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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Supervisors

Renesas X40431S14-A

Name: X40431S14-A
Brand: Renesas
SKU: X40431S14-A
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: X40431S14-A

Manufacturer:: Renesas

Category:: Supervisors

Package:: 14-SOIC (0.154", 3.90mm Width)

Datasheet:: X40431S14-A.pdf

Description:: IC SUPERVISOR 3 CHANNEL 14SOIC

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Product details

Overview

X40431S14-A from Xicor (now Renesas) is a triple-voltage CPU supervisor IC with integrated 4Kbit EEPROM, watchdog timer, and fault detection register. It monitors V_CC (V1), V2MON, and V3MON at factory-programmed thresholds (4.55–4.65 V, 2.95–3.05 V, 1.65–1.75 V), asserts active-low RESET and WDO outputs, and operates from 2.7 V to 5.5 V. It serves in embedded communication equipment for power-fail warning and secure boot integrity.

For engineers reviewing the X40431S14-A datasheet, X40431S14-A pinout, X40431S14-A application, or X40431S14-A equivalent, key selection criteria include triple independent voltage monitoring capability, programmable reset timeout (50/200/400/800 ms), selectable watchdog intervals (25 ms / 200 ms / 1.4 s / off), 400 kHz I²C interface, and Block Lock™ EEPROM protection - all in a 14-pin SOIC/TSSOP package.

Technical Context

The X40431S14-A implements three independent comparator-based voltage monitors with open-drain fail outputs (V2FAIL, V3FAIL) and a CMOS LOWLINE signal for early V_CC undervoltage detection. Its reset generation logic supports both power-on and brownout conditions down to V_CC = 1 V, with reset assertion held for a user-selectable t_PURST delay.

Watchdog functionality is triggered by SDA/SCL activity on the I²C bus, requiring a Start–Clock Low–Clock High–Stop sequence to reset the timer. The nonvolatile control register configures WD1/WD0 (watchdog interval), PUP1/PUP0 (reset timeout), and BP (EEPROM block lock), with write enable latched via WEL/RWEL protocol.

Key Specifications

Parameter	Value and Actual Design Meaning
V_TRIP1	4.55–4.65 V: Factory-set primary supply monitor threshold for 5 V systems; ensures reliable reset before microcontroller execution.
V_TRIP2	2.95–3.05 V: Factory-set secondary monitor threshold for 3 V/3.3 V rails; enables independent unregulated supply tracking.
V_TRIP3	1.65–1.75 V: Factory-set tertiary monitor threshold for 1.8 V core supplies; supports low-voltage SoC power sequencing.
t_PURST	Selectable 50/200/400/800 ms: Configurable power-on reset hold time prevents premature processor startup during supply ramp-up.
Watchdog Interval	25 ms / 200 ms / 1.4 s / off: Nonvolatile selection determines maximum allowed microcontroller response window before WDO assertion.
I²C Interface	400 kHz max: Full-speed I²C compatibility enables direct connection to standard microcontroller peripherals without clock stretching.
EEPROM Endurance	100,000 write cycles: Guaranteed minimum rewrite count for critical configuration or calibration data storage.
Standby Current	6 µA (WD off) / 25 µA (WD on): Ultra-low quiescent current preserves battery life in always-on supervisory applications.

Pinout & Package

Package: 14-lead SOIC (Small Outline Integrated Circuit) and TSSOP (Thin Shrink Small Outline Package), both RoHS-compliant and lead-free.

Pin/Terminal	Circuit Role	Design Meaning
1 V2FAIL	Open-drain voltage fail output	Asserts LOW when V2MON < V_TRIP2; used for interrupt or OR'd reset signaling without external pull-up dependency.
2 V2MON	Secondary voltage monitor input	Accepts 0.9–4.75 V input; comparator powered internally (X40431), enabling monitoring even if V_CC fails.
3 LOWLINE	Early V_CC undervoltage indicator	CMOS output goes LOW before RESET; provides preemptive warning for FPGA reconfiguration or graceful shutdown.
4 NC	No connect	Unbonded pin; must remain floating per datasheet; no PCB trace or pad required.
5 MR	Debounced manual reset input	Active-low pushbutton interface; internal debounce eliminates external RC network and reduces BOM count.
6 RESET	Active-low open-drain reset output	Drives system reset line; requires external pull-up; remains asserted until V_CC exceeds V_TRIP1 + t_PURST.
7 V_SS	Ground reference	Primary return path for all analog comparators, digital logic, and EEPROM core; must be low-impedance.
8 SDA	Serial data bidirectional I²C line	Open-drain interface with always-active input buffer; supports multi-master arbitration and EEPROM read/write operations.
9 SCL	Serial clock input	Master-generated clock synchronizes all I²C transactions; timing compliant with standard-mode and fast-mode specifications.
10 WP	Hardware write protect input	High-level assertion blocks all EEPROM and register writes; internal 10 MΩ pull-down ensures default unprotected state.
11 V3MON	Tertiary voltage monitor input	Accepts 0.9–4.75 V; comparator powered directly from V3MON pin, allowing monitoring of isolated supplies.
12 V3FAIL	Open-drain voltage fail output	Asserts LOW when V3MON < V_TRIP3; supports cascaded power-fail interrupts or independent reset generation.
13 WDO	Watchdog timeout output	Active-low open-drain signal indicating microcontroller hang; can drive reset logic or status LED directly.
14 V_CC	Supply voltage input	2.7–5.5 V operating range powers digital logic, EEPROM, and V1 monitor; powers V2/V3 comparators only in X40434/35 variants.

