Renesas X4325S8I-2.7

Overview

X4325S8I-2.7 from Xicor (now Renesas) is a CPU supervisor IC integrating power-on reset control, watchdog timer, supply voltage supervision, and 32Kbit serial EEPROM in an 8-pin SOIC package. It features selectable watchdog timeout (200 ms/600 ms/1.4 s), low-V_CC reset assertion down to 1V, 400 kHz I²C interface, and programmable V_TRIP threshold - used in microcontroller-based industrial controllers for reliable boot sequencing and brownout recovery.

For engineers reviewing the X4325S8I-2.7 datasheet, X4325S8I-2.7 pinout, X4325S8I-2.7 application, or X4325S8I-2.7 equivalent, key selection criteria include its dual-role RESET/RESET output (active-low/open-drain), nonvolatile watchdog configuration, 64-byte page write capability, and hardware write protection via WP pin + WPEN bit - all critical for embedded system reliability validation.

Technical Context

The X4325S8I-2.7 implements a dedicated low-voltage detection circuit with four factory-standard V_TRIP thresholds (2.63V, 2.93V, 3.08V, 4.38V) and user-programmable adjustment via high-voltage pulse on WP pin. Its watchdog timer monitors SDA transitions during SCL HIGH and asserts RESET/RESET if no start condition occurs within the selected timeout period.

Internally, it combines a 4K × 8-bit EEPROM array with block lock protection (1–8 pages or full array), volatile WEL/RWEL latches, and nonvolatile control register (at FFFFh) storing WD1/WD0 and BP2/BP1/BP0 bits. All serial communication follows standard I²C protocol at up to 400 kHz with acknowledge polling support.

Key Specifications

Pinout & Package

Package: 8-lead JEDEC SOIC (SO-8), 150 mil width, RoHS-compliant.

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 STM8AF6266TDY, the X4325S8I-2.7 uniquely delivers field-programmable V_TRIP, hardware-enforced block-level EEPROM protection, and zero-software supervisor functionality - making it optimal for legacy MCU designs requiring drop-in reliability upgrades without firmware changes.

Availability

X4325S8I-2.7 is available at Aetrix Electronics and suitable for industrial PLC controllers, medical infusion pumps, automotive body control modules, smart energy meters, and battery-backed data loggers requiring stable component supply and long-term lifecycle support.

Supply support for X4325S8I-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 high-reliability, low-power, and system-integration features.

The X4325 product line was designed for embedded systems requiring consolidated power supervision, fault monitoring, and parameter storage - targeting applications where board space, BOM count, and functional safety are critical constraints.

FAQ

What is the factory-default V_TRIP threshold for X4325S8I-2.7?

The X4325S8I-2.7 ships with a factory-default V_TRIP threshold of 2.7V nominal, corresponding to the "-2.7" suffix in the part number. This value is laser-trimmed and remains stable over temperature and time unless reprogrammed using the high-voltage VP pulse method on the WP pin. The device supports adjustment within ±100 mV of this base value.

Does X4325S8I-2.7 support I²C multi-master arbitration?

No, the X4325S8I-2.7 operates exclusively as an I²C slave device and does not implement multi-master arbitration logic. It responds only to valid START conditions followed by its configured slave address (1010xx0). Bus contention must be managed externally by the system master controller, as the device lacks clock stretching or arbitration resolution circuitry.

Can the watchdog timer on X4325S8I-2.7 be disabled after power-up?

Yes, the watchdog timer on X4325S8I-2.7 can be disabled after power-up by writing WD1=1 and WD0=1 to the control register at address FFFFh. This setting persists in nonvolatile memory and remains active across power cycles until explicitly rewritten. Disabling the watchdog removes SDA transition monitoring but retains all other supervisor functions.

How does hardware write protection work on X4325S8I-2.7?

Hardware write protection on X4325S8I-2.7 requires both the WP pin held HIGH and the WPEN bit set to '1' in the control register. When both conditions are met, all nonvolatile writes - including EEPROM data, block lock bits, and control register fields - are blocked. This protection persists even if the WEL latch is set, providing tamper-resistant memory integrity independent of software state.

What is the maximum EEPROM write cycle time for X4325S8I-2.7?

The maximum EEPROM write cycle time for X4325S8I-2.7 is 10 ms for nonvolatile control register writes and 5 ms typical (10 ms max) for 64-byte page writes. During this time, the device ignores all I²C commands and pulls SDA high-impedance. Acknowledge polling - issuing repeated START + slave address - is the recommended method to detect write completion before initiating subsequent operations.