.5A

Overview

X4043S8IZ-4.5A from Intersil is a CPU supervisor IC integrating power-on reset control, watchdog timer, supply voltage supervision, and 4kbit EEPROM with Block Lock™ protection. It features active-low reset output, 4.5–4.75 V trip threshold, -40°C to +85°C operating range, and 400 kHz I²C interface - deployed in industrial microcontroller systems requiring reliable brownout recovery and nonvolatile configuration storage.

For engineers reviewing the X4043S8IZ-4.5A datasheet, X4043S8IZ-4.5A pinout, X4043S8IZ-4.5A application, or X4043S8IZ-4.5A equivalent, key selection criteria include reset polarity (active-low), VTRIP tolerance (±125 mV), EEPROM endurance (1M cycles), watchdog timeout options (200 ms / 600 ms / 1.4 s), and SOIC-8 Pb-free package compatibility with industrial temperature requirements.

Technical Context

The X4043S8IZ-4.5A implements a dual-function reset architecture: power-on reset asserts RESET for ≥250 ms after VCC stabilization, while low-VCC detection holds RESET active until VCC exceeds 4.5 V for ≥200 ms. Its watchdog circuit monitors SDA/SCL transitions and triggers reset if no valid I²C activity occurs within the selected timeout window.

EEPROM operation uses Intersil's Direct Write™ cell technology, enabling 5 ms typical write cycle time, 16-byte page write mode, and block lock protection configurable via nonvolatile BP2–BP0 bits. The control register (address 1FFh) requires a three-step volatile enable sequence (WEL → RWEL → data) before modifying watchdog or protection settings.

Key Specifications

Pinout & Package

Package: 8-pin SOIC (Pb-free, RoHS-compliant, JEDEC MS-012).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6361KA29+T and STM8T142M2U6, the X4043S8IZ-4.5A uniquely balances factory-trimmed 4.5 V reset accuracy, field-programmable VTRIP, and 4 kbit EEPROM in a minimal SOIC-8 footprint - making it optimal for industrial designs where supply margin validation and nonvolatile parameter storage are co-dependent requirements.

Availability

X4043S8IZ-4.5A is available at Aetrix Electronics and suitable for industrial automation, medical instrumentation, and smart metering applications requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for X4043S8IZ-4.5A 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 (now part of Renesas Electronics) is a semiconductor company specializing in precision analog, power management, and interface ICs for industrial, computing, and communications markets.

The X4043/X4045 family was designed to consolidate power supervision, watchdog, and nonvolatile memory functions into a single chip - reducing board space and improving reliability in microcontroller-based systems where robustness under voltage stress is critical.

FAQ

What is the reset output type and drive capability of the X4043S8IZ-4.5A?

The X4043S8IZ-4.5A features an active-low open-drain RESET output. It requires an external pull-up resistor (typically 4.7 kΩ to VCC) and can sink up to 4 mA while maintaining VOL ≤ 0.4 V. This design allows direct interfacing with most microcontrollers' reset inputs and supports wired-OR configurations with other reset sources. The X4043S8IZ-4.5A RESET remains asserted during power-up, brownout, and watchdog timeout conditions.

Can the VTRIP threshold of the X4043S8IZ-4.5A be adjusted, and what equipment is required?

Yes, the X4043S8IZ-4.5A supports field programming of its VTRIP threshold using a 15–18 V pulse applied to the WP pin during an I²C command sequence. No dedicated programmer is needed - only a microcontroller or I²C host capable of generating the precise START/STOP timing and applying the high-voltage pulse. The procedure is documented in the FN8118 datasheet and does not affect EEPROM data integrity. The X4043S8IZ-4.5A ships with factory-trimmed 4.5 V VTRIP but can be tuned to meet specific system margin requirements.

How does the watchdog timer in the X4043S8IZ-4.5A detect microcontroller failure?

The X4043S8IZ-4.5A watchdog monitors SDA and SCL pin transitions - not software commands - detecting any valid I²C start/stop sequence as a "heartbeat." If no such transition occurs within the selected timeout (200 ms / 600 ms / 1.4 s), it asserts RESET. This hardware-level detection prevents false resets from software hangs that leave the I²C bus idle, and eliminates dependency on periodic firmware writes. The X4043S8IZ-4.5A watchdog operates independently of the EEPROM or reset logic.

What EEPROM protection mechanisms does the X4043S8IZ-4.5A provide beyond the WP pin?

In addition to the hardware WP pin, the X4043S8IZ-4.5A implements Block Lock™ protection via nonvolatile BP2–BP0 bits in its control register. These bits allow selective write-protection of 16, 32, 64, or 128 bytes, or the upper 1/4, 1/2, or full 512-byte EEPROM array. Protection persists across power cycles and is enforced even during low-VCC conditions. The X4043S8IZ-4.5A also includes power-up/power-down write inhibit circuitry that blocks all writes when VCC is outside 2.7–5.5 V range.

Is the X4043S8IZ-4.5A pin-compatible with other members of the X4043/X4045 family?

Yes, all X4043/X4045 variants - including X4043S8Z-4.5A, X4043S8IZ-4.5A, X4045S8IZ-4.5A - share identical 8-pin SOIC pinouts and I²C protocol. The only differences are reset polarity (X4043 = active-low, X4045 = active-high) and temperature grade ('S' = 0–70°C, 'S8I' = -40–85°C). The X4043S8IZ-4.5A is functionally and physically interchangeable with X4043S8Z-4.5A in designs where extended temperature operation is required.