Renesas X4043M8-2.7

Overview

X4043M8-2.7 from Intersil is a CPU supervisor IC integrating power-on reset control, watchdog timer, supply voltage supervision, and 4kbit EEPROM in a single 8-pin MSOP package. It features active-low reset output, 2.7–5.5V operation, 2.55–2.7V reset threshold, 400kHz I²C interface, and <1µA standby current with watchdog disabled - used in embedded microcontroller systems requiring reliable brownout protection and nonvolatile configuration storage.

For engineers reviewing the X4043M8-2.7 datasheet, X4043M8-2.7 pinout, X4043M8-2.7 application, or X4043M8-2.7 equivalent, key selection considerations include its programmable VTRIP threshold, block-lock EEPROM protection, watchdog timeout configurability (200ms/600ms/1.4s), open-drain RESET output with 250ms power-on delay, and compatibility with standard I²C bus timing and addressing.

Technical Context

The X4043M8-2.7 implements a dual-function supervisory architecture: analog voltage monitoring with hysteresis-based low-VCC detection and digital watchdog logic tied to SDA/SCL activity. Its reset assertion remains valid down to VCC = 1V and holds for tPURST (250ms) after power-up stabilization.

EEPROM functionality uses Intersil's Direct Write™ cell technology (1M write cycles, 100-year retention), organized as 512 × 8 bits, supporting 16-byte page writes with self-timed 5ms typical write cycle. Block Lock™ protection is controlled via nonvolatile BP2–BP0 bits, enabling selective write lock of 16–128 bytes or full array segments.

Key Specifications

Pinout & Package

Package: 8-pin MSOP (JEDEC MO-187AA), RoHS-compliant, Pb-free plus anneal finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6361KA27+T and STM8T142M6U6, the X4043M8-2.7 uniquely combines field-programmable VTRIP, multi-granularity EEPROM lock, and selectable watchdog timing in one 8-pin MSOP - reducing board area and eliminating inter-component timing skew in space-constrained designs.

Availability

X4043M8-2.7 is available at Aetrix Electronics and suitable for industrial automation, medical instrumentation, smart metering, and automotive body electronics requiring stable component supply and long-term lifecycle support.

Supply support for X4043M8-2.7 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 (now part of Renesas Electronics) is a semiconductor company specializing in precision analog, power management, and interface ICs for industrial, communications, and computing markets.

The X4043M8-2.7 belongs to Intersil's CPU Supervisor family, designed to consolidate power monitoring, reset generation, watchdog safety, and nonvolatile storage into a single chip - targeting cost-sensitive, reliability-critical embedded systems where PCB real estate and BOM count are constrained.

FAQ

What is the factory-default watchdog timeout setting for the X4043M8-2.7?

The X4043M8-2.7 ships with watchdog disabled (WD1=1, WD0=1) as the factory default. This prevents unintended resets during initial system bring-up. To enable watchdog functionality, the host MCU must write the desired timeout value (200ms, 600ms, or 1.4s) to the nonvolatile control register using the three-step WEL/RWEL sequence documented in the FN8118 datasheet. The X4043M8-2.7 retains this setting across power cycles.

Can the X4043M8-2.7 reset threshold (VTRIP) be adjusted in-circuit, and what voltage is required?

Yes, the X4043M8-2.7 VTRIP threshold can be reprogrammed in-circuit using a 15–18V pulse applied to the WP pin while issuing a specific I²C command sequence (Slave Address A0h, Byte Address 01h, Data 00h). The target VTRIP voltage must be applied to VCC during programming. The X4043M8-2.7 supports both upward and downward adjustment, with a reset sequence required before lowering the threshold below its current value.

Does the X4043M8-2.7 support standard I²C addressing, and what are its slave addresses?

The X4043M8-2.7 supports two I²C slave addresses: 0xA0 (10100000b) for accessing the EEPROM array, and 0xB0 (10110000b) for accessing the control register. Both addresses use the standard 7-bit format with R/W bit appended. The X4043M8-2.7 responds with ACK only when the full 8-bit address byte matches and the device is not busy with an internal write cycle.

How does the X4043M8-2.7 handle EEPROM write protection during power transitions?

The X4043M8-2.7 implements hardware-based power transition protection: when VCC drops below VTRIP, all ongoing I²C communications terminate immediately and new writes are blocked until VCC stabilizes above VTRIP for 200ms. Additionally, the WP pin provides hardware-level write disable, and Block Lock™ bits offer software-configurable segment protection. These layers ensure that the X4043M8-2.7 cannot corrupt EEPROM contents during brownout or power-up sequences.

What is the maximum operating temperature range for the X4043M8-2.7, and is it qualified for automotive use?

Per the FN8118 datasheet, the X4043M8-2.7 is specified for 0°C to +70°C ambient operation and packaged in an 8-pin MSOP. It is not AEC-Q200 qualified and lacks automotive-grade screening or extended temperature (-40°C to +125°C) rating. For automotive body control modules, the X4043M8IZ-2.7 variant (–40°C to +85°C) is the qualified alternative - the X4043M8-2.7 is intended for commercial and industrial applications within its rated temperature envelope.