Renesas X4163S8-2.7

Overview

X4163S8-2.7 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 X4163S8-2.7 datasheet, X4163S8-2.7 pinout, X4163S8-2.7 application, or X4163S8-2.7 equivalent, key selection criteria include reset threshold accuracy, watchdog programmability, EEPROM page-write capability (64-byte pages), low-voltage reset validity down to 1 V, and hardware write protection via WP pin and Block Lock bits.

Technical Context

The X4163S8-2.7 implements a dual-function reset architecture: power-on reset with 250 ms timeout and brownout detection with hysteresis, asserting active-low RESET/RESET until V_CC exceeds V_TRIP for 200 ms. Its watchdog timer monitors SDA transitions during SCL HIGH and supports three fixed timeout intervals set by nonvolatile WD1/WD0 bits.

It uses a 2-wire (I²C-compatible) interface at up to 400 kHz, with open-drain SDA/SCL, built-in write protection logic (WEL/RWEL latches), and EEPROM block lock controlled by BP2–BP0 bits. The device supports reprogrammable V_TRIP using a high-voltage (12–15 V) pulse on WP while applying the target threshold to V_CC.

Key Specifications

Pinout & Package

Package: 8-lead JEDEC SOIC (SO-8), 150 mil width, surface-mount.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6361KA26-T and STM8T142M2U6, the X4163S8-2.7 uniquely balances field-programmable reset voltage, hardware-enforced EEPROM protection, and zero-software overhead - making it optimal for cost-constrained, safety-critical embedded systems requiring guaranteed data integrity without MCU intervention.

Availability

X4163S8-2.7 is available at Aetrix Electronics and suitable for industrial PLC controllers, medical diagnostic devices, smart energy meters, automotive body control modules, and embedded IoT gateways requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for X4163S8-2.7 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 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 replace discrete reset ICs, watchdog timers, and serial EEPROMs in space-constrained embedded systems - targeting applications where board area, BOM count, and power integrity are critical design constraints.

FAQ

What is the factory-default V_TRIP threshold for X4163S8-2.7?

The X4163S8-2.7 ships with a factory-default V_TRIP threshold of 2.63 V ±1.5%. This value is laser-trimmed and stable over temperature and time. It is one of four standard thresholds (2.63 V, 2.93 V, 3.08 V, 4.38 V) supported by the device, and can be reprogrammed to a custom voltage using the WP pin programming sequence described in the datasheet. The X4163S8-2.7 maintains this setting across power cycles without external components.

Does X4163S8-2.7 support I²C Fast Mode (400 kHz)?

Yes, the X4163S8-2.7 fully supports I²C Fast Mode at up to 400 kHz. Its SDA and SCL pins meet standard I²C electrical specifications, including open-drain outputs with defined rise/fall times and noise immunity. The device responds to standard 7-bit slave addresses (1010xxxR/W format) and implements full acknowledge polling, random read, sequential read, and page-write protocols per the I²C specification. No additional timing constraints apply beyond those specified in the X4163S8-2.7 datasheet.

How does the watchdog timer in X4163S8-2.7 get reset?

The watchdog timer in X4163S8-2.7 is reset by a HIGH-to-LOW transition on the SDA pin while SCL is held HIGH - matching the I²C start condition. This design allows the host MCU to service the watchdog using normal I²C bus activity without dedicated GPIO toggling. If no such transition occurs within the selected timeout interval (200 ms / 600 ms / 1.4 s), the device asserts RESET/RESET. The timeout is set nonvolatily via WD1/WD0 bits and persists across power cycles unless rewritten.

Can X4163S8-2.7's EEPROM be written to while RESET/RESET is active?

No. While RESET/RESET is active - whether due to power-on, brownout, or watchdog timeout - the X4163S8-2.7 disables all I²C communication and blocks new write operations. In-progress writes are allowed to complete, but no new commands (including EEPROM writes or Control Register updates) are accepted until RESET/RESET deasserts. This behavior is hardwired and ensures data integrity during supply instability, a core design requirement validated in the X4163S8-2.7 characterization.

What is the function of the S0 and S1 pins on X4163S8-2.7?

The S0 and S1 pins on X4163S8-2.7 configure the two most significant bits (A1, A0) of the I²C slave address, enabling up to four X4163S8-2.7 devices on the same bus. S0 maps to A0 and S1 to A1 in the 7-bit address format (1010 S1 S0 R/W). These pins are sampled at power-up and remain static during operation. They do not affect reset behavior, watchdog timing, or EEPROM functionality - their sole purpose is I²C address differentiation in multi-device systems.