Renesas X4165PI

Overview

X4165PI from Xicor is a CPU supervisor IC integrating power-on reset control, selectable watchdog timer, low-V_CC voltage supervision, and 16 Kbit (2K × 8) serial EEPROM in a single 8-pin SOIC package. It asserts active-HIGH RESET during power-up, brownout, or watchdog timeout; supports 400 kHz I²C interface; operates from 2.7V to 5.5V; and delivers <1 µA standby current with watchdog disabled.

For engineers reviewing the X4165PI datasheet, X4165PI pinout, X4165PI application, or X4165PI equivalent, key selection considerations include its programmable V_TRIP threshold (adjustable via nonvolatile programming), 64-byte page write capability, Block Lock protection granularity (down to 64 bytes), and dual-reset output polarity support distinguishing it from X4163 variants.

Technical Context

The X4165PI implements a dedicated low-voltage detection circuit with four factory-standard reset thresholds (e.g., 2.63V, 2.93V, 3.08V, 4.38V), all reprogrammable to custom values between 1.0V and 5.5V using a 12–15V pulse on WP and precise V_CC biasing. Its watchdog timer uses SDA edge detection (HIGH-to-LOW while SCL is HIGH) and offers three timeout options: 200 ms, 600 ms, or 1.4 s - configured via nonvolatile WD1/WD0 bits.

Internally, the device combines a 2K × 8 EEPROM array with hardware write protection (WP pin + WPEN bit), volatile WEL/RWEL latches for register access control, and a power-on reset generator releasing RESET after 200 ms of stable V_CC. All communications occur over a standard 2-wire I²C-compatible bus with slave address 0xA0–0xA7 (determined by S0/S1 pins), supporting byte and page writes with self-timed 5 ms typical write cycles.

Key Specifications

Pinout & Package

Package: 8-lead SOIC (JEDEC MS-012), 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 MAX6816EPA+ and STMR1001MTR, the X4165PI uniquely integrates 16 Kbit EEPROM, user-programmable V_TRIP, and three selectable watchdog timeouts in a single 8-pin SOIC - reducing BOM count, PCB area, and qualification effort for embedded systems requiring both supervision and persistent configuration storage.

Availability

X4165PI is available at Aetrix Electronics and suitable for industrial PLC controllers, medical infusion pumps, smart energy meters, and automotive body control modules requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for X4165PI 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.

The X4163/5 family was designed to replace discrete reset ICs, watchdog timers, and serial EEPROMs in space-constrained embedded systems - targeting cost-sensitive, reliability-critical applications in industrial, medical, and metering markets.

FAQ

What is the key functional difference between X4165PI and X4163PI?

The X4165PI features an active-HIGH RESET output, whereas the X4163PI provides active-LOW RESET. This distinction determines compatibility with the target microcontroller's reset input polarity. Both share identical EEPROM capacity, watchdog functionality, V_TRIP programmability, and pinout - making them drop-in replacements except for reset signal interpretation.

How is the V_TRIP threshold programmed on the X4165PI?

V_TRIP programming on the X4165PI requires applying 12–15V to the WP pin while holding V_CC at the desired trip voltage, then issuing a specific two-byte I²C write sequence (0xA0h followed by 0x00h) with WEL bit previously set. The operation takes up to 10 ms and is nonvolatile - the new threshold persists across power cycles.

Does the X4165PI support standard I²C addressing and protocol?

Yes, the X4165PI fully complies with standard I²C Fast-mode (400 kHz) operation. Its 7-bit slave address is determined by S0 and S1 pins, yielding addresses 0xA0–0xA7. It supports START/STOP, ACK/NACK, byte write, page write (64-byte max), current/random/sequential reads, and acknowledge polling - all without requiring custom drivers.

What protection mechanisms prevent unintended writes to the X4165PI EEPROM?

The X4165PI employs five layered protections: (1) volatile WEL latch must be set before any write; (2) RWEL latch required for control register modification; (3) hardware WP pin + WPEN bit enable block-level write lock; (4) Block Protect bits (BP2–BP0) define protected memory regions; (5) RESET/RESET assertion disables all communication during brownout or watchdog timeout.

Can the watchdog timer on the X4165PI be disabled, and how?

Yes, the watchdog timer on the X4165PI is disabled by default (WD1=1, WD0=1). To disable it permanently, ensure the control register's WD1 and WD0 bits remain set to '11' - which prevents timeout assertion regardless of SDA activity. This state is nonvolatile and survives power cycles unless explicitly rewritten.