Key Features

Feature	Design Value
Triple independent voltage monitoring	Simultaneous supervision of V_CC, V2MON, and V3MON with separate fail outputs enables robust multi-rail power sequencing in routers and servers.
Programmable reset timeout (t_PURST)	Four factory-selectable delays (50/200/400/800 ms) allow precise alignment with FPGA configuration time or oscillator stabilization requirements.
Block Lock™ EEPROM protection	Configurable lock of upper 256-byte half or full array prevents accidental overwrite of critical firmware parameters or security keys.
Reprogrammable voltage thresholds	V_TRIP1/V_TRIP2/V_TRIP3 can be adjusted via high-voltage programming sequence to meet custom system tolerances without hardware changes.
Fault Detection Register (FDR)	Volatile 8-bit register captures root cause of last reset (LV1F/LV2F/LV3F/WDF/MRF), enabling automated diagnostics and field failure analysis.
Low-power watchdog operation	25 µA typical standby current with watchdog enabled allows continuous supervision in battery-backed industrial controllers.

Applications

Routers & Network Switches	Disk Arrays & Network Storage
Use Scenario: Monitoring 5 V main, 3.3 V I/O, and 1.8 V CPU core rails during hot-swap and thermal throttling events. IC Role / Device Role / Timing Role: Triple-voltage supervisor asserting RESET and WDO to halt processor execution and trigger firmware recovery before data corruption occurs. Use Value: Prevents inconsistent state in packet forwarding engines by ensuring all power domains stabilize before boot code executes.	Use Scenario: Detecting early voltage sag on 12 V spindle motor supply and 3.3 V controller rail during RAID rebuild under load. IC Role / Device Role / Timing Role: Using V2FAIL/V3FAIL as independent interrupt sources to initiate cache flush and safe spin-down before hard drive failure. Use Value: Extends drive lifetime and avoids silent data corruption by enabling predictive power management based on real-time rail margining.
Industrial Process Controllers	Embedded Servers & Blade Systems
Use Scenario: Supervising isolated 24 V fieldbus, 5 V logic, and 1.2 V FPGA core supplies in PLC backplanes with wide ambient temperature swings. IC Role / Device Role / Timing Role: Providing debounced MR input and LOWLINE early-warning signal to coordinate deterministic fail-safe transitions in safety-critical loops. Use Value: Meets SIL-2 functional safety requirements by eliminating external reset components and reducing single-point failure modes.	Use Scenario: Managing power sequencing across dual 5 V/3.3 V server management controllers and BMC firmware partitions. IC Role / Device Role / Timing Role: Storing secure boot keys in Block Lock™-protected EEPROM while using FDR to log reset causes for remote diagnostics. Use Value: Enables zero-touch provisioning and audit-ready event logging without adding discrete security ICs or FRAM.

Routers & Network Switches

Disk Arrays & Network Storage

Use Scenario: Monitoring 5 V main, 3.3 V I/O, and 1.8 V CPU core rails during hot-swap and thermal throttling events.

IC Role / Device Role / Timing Role: Triple-voltage supervisor asserting RESET and WDO to halt processor execution and trigger firmware recovery before data corruption occurs.

Use Value: Prevents inconsistent state in packet forwarding engines by ensuring all power domains stabilize before boot code executes.

Use Scenario: Detecting early voltage sag on 12 V spindle motor supply and 3.3 V controller rail during RAID rebuild under load.

IC Role / Device Role / Timing Role: Using V2FAIL/V3FAIL as independent interrupt sources to initiate cache flush and safe spin-down before hard drive failure.

Use Value: Extends drive lifetime and avoids silent data corruption by enabling predictive power management based on real-time rail margining.

Industrial Process Controllers

Embedded Servers & Blade Systems

Use Scenario: Supervising isolated 24 V fieldbus, 5 V logic, and 1.2 V FPGA core supplies in PLC backplanes with wide ambient temperature swings.

IC Role / Device Role / Timing Role: Providing debounced MR input and LOWLINE early-warning signal to coordinate deterministic fail-safe transitions in safety-critical loops.

Use Value: Meets SIL-2 functional safety requirements by eliminating external reset components and reducing single-point failure modes.

Use Scenario: Managing power sequencing across dual 5 V/3.3 V server management controllers and BMC firmware partitions.

IC Role / Device Role / Timing Role: Storing secure boot keys in Block Lock™-protected EEPROM while using FDR to log reset causes for remote diagnostics.

