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

Renesas X40421V14I-B

Name: X40421V14I-B
Brand: Renesas
SKU: X40421V14I-B
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: X40421V14I-B

Manufacturer:: Renesas

Category:: Supervisors

Package:: 14-TSSOP (0.173", 4.40mm Width)

Datasheet:: X40421V14I-B.pdf

Description:: IC SUPERVISOR 2 CHANNEL 14TSSOP

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Product details

Overview

X40421V14I-B from Xicor is a dual-voltage CPU supervisor IC with integrated 4kbit EEPROM, battery backup switch, watchdog timer, and programmable reset thresholds. It monitors V_CC (V_TRIP1 = 4.6V ±1%) and V_2MON (V_TRIP2 = 2.6V ±2%), asserts active-low RESET, delivers up to 50mA on V_OUT, and supports 400kHz I²C interface - used in network servers for power-fail-safe SRAM retention and system reset coordination.

For engineers reviewing the X40421V14I-B datasheet, X40421V14I-B pinout, X40421V14I-B application, or X40421V14I-B equivalent, key selection criteria include dual-threshold voltage monitoring accuracy, battery switchover hysteresis (±30mV), EEPROM block-lock protection, programmable power-on reset timeout (200ms default), and watchdog interval selection (25ms/200ms/1.4s/off).

Technical Context

The X40421V14I-B implements two independent voltage comparators feeding a logic-controlled reset generator, with V_TRIP1 factory-set at 4.6V and V_TRIP2 at 2.6V - both reprogrammable via I²C using high-voltage programming pulses on WDO. Its watchdog timer restarts on valid I²C START/STOP sequences on SDA/SCL, not general bus activity.

The battery switch uses internal 5Ω (V_CC-to-V_OUT) and 80Ω (V_BATT-to-V_OUT) MOSFETs with 60mV hysteresis around V_BATT ±0.03V; BATT-ON provides CMOS-level control of external PNP transistors for >50mA loads. The 4kbit EEPROM is organized as 512 × 8, supports 16-byte page writes, and features Block Lock™ protection of upper 256 bytes.

Key Specifications

Parameter	Value and Actual Design Meaning
V_TRIP1	4.6V ±1% - primary supply monitor threshold; holds RESET low until V_CC exceeds this level and stabilizes for t_PURST.
V_TRIP2	2.6V ±2% - secondary monitor threshold; drives V2FAIL low on undervoltage, usable for power-fail warning or dual-rail supervision.
RESET output	Active-low open-drain - asserted during V_CC brownout, manual reset, or watchdog timeout; remains active for programmed t_PURST (200ms default).
V_OUT drive	5–50mA from V_CC; 250µA from V_BATT - powers SRAM during main supply failure; switchover controlled by internal comparator with 60mV hysteresis.
EEPROM capacity	4kbit (512 × 8) - supports 16-byte page writes; 5ms typical write cycle; Block Lock™ protects upper 256 bytes from accidental overwrite.
I²C interface	400kHz max clock rate - compatible with standard Fast-mode I²C; uses slave address A0h; supports special preamble (1011) for control register access.
Watchdog timeout	Selectable: 25ms / 200ms / 1.4s / off - configured via nonvolatile WD1/WD0 bits; restarts only on valid START→SCL low→SCL high→STOP sequence.

Pinout & Package

Package: 14-lead SOIC (width 3.9mm) and TSSOP - RoHS-compliant, JEDEC MS-012AC / MO-153 compliant.

Pin/Terminal	Circuit Role	Design Meaning
1 V2FAIL	Open-drain fail indicator	Asserts LOW when V2MON < V_TRIP2; no power-up delay; requires external pull-up for logic HIGH.
2 V2MON	Secondary voltage input	Monitors unregulated rail or second supply; internally biased from V_OUT; connect to V_SS or V_CC if unused.
3 LOWLINE	Early V_CC undervoltage flag	Open-drain output active LOW when V_CC < V_TRIP1; used for preemptive system shutdown before full reset.
4 WDO	Watchdog timeout signal	Active-low open-drain output; driven LOW on watchdog expiration; also used as programming voltage input for V_TRIP adjustment.
5 MR	Debounced manual reset	Pull LOW to assert RESET; internal weak pull-up eliminates external resistor; reset duration includes t_PURST after release.
6 RESET	Primary reset output	Active-low open-drain - asserted on V_CC brownout, MR activation, or watchdog timeout; timing controlled by PUP1/PUP0 bits.
7 V_SS	Ground reference	System ground return; must be connected directly to PCB ground plane with low-inductance path.
8 SDA	I²C bidirectional data	Open-drain I²C data line; requires external pull-up; accepts START/STOP for watchdog reset; always enabled (no gating).
9 SCL	I²C clock input	Master-generated clock; sampled on rising edge for command decoding; used with SDA to restart watchdog timer.
10 WP	Hardware write protect	High = all writes blocked (EEPROM + registers); internal 10MΩ pull-down; overrides software write-enable latches.
11 V_BATT	Backup supply input	Connect to coin cell or supercap; powers internal logic and V_OUT during V_CC failure; tie to GND if unused.
12 V_OUT	System backup output	Switches between V_CC and V_BATT based on comparator decision; requires 0.1µF capacitor for stability.
13 BATT-ON	Battery-active status	CMOS output HIGH when V_OUT = V_BATT; drives external PNP transistor for high-current V_OUT delivery during normal operation.
14 V_CC	Main supply input	2.7–5.5V operating range; powers all circuitry except EEPROM write cycles (which use charge pump); resets internal logic on power-up.

