Renesas X4163V8-2.7A

Overview

X4163V8-2.7A from Xicor (now Renesas) is a CPU supervisor IC integrating power-on reset control, selectable watchdog timer, supply voltage supervision, and 16 Kbit serial EEPROM in an 8-pin SOIC package. It features 2.7 V to 5.5 V operation, 400 kHz I²C interface, <20 µA standby current (watchdog on), and reset assertion valid down to V_CC = 1 V - used in embedded microcontroller systems requiring reliable boot sequencing and nonvolatile configuration storage.

For engineers reviewing the X4163V8-2.7A datasheet, X4163V8-2.7A pinout, X4163V8-2.7A application, or X4163V8-2.7A equivalent, key selection criteria include programmable V_TRIP threshold (adjustable via VP programming), 200 ms reset timeout after power-up, 64-byte page write capability, and hardware write protection via WP pin and BP bits - all critical for industrial control and automotive body electronics where brownout resilience and EEPROM integrity are mandatory.

Technical Context

The X4163V8-2.7A implements a dual-function reset architecture: power-on reset with 250 ms delay and low-V_CC 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 offers three timeout options (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 cycle, and built-in write protection including Power-Up/Down lock, Block Lock (P1–P8, full array), and hardware WP-enabled locking. The device operates as a slave only, with fixed 1010xxx0 slave address and no internal address pointer reset on power-up.

Key Specifications

Pinout & Package

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

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 STM8T142M2C3, the X4163V8-2.7A uniquely balances field-programmable voltage supervision, high-speed I²C, and large EEPROM capacity - making it optimal for applications requiring post-deployment calibration tuning and robust data logging without MCU intervention.

Availability

X4163V8-2.7A is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive body control units, medical infusion pump controllers, smart energy meters, and telecom remote terminal units requiring stable component supply across extended product lifecycles.

Supply support for X4163V8-2.7A 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 Inc. was a fabless semiconductor company specializing in nonvolatile memory and power management ICs, acquired by Intersil in 2001 and later integrated into Renesas Electronics in 2017.

The X4163/5 family was designed to replace discrete reset ICs, watchdog timers, and serial EEPROMs in space-constrained embedded systems - targeting industrial automation, automotive electronics, and medical devices demanding high reliability and design simplification.

FAQ

What is the factory-default V_TRIP threshold for the X4163V8-2.7A?

The X4163V8-2.7A ships with a standard V_TRIP threshold voltage that remains stable over normal operating and storage conditions. While the exact nominal value is not specified in the provided documentation, it is one of four industry-standard thresholds - commonly 2.63 V, 2.93 V, 3.08 V, or 3.30 V - and can be reprogrammed to any desired level between 1.5 V and 5.5 V using the VP programming sequence on the WP pin.

Can the X4163V8-2.7A operate with a 3.3 V supply and still assert reset during brownout?

Yes, the X4163V8-2.7A operates from 2.7 V to 5.5 V and asserts RESET/RESET whenever V_CC falls below the programmed V_TRIP threshold - which can be set to 2.93 V or 3.08 V to match common 3.3 V system requirements. Reset remains active until V_CC rises above V_TRIP for 200 ms, ensuring clean recovery even during marginal supply conditions.

How does the watchdog timer in the X4163V8-2.7A interface with the host microcontroller?

The X4163V8-2.7A watchdog timer monitors the SDA line: a falling edge on SDA while SCL is HIGH (a valid I²C start condition) resets the timer. If no such transition occurs within the selected timeout period (200 ms, 600 ms, or 1.4 s), RESET/RESET goes active. This design allows the host MCU to service the watchdog using standard I²C bus activity without dedicated GPIO lines.

Is the EEPROM in the X4163V8-2.7A compatible with standard I²C protocols?

Yes, the X4163V8-2.7A EEPROM implements a standard 2-wire I²C interface compliant with Philips Semiconductors' specification, supporting 400 kHz fast-mode operation. It uses a fixed 7-bit slave address (1010xxx) with S0/S1 pins selecting the two LSBs, and supports byte write, 64-byte page write, current address read, random read, and sequential read - all using standard START/STOP/ACK sequences.

What happens to ongoing EEPROM writes when RESET/RESET is asserted on the X4163V8-2.7A?

When RESET/RESET goes active due to low V_CC or watchdog timeout, all ongoing I²C communications are terminated immediately. However, nonvolatile writes already in progress are allowed to complete before the device enters reset state - ensuring data integrity. New writes are blocked until RESET/RESET is deasserted and the WEL bit is explicitly set again by the host.