Renesas X4045S8I-2.7

Overview

X4045S8I-2.7 from Intersil (now Renesas) is a CPU supervisor IC integrating power-on reset control, watchdog timer, supply voltage supervision, and 4kbit serial EEPROM in a single 8-pin SOIC package. It features active-high RESET output, 2.7–5.5V operation, 2.55–2.7V VTRIP threshold, and I²C-compatible 400kHz 2-wire interface - used for microcontroller system reliability in industrial embedded controllers.

For engineers reviewing the X4045S8I-2.7 datasheet, X4045S8I-2.7 pinout, X4045S8I-2.7 application, or X4045S8I-2.7 equivalent, key selection considerations include reset polarity (active-high), programmable VTRIP range (2.55–2.7V), -40°C to +85°C temperature grade, SOIC-8 RoHS-compliant packaging, and Block Lock™ EEPROM protection granularity.

Technical Context

The X4045S8I-2.7 implements a dual-function reset architecture: power-on reset with 250ms timeout and low-VCC detection asserting RESET until VCC exceeds VTRIP for 200ms. Its watchdog timer monitors SDA/SCL activity and triggers reset if no valid I²C transaction occurs within user-selectable intervals (200ms/600ms/1.4s or disabled).

EEPROM functionality uses Intersil's Direct Write™ cell technology, enabling 1M write cycles and 100-year data retention. The 512 × 8-bit array supports 16-byte page writes with self-timed 5ms typical write cycle, and block lock protection controlled via nonvolatile BP2–BP0 bits in the 1FFh control register.

Key Specifications

Pinout & Package

Package: 8-pin JEDEC SOIC (small outline integrated circuit), Pb-free plus anneal, RoHS compliant, moisture sensitivity level (MSL) rated per IPC/JEDEC J-STD-020.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6361KA29+T, X4045S8I-2.7 adds EEPROM and programmable VTRIP but occupies more board area; compared with STM8AF6266TCY, it offers plug-and-play reliability without firmware overhead or layout changes.

Availability

X4045S8I-2.7 is available at Aetrix Electronics and suitable for industrial PLC controllers, medical diagnostic devices, smart energy meters, automotive body control modules, and portable instrumentation requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for X4045S8I-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

Renesas Electronics Corporation (formerly Intersil) is a global semiconductor leader specializing in microcontrollers, analog, power management, and timing solutions for industrial, automotive, and infrastructure markets.

The X4045S8I-2.7 belongs to the X404x CPU Supervisor family designed to consolidate power monitoring, reset generation, watchdog protection, and nonvolatile storage into a single IC - reducing system complexity and improving reliability in resource-constrained embedded systems.

FAQ

What is the reset polarity and output type of the X4045S8I-2.7?

The X4045S8I-2.7 features an active-high open-drain RESET output (pin 3). It requires an external pull-up resistor to VCC and asserts during power-up (for 250ms), brownout (when VCC falls below its 2.55–2.7V VTRIP), or watchdog timeout. This differs from the X4043 series, which provides active-low RESET.

Can the voltage threshold (VTRIP) of the X4045S8I-2.7 be adjusted, and how?

Yes, the X4045S8I-2.7 VTRIP is factory-set to 2.55–2.7V and can be reprogrammed using a high-voltage (15–18V) pulse applied to the WP pin while issuing specific I²C commands (slave address A0h, byte address 01h). The procedure supports both increasing and decreasing the threshold, with verification via controlled VCC ramp.

What EEPROM protection mechanisms does the X4045S8I-2.7 provide?

The X4045S8I-2.7 implements three-tiered EEPROM protection: hardware WP pin (disables all writes when HIGH), power-up/down write inhibit circuitry, and Block Lock™ software protection. The latter uses nonvolatile BP2–BP0 bits to lock 0, 16, 32, 64, 128, or up to 512 bytes - preventing accidental overwrites of critical firmware or calibration data.

Does the X4045S8I-2.7 support I²C communication at 400kHz, and what is its slave address?

Yes, the X4045S8I-2.7 supports standard-mode I²C up to 400kHz. Its slave address is 0xA0 (write) or 0xA1 (read) for EEPROM access, and 0xB0 (write) or 0xB1 (read) for control register access (using preamble 1011). Addressing follows standard I²C protocol with ACK polling supported during EEPROM writes.

What is the guaranteed minimum write endurance and data retention for the X4045S8I-2.7 EEPROM?

The X4045S8I-2.7 EEPROM uses Intersil's Direct Write™ technology, guaranteeing a minimum of 1,000,000 write/erase cycles and 100 years of data retention at +25°C. These values are validated across the full industrial temperature range (-40°C to +85°C) and specified in the FN8118 datasheet Rev 3.00.