Key Features

Feature	Design Value
Dual programmable voltage thresholds	V_TRIP1 and V_TRIP2 adjustable via I²C + WDO high-voltage pulse - enables fine-tuning for precision power sequencing without external resistors.
Battery-backed V_OUT with hysteresis	Automatic switchover between V_CC and V_BATT with ±30mV hysteresis prevents oscillation near threshold; supports SRAM data retention during AC loss.
Nonvolatile control register	Stores watchdog interval (WD1/WD0), power-on reset delay (PUP1/PUP0), and block lock (BP) settings across power cycles - eliminates boot-time configuration.
Fault Detection Register (FDR)	Volatile 8-bit register (address 0FFh) captures cause of last reset - LV1F, LV2F, WDF, MRF bits indicate which event triggered RESET assertion.
Block Lock™ EEPROM protection	Hardware-enforced write protection of upper 256 bytes (100h–1FFh); activated by BP bit; prevents corruption of critical firmware or calibration data.

Applications

Network Server Power Management	Disk Array Controller Supervision
Use Scenario: Maintains SRAM contents and triggers orderly shutdown during AC mains interruption or PSU fault in 1U/2U rack servers. IC Role / Device Role / Timing Role: Dual-voltage supervisor asserts RESET on V_CC brownout while switching V_OUT to V_BATT to sustain SRAM; V2FAIL warns of auxiliary rail failure. Use Value: Prevents data loss in cache memory and ensures BIOS/firmware integrity during unexpected power events.	Use Scenario: Monitors primary 5V and secondary 3.3V rails in RAID controller boards, coordinating reset sequencing between FPGA, CPU, and storage PHYs. IC Role / Device Role / Timing Role: X40421V14I-B generates synchronized RESET with 200ms t_PURST, validates both supplies pre-boot, and logs fault source in FDR for diagnostics. Use Value: Eliminates need for discrete supervisors and RC timers, reducing BOM count and improving mean time between failures (MTBF).
Industrial PLC CPU Module	Telecom Router System Monitor
Use Scenario: Ensures deterministic startup and runtime supervision in programmable logic controller CPU modules exposed to wide ambient temperature and voltage fluctuations. IC Role / Device Role / Timing Role: Uses programmable V_TRIP2 to track isolated 24V field bus supply; LOWLINE initiates graceful I/O deactivation before full RESET assertion. Use Value: Enables safe fieldbus disconnection and prevents spurious relay actuation during brownout conditions.	Use Scenario: Provides fail-safe reset coordination and SRAM backup in carrier-grade edge routers handling 10Gbps packet forwarding. IC Role / Device Role / Timing Role: X40421V14I-B watches 12V DC-DC output (V_CC) and -48V telecom supply (via resistor divider on V2MON); BATT-ON drives external pass transistor for high-current V_OUT. Use Value: Guarantees uninterrupted control-plane operation during brief power dips and supports hot-swap PSU replacement.

Network Server Power Management

Disk Array Controller Supervision

Use Scenario: Maintains SRAM contents and triggers orderly shutdown during AC mains interruption or PSU fault in 1U/2U rack servers.

IC Role / Device Role / Timing Role: Dual-voltage supervisor asserts RESET on V_CC brownout while switching V_OUT to V_BATT to sustain SRAM; V2FAIL warns of auxiliary rail failure.

Use Value: Prevents data loss in cache memory and ensures BIOS/firmware integrity during unexpected power events.

Use Scenario: Monitors primary 5V and secondary 3.3V rails in RAID controller boards, coordinating reset sequencing between FPGA, CPU, and storage PHYs.

IC Role / Device Role / Timing Role: X40421V14I-B generates synchronized RESET with 200ms t_PURST, validates both supplies pre-boot, and logs fault source in FDR for diagnostics.

Use Value: Eliminates need for discrete supervisors and RC timers, reducing BOM count and improving mean time between failures (MTBF).

Industrial PLC CPU Module

Telecom Router System Monitor

Use Scenario: Ensures deterministic startup and runtime supervision in programmable logic controller CPU modules exposed to wide ambient temperature and voltage fluctuations.

IC Role / Device Role / Timing Role: Uses programmable V_TRIP2 to track isolated 24V field bus supply; LOWLINE initiates graceful I/O deactivation before full RESET assertion.

Use Value: Enables safe fieldbus disconnection and prevents spurious relay actuation during brownout conditions.

Use Scenario: Provides fail-safe reset coordination and SRAM backup in carrier-grade edge routers handling 10Gbps packet forwarding.

