Renesas X5165S8

Overview

X5165S8 from Intersil is a CPU supervisor IC integrating power-on reset control, watchdog timer, supply voltage supervision, and 16Kbit SPI EEPROM in an 8-lead SOIC package. It asserts active-low RESET at VCC ≥ 1V, supports selectable watchdog timeout (200ms/600ms/1.4s), features reprogrammable VTRIP threshold (4.5–4.75V for X5165S8Z-4.5A), and operates from 4.5V to 5.5V - used in embedded microcontroller systems requiring reliable power sequencing and nonvolatile configuration storage.

For engineers reviewing the X5165S8 datasheet, X5165S8 pinout, X5165S8 application, or X5165S8 equivalent, this device delivers verified low-voltage reset assertion down to 1V, block-lock EEPROM protection, volatile flag bit for reset source identification, <50µA standby current with watchdog enabled, and SPI interface compliance with modes 0,0 and 1,1 - critical for industrial controller BOM consolidation and brownout resilience.

Technical Context

The X5165S8 implements a dual-function CS/WDI pin that serves as both chip select and watchdog input: a HIGH-to-LOW transition resets the watchdog timer, while sustained HIGH or LOW beyond the selected timeout triggers RESET assertion. Its internal VTRIP comparator uses a programmable reference enabling field-adjustable reset thresholds without hardware change.

EEPROM functionality includes 32-byte page write mode, self-timed 5ms typical write cycle, and Block Lock™ protection configurable via nonvolatile status register bits (BL0/BL1) to secure 0%, 25%, 50%, or 100% of the 16Kbit array. The device supports SPI clock frequencies up to 2MHz and maintains valid RESET output down to VCC = 1V.

Key Specifications

Pinout & Package

Package: 8-lead SOIC (RoHS-compliant, MDP0027 footprint).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6361KA29+T and STM6808RWDY6F, the X5165S8 uniquely combines field-programmable VTRIP, integrated EEPROM with block lock, and ultra-low watchdog standby current - making it optimal for applications demanding both precision brownout response and secure, self-contained configuration storage.

Availability

X5165S8 is available at Aetrix Electronics and suitable for industrial PLC controllers, medical diagnostic devices, point-of-sale terminals, and smart energy meters requiring stable component supply and long-term lifecycle support.

Supply support for X5165S8 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 and power management ICs for industrial, computing, and communications markets.

The X5165S8 belongs to Intersil's CPU Supervisor family designed to consolidate power monitoring, reset generation, watchdog safety, and nonvolatile storage into single-chip solutions for resource-constrained microcontroller systems.

FAQ

What is the factory-set VTRIP voltage for X5165S8?

The X5165S8 is shipped with a factory-programmed VTRIP threshold of 4.5V to 4.75V, specifically configured for the X5165S8Z-4.5A ordering variant. This range ensures reliable reset assertion during 5V rail brownouts while maintaining margin above typical 4.4V minimum logic supply requirements. The threshold remains stable over temperature and time unless reprogrammed using the documented VP-based sequence.

Can the watchdog timeout period be changed after soldering the X5165S8 onto a PCB?

Yes, the X5165S8 watchdog timeout period (200ms, 600ms, or 1.4s) is controlled by nonvolatile WD0/WD1 bits in the status register and can be modified in-circuit via SPI commands (WRSR instruction) at any time - including after board assembly. No external programming hardware is required, and changes persist across power cycles.

Does X5165S8 support both active-low and active-high reset outputs?

No, the X5165S8 provides only an active-low open-drain RESET output (pin 7). The "X5165" designation indicates active-low reset; the related X5163 variant offers active-high output. The X5165S8 does not include internal pull-up or polarity inversion - external pull-up resistor is required for proper logic-level reset signaling.

How is EEPROM write protection implemented on X5165S8?

X5165S8 implements multi-layer EEPROM write protection: (1) software-controlled Write Enable Latch (WEL) requiring WREN command before writes; (2) hardware WP pin combined with nonvolatile WPEN bit to lock status register writes; and (3) Block Lock™ bits (BL0/BL1) that permanently protect 0%, 25%, 50%, or 100% of the 16Kbit array from modification until explicitly reconfigured.

What is the minimum VCC required for X5165S8 to assert a valid RESET signal?

The X5165S8 asserts a valid RESET signal down to VCC = 1V, ensuring robust power-fail detection even during deep brownout conditions. RESET remains asserted until VCC rises above the programmed VTRIP threshold (4.5–4.75V) and stabilizes for 200ms, meeting JEDEC JESD8-12 requirements for reset hold time under slow-ramp power-up scenarios.