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

Renesas X40431S14I-B

Name: X40431S14I-B
Brand: Renesas
SKU: X40431S14I-B
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: X40431S14I-B

Manufacturer:: Renesas

Category:: Supervisors

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

Datasheet:: X40431S14I-B.pdf

Description:: IC SUPERVISOR 3 CHANNEL 14SOIC

Quantity:: RFQ Add To RFQ list

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Product details

Overview

X40431S14I-B from Xicor is a triple-voltage CPU supervisor IC with integrated 4Kbit EEPROM, active-low open-drain RESET output, and programmable voltage thresholds for V_CC (V1), V2MON, and V3MON. It provides power-on reset (t_PURST = 200 ms factory default), watchdog timer (25 ms / 200 ms / 1.4 s or off), and fault detection register - used in network storage controllers to ensure reliable boot sequencing and brownout recovery under multi-rail power conditions.

For engineers reviewing the X40431S14I-B datasheet, X40431S14I-B pinout, X40431S14I-B application, or X40431S14I-B equivalent, key selection criteria include its triple independent voltage monitoring capability (5V/3V/1.8V nominal thresholds), 400 kHz I²C-compatible 2-wire interface, Block Lock™ EEPROM protection, and manual reset debouncing - all in a 14-pin SOIC/TSSOP package.

Technical Context

The X40431S14I-B implements three independent comparator-based voltage monitors: V1 (V_CC) with reset assertion down to 1 V, V2MON powered by V2MON itself (X40431 variant), and V3MON powered by V3MON input - enabling true supply independence for secondary/tertiary rail supervision. Its watchdog logic responds to SDA/SCL activity via I²C bus protocol, requiring Start–Clock Low–Clock High–Stop sequence to reset.

Reset generation uses a programmable power-up delay (t_PURST = 50/200/400/800 ms) and supports both active-HIGH (X40430/34) and active-LOW (X40431/35) outputs; X40431S14I-B delivers active-LOW RESET via open-drain driver. The EEPROM array uses Direct Write™ cells (100,000 write cycles, 100-year data retention) with 16-byte page write mode and 5 ms typical write cycle time.

Key Specifications

Parameter	Value and Actual Design Meaning
Voltage Monitoring	Three independent rails: V_CC (V1), V2MON, V3MON - each with user-programmable trip points
RESET Output Type	Active-LOW open-drain (X40431 variant), compatible with external pull-up to any logic rail
Power Supply Range	2.7 V to 5.5 V - supports 3.3 V and 5 V systems without level-shifting
I²C Interface Speed	400 kHz maximum - enables fast configuration and EEPROM access in real-time systems
Standby Current	25 µA typical (watchdog enabled), 6 µA typical (watchdog disabled) - suitable for low-power standby modes
EEPROM Capacity	4 Kbit (512 × 8), organized in 16-byte pages - supports firmware parameter storage and calibration data
Watchdog Timeout Options	25 ms, 200 ms, 1.4 s, or disabled - selectable via nonvolatile control register bits WD1/WD0

Pinout & Package

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

Pin/Terminal	Circuit Role	Design Meaning
1 V2FAIL	Open-drain voltage fail indicator	Asserts LOW when V2MON < V_TRIP2; no power-up delay - usable for immediate power-fail interrupt
2 V2MON	Second voltage monitor input	Supplied by V2MON itself (X40431); monitors unregulated or auxiliary supply without external bias
3 LOWLINE	Early V_CC undervoltage flag	CMOS output goes LOW before RESET asserts - enables preemptive system shutdown or warning
4 NC	No connect	Not internally bonded; must be left floating or tied to ground per layout guidelines
5 MR	Debounced manual reset input	Active-LOW push-button interface with internal RC debounce - eliminates external RC network
6 RESET	Active-LOW open-drain reset output	Drives system reset line; requires external pull-up; remains active for t_PURST after release
7 V_SS	Ground reference	Primary return path for all analog comparators and digital logic; must be low-impedance
8 SDA	Serial data bidirectional I²C line	Open-drain, requires pull-up; carries EEPROM data, control register writes, and watchdog restart commands
9 SCL	Serial clock input	Master-generated clock for I²C timing; synchronizes all read/write and watchdog reset sequences
10 WP	Hardware write protect	HIGH disables all writes to EEPROM and registers - prevents accidental corruption during power transitions
11 V3MON	Third voltage monitor input	Supplied by V3MON input; monitors third rail independently of V_CC - critical for multi-supply SoC platforms
12 V3FAIL	Open-drain third-rail fail indicator	Asserts LOW when V3MON < V_TRIP3; no power-up delay - supports cascaded fault reporting
13 WDO	Watchdog timeout output	Active-LOW open-drain signal indicating MCU hang; can drive external reset or interrupt controller
14 V_CC	Main supply voltage input	2.7–5.5 V operation; powers internal logic, V1 monitor, and EEPROM interface - not used for V2MON/V3MON bias