IC Role / Device Role / Timing Role: X40421V14I-B watches 12V DC-DC output (V_CC) and -48V telecom supply (via resistor divider on V2MON); BATT-ON drives external pass transistor for high-current V_OUT.

Use Value: Guarantees uninterrupted control-plane operation during brief power dips and supports hot-swap PSU replacement.

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 2.9V reset threshold; no secondary voltage monitor; no battery switch; 256-byte EEPROM; 100kHz I²C.	Lacks dual-supply monitoring and V_OUT/BATT-ON functionality - suitable only for basic reset-only systems without backup power requirements.	Select MAX6361KA29+T only when supervising one rail and SRAM backup is handled externally.
TPS3808G18DBVR	Dual threshold (adjustable via external resistors); no EEPROM; no battery switch; push-pull RESET; 2.5–6V operation.	Requires external components for V_TRIP setting and separate EEPROM/Battery management IC - increases board area and design complexity.	Choose TPS3808G18DBVR when higher accuracy (±0.5%) and lower quiescent current (1.5µA) are prioritized over integration.

Compared with MAX6361KA29+T and TPS3808G18DBVR, the X40421V14I-B uniquely integrates dual-voltage supervision, battery-backed V_OUT, and 4kbit EEPROM in a single 14-pin package - reducing component count by ≥4 devices and eliminating external resistor networks for threshold tuning.

Availability

X40421V14I-B is available at Aetrix Electronics and suitable for network servers, disk array controllers, and industrial PLCs requiring stable component supply, long-lifecycle support, and guaranteed traceable sourcing.

Supply support for X40421V14I-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 X40420/X40421 family was designed to consolidate power-on reset, watchdog, dual-voltage monitoring, battery backup switching, and serial EEPROM into one device - targeting cost-sensitive, space-constrained embedded systems in communications and industrial markets.

FAQ

What is the factory-default power-on reset timeout for X40421V14I-B?

The X40421V14I-B ships with t_PURST set to 200ms by default, controlled by PUP1/PUP0 bits (01 binary) in the nonvolatile control register. This value can be changed to 50ms, 400ms, or 800ms via I²C write to address 1FFh after enabling WEL and RWEL latches - no hardware modification required.

Does X40421V14I-B support true hardware write protection independent of software state?

Yes. X40421V14I-B includes a dedicated WP pin with internal 10MΩ pull-down resistor. When WP is driven HIGH, all writes to EEPROM and control registers are blocked - including those attempted after WEL/RWEL enable - providing unconditional hardware-level protection against accidental or malicious overwrite.

How does the battery switchover hysteresis work in X40421V14I-B?

X40421V14I-B uses ±30mV hysteresis around V_BATT ±0.03V to prevent oscillation during switchover: V_OUT switches from V_CC to V_BATT when V_CC falls below V_BATT – 0.03V, and switches back to V_CC only when V_CC rises above V_BATT + 0.03V - ensuring stable output during marginal supply transitions.

Can V_TRIP2 on X40421V14I-B be programmed below 1.6V?

Yes. While the standard -B suffix specifies 2.6V for V_TRIP2, the X40421V14I-B allows V_TRIP2 programming down to 0.9V using the high-voltage programming sequence on WDO. This requires applying the target voltage to V2MON, pulsing WDO to V_PP, then issuing the I²C write command - verified by observing V2FAIL transition point.

What is the maximum continuous current X40421V14I-B can deliver from V_BATT to V_OUT?

X40421V14I-B delivers up to 250µA continuously from V_BATT to V_OUT in backup mode. This is sufficient to maintain data in typical low-leakage SRAM (e.g., Cypress CY62167EV30) for >72 hours on a CR2032 coin cell, assuming 100nA standby current per 256Kbit SRAM.

X40421V14I-B Specifications

Product attributes: Attribute value

Manufacturer:: Renesas

Series:: -

Package/Case:: 14-TSSOP (0.173", 4.40mm Width)

Packaging:: Bulk

Product Status:: Obsolete

Programmable:: Not Verified

Type:: Multi-Voltage Supervisor

Number of Voltages Monitored:: 2

Voltage - Threshold:: 2.6V, 4.6V

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-TSSOP

X40421V14I-B FAQ

1.How can I place an order for X40421V14I-B through Aetrix?

Please submit a Request for Quotation (RFQ) for X40421V14I-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 X40421V14I-B reliable?

The price and inventory of X40421V14I-B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for X40421V14I-B is usually 5 days.

3.What payment methods are accepted for X40421V14I-B?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for X40421V14I-B transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for X40421V14I-B?

X40421V14I-B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your X40421V14I-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 X40421V14I-B?

For technical support, including X40421V14I-B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your X40421V14I-B requirements.

6.How does Aetrix verify that X40421V14I-B is sourced from the original manufacturer or authorized distributors?

All X40421V14I-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 X40421V14I-B meets industry standards.

7.What is the process for return or replacement of X40421V14I-B?

All X40421V14I-B units undergo pre-shipment inspection (PSI). If there is an issue with X40421V14I-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 X40421V14I-B part is unused and in its original packaging.

Return procedure for X40421V14I-B:

1.Submit a request within 90 days.

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

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