Renesas X4165P-4.5A

Overview

X4165P-4.5A from Xicor (now Renesas) is a CPU supervisor IC integrating power-on reset control, watchdog timer, supply voltage supervision, and 16 Kbit serial EEPROM in a single 8-pin SOIC package. It provides selectable watchdog timeout (200 ms/600 ms/1.4 s), low-V_CC reset assertion down to 1 V, and 400 kHz I²C-compatible 2-wire interface - used in embedded microcontroller systems for reliable boot sequencing and brownout protection.

For engineers reviewing the X4165P-4.5A datasheet, X4165P-4.5A pinout, X4165P-4.5A application, or X4165P-4.5A equivalent, key selection criteria include its programmable V_TRIP threshold (factory-set at 4.5 V), open-drain active-HIGH RESET output, 2.7–5.5 V operating range, and hardware write protection via WP pin and nonvolatile BP bits.

Technical Context

The X4165P-4.5A implements a dual-function reset architecture: power-on reset with 250 ms delay and low-V_CC detection with hysteresis, where RESET remains asserted until V_CC exceeds the trip point for 200 ms. Its watchdog timer monitors SDA transitions during SCL HIGH and supports three fixed timeout intervals via nonvolatile WD1/WD0 bits.

It embeds a 2K × 8-bit EEPROM array organized in 64-byte pages, supporting byte and page writes with self-timed 5 ms typical write cycles. Communication uses standard I²C protocol (7-bit slave address 0xA0–0xA7), with SDA/SCL pins featuring open-drain outputs and active-low acknowledge signaling.

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 EEPROM applications.

Compared with MAX6816EPA+ and STM8S105K4T6C, the X4165P-4.5A delivers guaranteed EEPROM endurance (1M cycles), hardware-programmable reset threshold, and atomic watchdog/memory supervision - reducing BOM count, layout complexity, and qualification effort for safety-critical embedded systems.

Availability

X4165P-4.5A is available at Aetrix Electronics and suitable for industrial PLC controllers, medical infusion pumps, automotive body control modules, smart energy meters, and telecom power management systems requiring stable component supply, long-lifecycle support, and guaranteed EEPROM data retention.

Supply support for X4165P-4.5A 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 embedded supervision and data retention.

The X4163/5 family was designed for cost-sensitive, space-constrained microcontroller systems needing integrated reset, watchdog, voltage monitoring, and EEPROM - targeting industrial, medical, and automotive applications where board area and component count reduction are critical.

FAQ

What is the factory-set V_TRIP voltage for the X4165P-4.5A?

The X4165P-4.5A is shipped with a factory-programmed V_TRIP threshold of 4.5 V ±100 mV. This value is stored in nonvolatile circuitry and remains stable over temperature and time unless explicitly reprogrammed using the VP (12–15 V) pulse on the WP pin and the defined sequence in the datasheet. The '4.5A' suffix in the part number directly indicates this nominal trip point.

How does the X4165P-4.5A differ from the X4163 variant?

The X4165P-4.5A features an active-HIGH open-drain RESET output, whereas the X4163 uses active-LOW. Both share identical EEPROM capacity, watchdog functionality, V_TRIP programming, and pinout. The RESET polarity difference determines compatibility with MCU reset input logic - X4165P-4.5A interfaces directly with processors requiring active-HIGH reset assertion.

Can the watchdog timer on the X4165P-4.5A be disabled after power-up?

Yes, the watchdog timer on the X4165P-4.5A can be disabled after power-up by writing WD1=1 and WD0=1 to the Control Register (address FFFFh). This requires the three-step volatile latch sequence (WEL → RWEL → data write) and is nonvolatile - the setting persists across power cycles. Disabling is the factory default state.

What EEPROM write protection mechanisms does the X4165P-4.5A support?

The X4165P-4.5A supports four layered write protection mechanisms: (1) Power-on/power-down inhibition while RESET is active, (2) Software Block Lock (BP2/BP1/BP0) for 64-byte to full-array segments, (3) WP pin + WPEN bit for hardware lock, and (4) WEL/RWEL volatile latches requiring explicit enable before any register or memory write. All operate concurrently.

Is the X4165P-4.5A compatible with standard I²C bus timing?

Yes, the X4165P-4.5A is fully compatible with standard I²C bus timing at up to 400 kHz. It responds to 7-bit slave addresses 0xA0–0xA7 (determined by S0/S1 pins), supports START/STOP conditions, ACK/NACK signaling, and both byte and page write modes. No special timing deviations or protocol extensions are required for interoperability with standard I²C masters.