Key Features

Feature	Design Value
Triple independent voltage supervision	Enables simultaneous monitoring of core, I/O, and auxiliary rails without shared reference or supply dependency
User-programmable V_TRIP thresholds	Allows fine-tuning of reset points via high-voltage programming sequence - avoids external resistor dividers
Fault Detection Register (FDR)	Volatile status byte (0xFF) identifies exact reset cause (LV1F/LV2F/LV3F/WDF/MRF) - accelerates root-cause analysis
Block Lock™ EEPROM protection	Nonvolatile BP bit locks upper 256 bytes (100h–1FFh) - secures bootloader or security keys against overwrite
Low-power watchdog with four intervals	Configurable timeout prevents runaway code while minimizing current draw in sleep states

Applications

Network Storage Controllers	Routers & Switches
Use Scenario: Multi-rail power sequencing in RAID controller boards with 5 V, 3.3 V, and 1.8 V supplies. IC Role / Device Role / Timing Role: Triple-voltage supervisor ensures clean boot by holding RESET until all rails stabilize; EEPROM stores board-specific configuration. Use Value: Eliminates need for three discrete supervisors and external EEPROM - reduces BOM count by ≥4 components.	Use Scenario: High-availability enterprise switch with hot-swap power modules and dual-redundant CPUs. IC Role / Device Role / Timing Role: Monitors primary 3.3 V rail (V_CC), backup 5 V management rail (V2MON), and 1.2 V PHY supply (V3MON); WDO triggers failover on primary CPU hang. Use Value: Enables autonomous failover without host intervention - improves system uptime by eliminating single-point reset dependency.
Industrial Process Controllers	Embedded Computer Systems
Use Scenario: Programmable logic controller (PLC) with isolated 24 V field power, 5 V logic, and 3.3 V FPGA core. IC Role / Device Role / Timing Role: V2MON tracks unregulated 24 V via resistor divider; V3MON monitors FPGA core voltage; LOWLINE signals early brownout to initiate graceful I/O shutdown. Use Value: Prevents corrupted I/O state during partial power loss - maintains deterministic behavior in safety-critical loops.	Use Scenario: Fanless embedded PC with Intel Atom processor, DDR3 memory, and SATA storage. IC Role / Device Role / Timing Role: Supervises 5 V main, 3.3 V PCIe, and 1.5 V DDR termination rails; EEPROM stores BIOS configuration and thermal calibration data. Use Value: Guarantees consistent boot across temperature extremes - V_TRIP reprogramming compensates for voltage drift at -40°C to +85°C.

Network Storage Controllers

Routers & Switches

Use Scenario: Multi-rail power sequencing in RAID controller boards with 5 V, 3.3 V, and 1.8 V supplies.

IC Role / Device Role / Timing Role: Triple-voltage supervisor ensures clean boot by holding RESET until all rails stabilize; EEPROM stores board-specific configuration.

Use Value: Eliminates need for three discrete supervisors and external EEPROM - reduces BOM count by ≥4 components.

Use Scenario: High-availability enterprise switch with hot-swap power modules and dual-redundant CPUs.

IC Role / Device Role / Timing Role: Monitors primary 3.3 V rail (V_CC), backup 5 V management rail (V2MON), and 1.2 V PHY supply (V3MON); WDO triggers failover on primary CPU hang.

Use Value: Enables autonomous failover without host intervention - improves system uptime by eliminating single-point reset dependency.

Industrial Process Controllers

Embedded Computer Systems

Use Scenario: Programmable logic controller (PLC) with isolated 24 V field power, 5 V logic, and 3.3 V FPGA core.

IC Role / Device Role / Timing Role: V2MON tracks unregulated 24 V via resistor divider; V3MON monitors FPGA core voltage; LOWLINE signals early brownout to initiate graceful I/O shutdown.

Use Value: Prevents corrupted I/O state during partial power loss - maintains deterministic behavior in safety-critical loops.

Use Scenario: Fanless embedded PC with Intel Atom processor, DDR3 memory, and SATA storage.

IC Role / Device Role / Timing Role: Supervises 5 V main, 3.3 V PCIe, and 1.5 V DDR termination rails; EEPROM stores BIOS configuration and thermal calibration data.

Use Value: Guarantees consistent boot across temperature extremes - V_TRIP reprogramming compensates for voltage drift at -40°C to +85°C.

