Renesas X4163S8I-2.7

Overview

X4163S8I-2.7 from Xicor (now Renesas) is a CPU supervisor IC integrating power-on reset control, selectable watchdog timer, low-V_CC voltage monitoring, and 16 Kbit serial EEPROM in a single 8-pin SOIC package. It asserts active-low RESET during power-up (250 ms), brownout (down to V_CC = 1 V), or watchdog timeout; supports 400 kHz I²C interface; and operates from 2.7 V to 5.5 V. Used in embedded microcontroller systems requiring reliable boot sequencing and nonvolatile configuration storage.

For engineers reviewing the X4163S8I-2.7 datasheet, X4163S8I-2.7 pinout, X4163S8I-2.7 application, or X4163S8I-2.7 equivalent, key selection criteria include reset threshold programmability, EEPROM page-write capability (64-byte pages), watchdog timeout options (200 ms / 600 ms / 1.4 s), block-lock protection granularity, and compatibility with standard 2-wire I²C timing.

Technical Context

The X4163S8I-2.7 implements a dual-function reset architecture: power-on reset (t_PURST = 250 ms) and low-V_CC detection with four factory-set trip points (2.63 V, 2.93 V, 4.0 V, 4.38 V) - reprogrammable via VP-pulse sequence on WP pin. Its watchdog timer monitors SDA transitions while SCL is HIGH and triggers RESET if no start-bit activity occurs within the selected timeout interval.

Internally, it integrates a 2K × 8-bit EEPROM array with self-timed 5 ms typical write cycles, volatile WEL/RWEL latches for write enable control, and nonvolatile BP2–BP0 bits enabling hardware block lock of 64-byte to full-array segments. The device operates as an I²C slave (7-bit address 0xA0–0xA7) with open-drain SDA/SCL and active-low open-drain RESET output.

Key Specifications

Pinout & Package

Package: 8-lead JEDEC SOIC (SO-8), 150 mil width, RoHS-compliant.

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 STM8T142M2C6, the X4163S8I-2.7 uniquely combines field-programmable reset thresholds, 16 Kbit EEPROM with 64-byte page writes, and true hardware block lock - enabling robust, field-upgradable systems without MCU firmware dependency or external component stacking.

Availability

X4163S8I-2.7 is available at Aetrix Electronics and suitable for industrial PLC controllers, medical infusion pumps, smart energy meters, and automotive body control modules requiring stable component supply, long-term lifecycle support, and guaranteed traceability.

Supply support for X4163S8I-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

Xicor Inc., acquired by Intersil in 2001 and later by Renesas Electronics in 2017, specialized in highly integrated mixed-signal ICs for power management and nonvolatile memory interfaces.

The X4163/5 product line was designed to replace discrete reset, watchdog, and EEPROM functions in space-constrained microcontroller systems - targeting cost-sensitive, reliability-critical applications in industrial and medical end equipment.

FAQ

What is the factory-default reset threshold voltage for the X4163S8I-2.7?

The X4163S8I-2.7 ships with a factory-default V_TRIP of 2.63 V ±1.5%, optimized for 2.7 V nominal supply systems. This value is stored in nonvolatile circuitry and remains stable over temperature and time unless explicitly reprogrammed using the VP pulse method on the WP pin. The X4163S8I-2.7 datasheet specifies this as the "standard threshold" for the -2.7 suffix variant.

Can the X4163S8I-2.7 watchdog timer be disabled after power-up?

Yes, the X4163S8I-2.7 watchdog timer can be disabled by setting WD1 and WD0 bits in the Control Register to '11' - a nonvolatile operation requiring the three-step WEL/RWEL write sequence. Once disabled, the watchdog remains off across power cycles until explicitly re-enabled. The X4163S8I-2.7 does not auto-enable the watchdog on reset; its state is retained in nonvolatile memory.

How does the X4163S8I-2.7 handle EEPROM writes during a brownout event?

During brownout (V_CC < V_TRIP), the X4163S8I-2.7 asserts RESET/RESET and immediately terminates all I²C communication. Any in-progress EEPROM write is allowed to complete, but new writes are blocked until V_CC recovers and stabilizes for 200 ms. This ensures data integrity without requiring external brownout detection circuitry - a core design feature of the X4163S8I-2.7.

Is the X4163S8I-2.7 pin-compatible with other members of the X4163/5 family?

Yes, the X4163S8I-2.7 shares identical 8-pin SOIC pinout and electrical interface with all X4163/5 variants (e.g., X4163S8I-2.9, X4163S8I-4.0). Differences are limited to factory-programmed V_TRIP values and minor timing specs - allowing drop-in replacement across voltage thresholds without PCB redesign. The X4163S8I-2.7 maintains full functional and mechanical compatibility within the family.

What is the maximum write endurance of the EEPROM in the X4163S8I-2.7?

The EEPROM array in the X4163S8I-2.7 is rated for a minimum of 100,000 write/erase cycles per byte, as specified in the Xicor datasheet Rev 1.32. This endurance applies to both byte and page writes; wear leveling is not implemented, so application-level management is required for frequently updated locations. The X4163S8I-2.7 guarantees data retention for 40 years at +25°C ambient.