Use Value: Enables zero-touch provisioning and audit-ready event logging without adding discrete security ICs or FRAM.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MAX6361KA29+T	Single-voltage supervisor (2.93 V), no EEPROM, no V2/V3 monitoring, 1.6 µA standby current	Lacks triple monitoring and nonvolatile storage; suitable only for basic reset-only use cases	Select only when cost sensitivity outweighs need for multi-rail visibility and configuration retention
TPS3808G18DBVR	Dual-voltage supervisor (1.8 V / adjustable), no EEPROM, no watchdog, 12 µA standby current	Supports one adjustable threshold but omits tertiary monitoring and memory; requires external I²C EEPROM for parameter storage	Choose when system already includes separate EEPROM and only two supply rails require supervision

Compared with MAX6361KA29+T and TPS3808G18DBVR, the X40431S14-A uniquely integrates triple-voltage monitoring, programmable reset timing, watchdog, and protected EEPROM in one die - eliminating four discrete components and reducing PCB area by >35% in multi-rail embedded systems.

Availability

X40431S14-A is available at Aetrix Electronics and suitable for communication equipment, industrial process controllers, and embedded servers requiring stable component supply across extended product lifecycles.

Supply support for X40431S14-A 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 2002.

The X4043x family was designed to consolidate power-on reset, watchdog, multi-rail voltage supervision, and secure EEPROM into a single package for space-constrained networking and industrial control systems.

FAQ

What voltage thresholds are factory-programmed in the X40431S14-A?

The X40431S14-A ships with V_TRIP1 = 4.55–4.65 V (for 5 V systems), V_TRIP2 = 2.95–3.05 V (for 3 V/3.3 V rails), and V_TRIP3 = 1.65–1.75 V (for 1.8 V cores). These values are laser-trimmed during final test and remain stable over temperature and time unless reprogrammed using the high-voltage VTRIPx procedure defined in the X40431S14-A datasheet.

Does the X40431S14-A support I²C communication at 400 kHz?

Yes, the X40431S14-A supports standard-mode and fast-mode I²C up to 400 kHz. Its SDA and SCL pins comply with I²C bus electrical specifications, including open-drain outputs, slew-rate control, and acknowledge timing - enabling direct interfacing with microcontrollers such as ARM Cortex-M series without level shifters or bus buffers.

How is EEPROM write protection implemented in the X40431S14-A?

The X40431S14-A uses dual-layer EEPROM protection: hardware WP pin assertion (HIGH disables all writes) and software-configurable Block Protect (BP) bit in the nonvolatile control register. When BP = 1, the upper 256-byte half (addresses 0x100–0x1FF) is locked; BP = 0 leaves entire 4Kbit array writable. Both mechanisms must be satisfied for a write to succeed.

Can the X40431S14-A monitor voltages independently of its own V_CC supply?

Yes - the V2MON and V3MON comparators in the X40431S14-A are powered directly from their respective input pins, not from V_CC. This allows V2FAIL and V3FAIL to remain functional even if V_CC drops to 0 V, enabling true independent monitoring of auxiliary or isolated power rails - a key distinction from X40434/X40435 variants where V2/V3 comparators depend on V_CC.

What is the purpose of the Fault Detection Register (FDR) in the X40431S14-A?

The Fault Detection Register (FDR) in the X40431S14-A is a volatile 8-bit register (address 0xFF) that records the cause of the most recent system reset. Bits LV1F, LV2F, LV3F, WDF, and MRF clear to '0' when their corresponding fault condition occurs. Reading the FDR after reset allows firmware to distinguish between power failure, watchdog timeout, or manual reset - enabling targeted recovery routines in the X40431S14-A's host system.

X40431S14-A Specifications

Product attributes: Attribute value

Manufacturer:: Renesas

Series:: -

Package/Case:: 14-SOIC (0.154", 3.90mm Width)

Packaging:: Bulk

Product Status:: Obsolete

Programmable:: Not Verified

Type:: Multi-Voltage Supervisor

Number of Voltages Monitored:: 3

Voltage - Threshold:: 1.7V, 2.9V, 4.6V

Output:: Open Drain or Open Collector

Reset:: Active Low

Reset Timeout:: Adjustable/Selectable

Operating Temperature:: 0°C ~ 70°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 14-SOIC

X40431S14-A FAQ

1.How can I place an order for X40431S14-A through Aetrix?

Please submit a Request for Quotation (RFQ) for X40431S14-A on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for X40431S14-A reliable?

The price and inventory of X40431S14-A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for X40431S14-A is usually 5 days.

3.What payment methods are accepted for X40431S14-A?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for X40431S14-A transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for X40431S14-A?

X40431S14-A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your X40431S14-A order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for X40431S14-A?

For technical support, including X40431S14-A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your X40431S14-A requirements.

6.How does Aetrix verify that X40431S14-A is sourced from the original manufacturer or authorized distributors?

All X40431S14-A products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that X40431S14-A meets industry standards.

7.What is the process for return or replacement of X40431S14-A?

All X40431S14-A units undergo pre-shipment inspection (PSI). If there is an issue with X40431S14-A, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The X40431S14-A part is unused and in its original packaging.

Return procedure for X40431S14-A:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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