Renesas X4163PI-2.7

Overview

X4163PI-2.7 from Xicor (now Renesas) is a CPU supervisor IC integrating power-on reset control, selectable watchdog timer, low-V_CC voltage supervision, and 16 Kbit serial EEPROM in a single 8-pin SOIC package. It delivers four standard reset threshold voltages (including 2.7 V), supports 400 kHz I²C interface, operates from 2.7 V to 5.5 V, and asserts RESET/RESET down to V_CC = 1 V - enabling reliable microcontroller boot sequencing in industrial power monitoring systems.

For engineers reviewing the X4163PI-2.7 datasheet, X4163PI-2.7 pinout, X4163PI-2.7 application, or X4163PI-2.7 equivalent, key selection criteria include its factory-set 2.7 V reset threshold, nonvolatile V_TRIP reprogrammability, 64-byte page write capability, <20 µA standby current with watchdog enabled, and hardware write protection via WP pin and WPEN bit.

Technical Context

The X4163PI-2.7 implements a dual-function reset architecture: power-on reset with 250 ms timeout and brownout detection using an internal comparator referenced to a programmable V_TRIP. Its watchdog timer monitors SDA transitions during SCL HIGH and offers three fixed timeout periods (200 ms, 600 ms, 1.4 s) controlled by nonvolatile WD1/WD0 bits.

EEPROM functionality uses a 2-wire (I²C-compatible) interface with byte and 64-byte page write modes, self-timed 5 ms typical write cycles, and built-in write protection including volatile WEL/RWEL latches, nonvolatile block lock (BP2–BP0), and hardware WP-enabled locking. All nonvolatile register writes require a strict three-step sequence.

Key Specifications

Pinout & Package

Package: 8-lead JEDEC SOIC (3.9 mm × 4.9 mm, 1.27 mm pitch), RoHS-compliant, surface-mount.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6361KA27+T and STM8AF6266TCY, the X4163PI-2.7 uniquely combines factory-set 2.7 V reset, field-reprogrammable V_TRIP, 400 kHz I²C, and true EEPROM endurance in a single passive IC - eliminating MCU dependencies and enabling plug-and-play deployment in safety-critical reset paths.

Availability

X4163PI-2.7 is available at Aetrix Electronics and suitable for industrial PLC controllers, portable medical diagnostics, smart energy meters, and automotive body control modules requiring stable component supply, long-term lifecycle support, and guaranteed reset behavior under brownout conditions.

Supply support for X4163PI-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 Renesas Electronics in 2008, specialized in nonvolatile memory and power management ICs for embedded systems, emphasizing reliability, low power, and integration density.

The X4163/5 product line was designed to consolidate reset supervision, watchdog protection, and EEPROM storage into a single chip - targeting cost-sensitive, space-constrained applications in industrial automation and instrumentation where board real estate and BOM simplification are critical.

FAQ

What is the factory-set reset threshold voltage for the X4163PI-2.7?

The X4163PI-2.7 ships with a factory-programmed reset threshold of 2.7 V ±2%. This value is guaranteed over temperature and supply voltage and remains stable across normal operating life. The device asserts RESET/RESET whenever V_CC falls below this threshold and holds it active until V_CC rises above 2.7 V and remains stable for 250 ms. This exact 2.7 V trip point is confirmed in the device's "Characteristics" table and pin function description for RESET/RESET.

Can the X4163PI-2.7's reset threshold be adjusted after soldering?

Yes, the X4163PI-2.7 supports nonvolatile reprogramming of its V_TRIP threshold using a defined 3-step sequence involving the WP pin, SDA, and SCL. Applying 12–15 V to WP while holding V_CC at the desired new trip voltage initiates the programming cycle. The procedure is fully documented in the datasheet's "V_CC Threshold Reset Procedure" section and does not require special equipment - only controlled voltage sources and I²C command timing.

How does the watchdog timer in the X4163PI-2.7 get triggered?

The X4163PI-2.7 watchdog timer is triggered by the absence of a falling edge on SDA while SCL is HIGH - i.e., a valid I²C start condition - within the selected timeout period (200 ms, 600 ms, or 1.4 s). This mechanism directly monitors microcontroller I²C activity. If the host fails to issue a start bit before timeout expires, RESET/RESET goes active. The timeout is set via nonvolatile WD1/WD0 bits in the control register and persists across power cycles.

What EEPROM write protection mechanisms does the X4163PI-2.7 provide?

The X4163PI-2.7 implements layered write protection: (1) volatile WEL/RWEL latches requiring a 3-step write sequence; (2) nonvolatile block lock (BP2–BP0) enabling protection of 64-byte to full-array segments; and (3) hardware write protect via WP pin + WPEN bit, which disables all writes when both are HIGH. These features are validated in the "EEPROM Inadvertent Write Protection" and "Write Protect Enable" sections of the datasheet.

Is the X4163PI-2.7 pin-compatible with other devices in the X4163/5 family?

Yes, the X4163PI-2.7 shares identical 8-pin SOIC pinout and electrical interface with all X4163/5 variants (e.g., X4163PI-3.0, X4165PI-2.7), differing only in factory-set V_TRIP voltage and RESET/RESET polarity (X4163 = active-low, X4165 = active-high). Pin functions, I²C timing, EEPROM addressing, and control register layout are fully consistent across the family, enabling drop-in replacement where reset polarity and threshold match system requirements.