Equivalent & Alternatives

The following parts are listed as comparable options for similar triple-voltage supervisor with EEPROM applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MAX6822EUK+T	Single-voltage supervisor (V_CC only); no V2MON/V3MON inputs; no EEPROM; SOT23-5 package	Lacks multi-rail monitoring and nonvolatile storage - suitable only for basic reset-only use cases	Select only if system uses only one monitored rail and external EEPROM is already present
TPS3808G33DBVR	Dual-voltage supervisor (V_CC, V_SENSE); no EEPROM; fixed 3.3 V threshold; SOT23-6 package	Supports only two rails; no programmability or memory - requires external circuitry for third-rail monitoring	Choose when cost sensitivity outweighs feature requirements and third-rail supervision is handled elsewhere

Compared with MAX6822EUK+T and TPS3808G33DBVR, the X40431S14I-B uniquely integrates triple independent voltage monitoring, programmable thresholds, watchdog timer, and 4Kbit EEPROM in one 14-pin package - reducing PCB area by >60% versus discrete solutions while enabling autonomous fault logging and configuration persistence.

Availability

X40431S14I-B is available at Aetrix Electronics and suitable for network storage, industrial automation, and embedded computing applications requiring stable component supply, long-term lifecycle support, and guaranteed traceability.

Supply support for X40431S14I-B 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 X4043x family was designed to consolidate power-on reset, voltage supervision, watchdog timing, and serial EEPROM into a single chip - targeting cost-sensitive, space-constrained embedded systems where reliability and multi-rail integrity are critical.

FAQ

What voltage thresholds does X40431S14I-B support out-of-the-box?

The X40431S14I-B ships with factory-programmed thresholds: V_TRIP1 = 4.35–4.45 V (V_CC), V_TRIP2 = 2.85–2.95 V (V2MON), and V_TRIP3 = 1.65–1.75 V (V3MON), matching the "-B" variant designation for 5 V / 3 V / 1.8 V system voltages. These values are stored in nonvolatile trim cells and remain stable over temperature and time unless reprogrammed using the high-voltage V_TRIP adjustment procedure.

Can X40431S14I-B monitor voltages below 1 V?

No - the X40431S14I-B's comparators require minimum operating headroom: V_CC must be ≥2.7 V for full functionality, and V2MON/V3MON inputs require ≥1.0 V to assert their respective FAIL outputs. While RESET remains valid down to V_CC = 1 V, the V2FAIL and V3FAIL outputs do not function below ~1.0 V due to internal comparator limitations specified in the datasheet.

How is the watchdog timer reset on X40431S14I-B?

The X40431S14I-B watchdog timer is reset by issuing a specific I²C sequence on the SDA/SCL lines: a START condition, followed by toggling SCL from HIGH to LOW, then HIGH again, and ending with a STOP condition - all while SDA remains HIGH except during START/STOP edges. This sequence must occur within the selected timeout interval (25 ms / 200 ms / 1.4 s) to prevent WDO assertion.

Does X40431S14I-B support I²C standard-mode or fast-mode?

The X40431S14I-B supports Fast-mode I²C operation up to 400 kHz, as confirmed by its AC electrical characteristics table. It is fully compatible with standard 100 kHz I²C controllers but achieves faster EEPROM configuration and status reads at 400 kHz - provided the master device and PCB layout meet rise/fall time requirements (≤300 ns).

Is the EEPROM in X40431S14I-B protected against accidental writes during power transitions?

Yes - the X40431S14I-B incorporates dual hardware and software write protection: the WP pin (active-HIGH) disables all writes when asserted, and internal power-up/power-down detection circuitry automatically inhibits writes when V_CC is outside 2.7–5.5 V. Additionally, Block Lock™ allows permanent locking of the upper 256 bytes via nonvolatile BP bit, preventing overwrite of critical firmware parameters stored in X40431S14I-B.

X40431S14I-B 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, 2.6V, 4.4V

Output:: Open Drain or Open Collector

Reset:: Active Low

Reset Timeout:: Adjustable/Selectable

Operating Temperature:: -40°C ~ 85°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 14-SOIC

X40431S14I-B FAQ

1.How can I place an order for X40431S14I-B through Aetrix?

Please submit a Request for Quotation (RFQ) for X40431S14I-B 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 X40431S14I-B reliable?

The price and inventory of X40431S14I-B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for X40431S14I-B is usually 5 days.

3.What payment methods are accepted for X40431S14I-B?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for X40431S14I-B transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for X40431S14I-B?

X40431S14I-B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your X40431S14I-B 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 X40431S14I-B?

For technical support, including X40431S14I-B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your X40431S14I-B requirements.

6.How does Aetrix verify that X40431S14I-B is sourced from the original manufacturer or authorized distributors?

All X40431S14I-B 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 X40431S14I-B meets industry standards.

7.What is the process for return or replacement of X40431S14I-B?

All X40431S14I-B units undergo pre-shipment inspection (PSI). If there is an issue with X40431S14I-B, 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 X40431S14I-B part is unused and in its original packaging.

Return procedure for X40431S14I-B:

1.Submit a request within 90 days.

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

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