Renesas X4045S8IZ-4.5A

Overview

X4045S8IZ-4.5A 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 SOIC package. It provides active-high open-drain RESET output, supports 2.7V–5.5V operation, features five standard V_TRIP thresholds (4.5–4.75V for this variant), and delivers <1µA standby current with watchdog disabled.

For engineers reviewing the X4045S8IZ-4.5A datasheet, X4045S8IZ-4.5A pinout, X4045S8IZ-4.5A application, or X4045S8IZ-4.5A equivalent, key selection considerations include its -40°C to +85°C industrial temperature range, programmable V_TRIP, Block Lock™ EEPROM protection, and I²C-compatible 400kHz serial interface.

Technical Context

The X4045S8IZ-4.5A implements a dual-function reset architecture: power-on reset asserts RESET for ≥250ms after V_CC stabilization, while low-V_CC detection holds RESET active until V_CC exceeds 4.5V for ≥200ms. Its watchdog timer monitors SDA/SCL activity and offers three timeout options (200ms/600ms/1.4s) via nonvolatile WD1/WD0 bits.

EEPROM functionality uses a 512 × 8-bit array organized in 16-byte pages, supporting self-timed 5ms write cycles and Block Lock™ protection covering 0–128 bytes or ¼–full array. Communication occurs over a 2-wire I²C bus with slave address 0xA0 (array) or 0xB0 (control register), requiring external pull-ups on SDA/SCL and an external pull-up on RESET.

Key Specifications

Pinout & Package

Package: 8-pin SOIC (Pb-free, RoHS compliant), JEDEC MS-012AC, body size 4.9mm × 6.0mm, 1.27mm pitch.

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 X4045S8IZ-4.5A uniquely balances factory-trimmed 4.5V reset accuracy, field-reprogrammable V_TRIP, and 4kbit EEPROM in a pin-compatible SOIC-8 footprint - making it optimal for industrial designs requiring both robust supervision and reliable parameter storage without MCU overhead.

Availability

X4045S8IZ-4.5A is available at Aetrix Electronics and suitable for industrial motor control, medical diagnostic equipment, automotive body control modules, and smart energy meters requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for X4045S8IZ-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, communications, and computing markets.

The X4045S8IZ-4.5A belongs to Intersil's CPU Supervisor family, designed to consolidate reset generation, watchdog monitoring, voltage supervision, and nonvolatile storage into a single chip - reducing system complexity and improving reliability in resource-constrained embedded systems.

FAQ

What is the reset output polarity and drive capability of the X4045S8IZ-4.5A?

The X4045S8IZ-4.5A features an active-high open-drain RESET output (pin 3). It does not source current but pulls the line low when asserted; therefore, an external pull-up resistor to V_CC is mandatory. The output can sink ≥4mA at V_OL ≤ 0.4V, ensuring compatibility with standard CMOS/TTL reset inputs across 2.7–5.5V systems. This configuration avoids contention in multi-source reset networks.

How does the X4045S8IZ-4.5A handle brownout conditions below 1V?

The X4045S8IZ-4.5A maintains valid RESET assertion down to V_CC = 1V, ensuring deterministic reset behavior during severe brownouts. Below 1V, internal circuitry ceases operation, but RESET remains latched active until V_CC recovers above the 4.5V threshold and stabilizes for ≥200ms. This guarantees that downstream logic remains held in reset even during deep discharge of backup capacitors or battery cells.

Can the V_TRIP threshold of the X4045S8IZ-4.5A be adjusted in-circuit?

Yes, the X4045S8IZ-4.5A supports in-system V_TRIP reprogramming using a 15–18V pulse applied to the WP pin while issuing specific I²C commands (slave address 0xA0, byte address 0x01). This allows field calibration to compensate for board-level tolerances or tighten trip accuracy beyond the factory 4.5–4.75V range - a capability absent in most competing supervisors.

What EEPROM protection mechanisms does the X4045S8IZ-4.5A provide?

The X4045S8IZ-4.5A implements three-tiered EEPROM protection: (1) hardware WP pin disabling all writes when HIGH; (2) Block Lock™ software protection configurable for 16–128 bytes or ¼–full array via BP2/BP1/BP0 bits; and (3) power-loss write inhibition - writes abort automatically if V_CC drops below V_TRIP during programming. These layers prevent accidental or malicious corruption of critical calibration or configuration data.

Is the X4045S8IZ-4.5A compatible with standard I²C buses operating at 100kHz?

Yes, the X4045S8IZ-4.5A fully complies with standard-mode (100kHz) and fast-mode (400kHz) I²C specifications. Its SDA/SCL inputs meet I²C voltage thresholds and timing requirements, and its open-drain outputs support bus arbitration and multi-master operation. Pull-up resistors sized per bus capacitance (typically 2.2–4.7kΩ) ensure reliable communication alongside other I²C peripherals without protocol modification.