Renesas X4043M8IZ-2.7AT1

Overview

X4043M8IZ-2.7AT1 from Intersil (now Renesas) is a CPU supervisor IC integrating power-on reset control, watchdog timer, supply voltage supervision, and 4kbit serial EEPROM with Block Lock™ protection. It features active-low RESET output, 2.7–5.5V operation, 2.55–2.7V reset threshold, -40°C to +85°C temperature range, and 8-pin MSOP package - used in industrial microcontroller systems requiring reliable brownout recovery and nonvolatile configuration storage.

For engineers reviewing the X4043M8IZ-2.7AT1 datasheet, X4043M8IZ-2.7AT1 pinout, X4043M8IZ-2.7AT1 application, or X4043M8IZ-2.7AT1 equivalent, key selection considerations include its programmable VTRIP threshold, 400kHz I²C interface, 16-byte page write EEPROM, <1µA watchdog-OFF standby current, and open-drain RESET/RESET output with 250ms power-on delay.

Technical Context

The X4043M8IZ-2.7AT1 implements a dual-function reset architecture: power-on reset with 250ms delay and low-VCC detection asserting RESET below 2.7V (typical), holding active until VCC exceeds VTRIP for 200ms. Its watchdog timer monitors SDA/SCL activity and triggers reset if no valid I²C transaction occurs within 200ms, 600ms, or 1.4s - selectable via nonvolatile WD1/WD0 bits.

Internally, it integrates a 512 × 8-bit EEPROM array using Direct Write™ technology (1M write cycles, 100-year retention), protected by block lock bits (BP2–BP0) enabling selective write protection of 16–128 byte segments or full array. Communication uses standard 2-wire I²C protocol at up to 400kHz, with SDA/SCL open-drain inputs requiring external pull-ups and WP pin controlling global write enable.

Key Specifications

Pinout & Package

Package: 8-pin MSOP (JEDEC MO-187AA), RoHS-compliant, Pb-free plus anneal finish, -40°C to +85°C operating range.

Key Features

Applications

Equivalent & Alternatives

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

Compared with X4043S8IZ-2.7AT1, the X4043M8IZ-2.7AT1 offers identical electrical specs in a space-saving MSOP package, while MAX6361KA27+T provides a simpler, lower-cost alternative when integrated EEPROM and programmable VTRIP are not needed - making X4043M8IZ-2.7AT1 optimal for compact, self-contained supervisory designs.

Availability

X4043M8IZ-2.7AT1 is available at Aetrix Electronics and suitable for industrial automation, medical sensing, smart metering, and automotive body electronics requiring stable component supply across extended temperature and long product lifecycles.

Supply support for X4043M8IZ-2.7AT1 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, is a semiconductor company specializing in precision analog, power management, and interface solutions for industrial, communications, and computing markets.

The X4043 family was designed to consolidate power-on reset, voltage monitoring, watchdog, and EEPROM into a single chip for microcontroller-based systems - reducing BOM count, PCB area, and system-level qualification effort in cost- and reliability-sensitive applications.

FAQ

What is the factory-default reset threshold voltage for X4043M8IZ-2.7AT1?

The X4043M8IZ-2.7AT1 ships with a factory-programmed VTRIP threshold of 2.55V to 2.7V, optimized for 3.3V systems. This value is stored in nonvolatile memory and remains stable over temperature and time unless reprogrammed using the high-voltage WP sequence described in the FN8118 datasheet. The X4043M8IZ-2.7AT1 maintains reset assertion down to VCC = 1V, ensuring robust operation during deep brownouts.

Does X4043M8IZ-2.7AT1 support I²C communication at 1MHz?

No, the X4043M8IZ-2.7AT1 supports I²C communication only up to 400kHz (Fast-mode), as specified in the FN8118 datasheet. Attempting 1MHz operation will result in unreliable ACK/NACK responses and potential data corruption. The X4043M8IZ-2.7AT1's SDA and SCL inputs are designed for standard and fast-mode timing budgets; for higher-speed interfaces, a dedicated I²C buffer or faster EEPROM supervisor would be required.

How is EEPROM write protection implemented in X4043M8IZ-2.7AT1?

The X4043M8IZ-2.7AT1 implements three-tier EEPROM write protection: (1) hardware WP pin - HIGH disables all writes globally; (2) volatile WEL/RWEL latches - must be set before modifying control register bits; (3) nonvolatile BP2–BP0 bits - configure lock granularity from 16 bytes to full 512-byte array. This layered scheme ensures that the X4043M8IZ-2.7AT1 prevents accidental overwrites during power transitions and software errors while allowing controlled field updates.

Can the watchdog timeout period of X4043M8IZ-2.7AT1 be changed dynamically during operation?

Yes, the watchdog timeout period of the X4043M8IZ-2.7AT1 can be changed dynamically via the nonvolatile WD1/WD0 bits in the control register (address 1FFh), provided the WEL and RWEL latches are properly set. The four options - 200ms, 600ms, 1.4s, or disabled - persist across power cycles. However, changing the setting requires a 3-step I²C write sequence and up to 10ms nonvolatile programming time, during which the X4043M8IZ-2.7AT1 ignores further commands.

Is X4043M8IZ-2.7AT1 pin-compatible with X4045M8IZ-2.7AT1?

No, X4043M8IZ-2.7AT1 and X4045M8IZ-2.7AT1 are not pin-compatible: the X4043 variant provides active-low RESET output (pin 3), while the X4045 variant provides active-high RESET output on the same pin. Swapping them without circuit modification will invert reset logic and likely cause system malfunction. Both share identical pinout, package, and EEPROM functionality, but the X4043M8IZ-2.7AT1's RESET polarity must be matched to the host MCU's reset input requirement.