Renesas X4283S8

Overview

X4283S8 from Xicor (now part of Renesas) is a CPU supervisor IC integrating power-on reset control, selectable watchdog timer, low-V_CC detection, and 128 Kbit serial EEPROM with Block Lock™ protection. It operates from 2.7V to 5.5V, delivers reset assertion down to V_CC = 1V, supports 400 kHz I²C interface, and features <20 µA standby current with watchdog enabled. It is used in embedded microcontroller systems requiring reliable power sequencing and nonvolatile configuration storage.

For engineers reviewing the X4283S8 datasheet, X4283S8 pinout, X4283S8 application, or X4283S8 equivalent, key selection considerations include its programmable V_TRIP threshold (adjustable via VP programming), three watchdog timeout options (200 ms / 600 ms / 1.4 s), 64-byte page write capability, hardware/software write protection scheme, and dual 8-lead SOIC/TSSOP package compatibility.

Technical Context

The X4283S8 implements a dedicated analog voltage monitor for precise low-V_CC detection with factory-set or user-programmable trip points (1.6V–4.65V range), and asserts an open-drain RESET/RESET output that remains active until V_CC exceeds V_TRIP for 200 ms. Its watchdog timer monitors SDA transitions during SCL HIGH and triggers reset if no valid start condition occurs within the selected timeout interval.

Internally, it combines a 16K × 8-bit EEPROM array organized in 64-byte pages with nonvolatile control register (at FFFFh) managing BP2–BP0 block lock bits and WD1–WD0 watchdog timing. Communication uses standard I²C protocol with slave address format 1010-S1-S0-R/W, supporting byte writes, page writes (up to 64 bytes), and random/sequential reads - all with built-in write cycle self-timing (~5 ms typical).

Key Specifications

Pinout & Package

Package: 8-lead SOIC (JEDEC MS-012) and 8-lead TSSOP (JEDEC MO-153), both RoHS-compliant and pin-compatible.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6900AESA+ and STM8T142M2U6, the X4283S8 uniquely balances dedicated supervision reliability, field-adjustable V_TRIP, and robust EEPROM protection - making it optimal for cost-sensitive, safety-critical systems where external MCU resources must remain unburdened.

Availability

X4283S8 is available at Aetrix Electronics and suitable for industrial PLC controllers, medical diagnostic devices, automotive body control modules, smart energy meters, and battery-powered IoT edge nodes requiring stable component supply across extended product lifecycles.

Supply support for X4283S8 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 high-reliability, low-power, and field-programmable analog-digital integration.

The X4283/85 family was designed for embedded systems requiring autonomous power supervision and tamper-resistant configuration storage - targeting applications where firmware integrity, boot reliability, and long-term data retention are mission-critical.

FAQ

What is the default reset threshold voltage of the X4283S8?

The X4283S8 ships with a factory-default V_TRIP of 2.63V. This value is nonvolatile and remains stable over temperature and time unless explicitly reprogrammed using the VP pulse sequence on the WP pin. The device supports four standard thresholds (2.63V, 2.93V, 3.08V, 4.38V), and allows fine-tuning to custom values between 1.6V and 4.65V - a capability confirmed in the X4283/85 datasheet Rev 1.21, Section "V_CC Threshold Reset Procedure".

How does the watchdog timer in the X4283S8 get triggered and reset?

The X4283S8 watchdog timer is reset by a falling edge on the SDA pin while SCL is HIGH - corresponding to a valid I²C start condition. If no such transition occurs within the selected timeout period (200 ms, 600 ms, or 1.4 s), the device asserts RESET/RESET. The timeout is set via nonvolatile WD1/WD0 bits in the control register and persists across power cycles. This behavior is documented in the "WATCHDOG TIMER" section of the X4283/85 datasheet Rev 1.21, page 3.

Can the X4283S8's EEPROM be written to while the RESET/RESET output is active?

No - the X4283S8 blocks all EEPROM write operations while RESET/RESET is active, whether due to power-up, brownout, or watchdog timeout. This is a hardware-enforced protection mechanism to prevent data corruption during unstable supply conditions. In-progress writes are allowed to complete, but new writes are rejected. This behavior is explicitly stated in the "EEPROM INADVERTENT WRITE PROTECTION" section of the X4283/85 datasheet Rev 1.21, page 3.

What package types are offered for the X4283S8, and are they pin-compatible?

The X4283S8 is available in 8-lead SOIC (JEDEC MS-012) and 8-lead TSSOP (JEDEC MO-153) packages. Both share identical pin numbering and function mapping per the "PIN CONFIGURATION" diagram on page 2 of the X4283/85 datasheet Rev 1.21. This pin compatibility enables direct PCB footprint interchangeability - critical for design flexibility and second-source strategy without layout revision.

How many bytes can be written in a single page write operation to the X4283S8's EEPROM?

The X4283S8 supports 64-byte page writes to its 128 Kbit EEPROM array. Each page is internally aligned to 64-byte boundaries, and the device automatically increments the address counter during sequential byte transmission. Writing beyond the page boundary causes wraparound (e.g., writing 12 bytes starting at offset 60 writes 4 bytes to 60–63 and 8 bytes to 0–7). This 64-byte page size and wrap behavior are specified in the "Page Write" section of the X4283/85 datasheet Rev 1.21, page 9.