Renesas X4163S8I-2.7A

Overview

X4163S8I-2.7A from Xicor (now part of Renesas) is a CPU supervisor IC integrating power-on reset control, watchdog timer, supply voltage supervision, and 16 Kbit serial EEPROM in an 8-pin SOIC package. It features selectable watchdog timeout (200 ms / 600 ms / 1.4 s), four factory-standard V_TRIP thresholds (2.63 V, 2.93 V, 3.08 V, 4.38 V), and operates from 2.7 V to 5.5 V. It is used in microcontroller-based embedded systems requiring reliable power sequencing and nonvolatile configuration storage.

For engineers reviewing the X4163S8I-2.7A datasheet, X4163S8I-2.7A pinout, X4163S8I-2.7A application, or X4163S8I-2.7A equivalent, key selection criteria include reset assertion behavior down to V_CC = 1 V, programmable V_TRIP threshold via on-chip procedure, 400 kHz I²C-compatible 2-wire interface, and hardware write protection using WP pin and BP bits.

Technical Context

The X4163S8I-2.7A implements a dual-function reset architecture: power-on reset with 250 ms timeout and low-V_CC detection with hysteresis, asserting RESET/RESET active-low until V_CC exceeds V_TRIP for 200 ms. Its watchdog timer monitors SDA transitions during SCL HIGH and supports three fixed timeout intervals controlled by nonvolatile WD1/WD0 bits.

It integrates a 2K × 8-bit EEPROM array with 64-byte page write capability, self-timed 5 ms typical write cycle, and multi-level write protection: volatile WEL/RWEL latches, nonvolatile block lock (BP2–BP0), and hardware WP-enabled protection. Communication uses standard I²C protocol at up to 400 kHz with open-drain SDA/SCL and device-select inputs S0/S1.

Key Specifications

Pinout & Package

Package: 8-lead SOIC (JEDEC MS-012, 150 mil width), RoHS-compliant, moisture sensitivity level 3.

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 X4163S8I-2.7A uniquely balances field-programmable V_TRIP, 16 Kbit EEPROM scalability, and minimal 8-pin SOIC footprint - making it optimal for legacy and mid-volume industrial designs where precision reset tuning and memory headroom are critical.

Availability

X4163S8I-2.7A is available at Aetrix Electronics and suitable for industrial PLC controllers, portable medical diagnostics, smart energy meters, automotive body control modules, and battery-backed embedded systems requiring stable component supply across extended product lifecycles.

Supply support for X4163S8I-2.7A 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 was a fabless semiconductor company specializing in nonvolatile memory and power management ICs, acquired by Renesas Electronics in 2008. Its legacy products emphasize reliability, low-power operation, and system-level integration.

The X4163/5 product line was designed to consolidate reset, watchdog, voltage monitoring, and EEPROM functions into a single chip for cost-sensitive, space-constrained microcontroller systems - targeting industrial automation, medical instrumentation, and utility metering applications.

FAQ

What is the default watchdog timeout setting for the X4163S8I-2.7A?

The X4163S8I-2.7A ships with the watchdog timer disabled (WD1=1, WD0=1). This is the factory-default state and remains unchanged unless explicitly reconfigured via the nonvolatile control register. To enable watchdog functionality, the host MCU must execute the three-step write sequence to set WD1/WD0 to 00 (1.4 s), 01 (600 ms), or 10 (200 ms), and the X4163S8I-2.7A will retain that setting across power cycles.

Can the reset threshold voltage of the X4163S8I-2.7A be customized in-circuit?

Yes, the X4163S8I-2.7A supports in-system V_TRIP reprogramming using a defined two-phase sequence: first reset the current threshold, then apply the desired V_TRIP voltage to V_CC and 12–15 V to the WP pin while issuing specific I²C commands. This allows field calibration to match exact system rail tolerances - for example, setting V_TRIP = 3.30 V ±10 mV for a 3.3 V MCU - without requiring device replacement.

How does the X4163S8I-2.7A prevent accidental EEPROM writes during power transients?

The X4163S8I-2.7A employs three concurrent protections: (1) volatile Write Enable Latch (WEL) powers up LOW and must be explicitly set before any write; (2) nonvolatile Block Protect (BP2–BP0) bits lock memory pages; and (3) hardware Write Protect (WP) pin + WPEN bit disables all writes when both are HIGH. Critically, RESET/RESET assertion during brownout automatically terminates ongoing writes and blocks new access until V_CC stabilizes.

What I²C addressing options does the X4163S8I-2.7A support?

The X4163S8I-2.7A uses a 7-bit I²C slave address where bits [6:4] are fixed as '101', bit [3] is '0', and bits [2:1] are configured by external S0 and S1 pins (each tied HIGH/LOW). This yields four unique addresses: 0xA0, 0xA2, 0xA4, or 0xA6 - enabling up to four X4163S8I-2.7A devices on the same I²C bus without address conflict or software remapping.

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

Yes, the X4163S8I-2.7A shares identical pinout, electrical characteristics, and functional architecture with all X4163/5 variants (e.g., X4165, X4163S8I-3.0A, X4163T8I-2.7A), differing only in reset threshold voltage and package type (SOIC vs TSSOP). The 8-pin SOIC footprint and signal mapping are fully consistent across the family, allowing direct substitution where V_TRIP and package requirements align.