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

Renesas X40420S14I-B

Name: X40420S14I-B
Brand: Renesas
SKU: X40420S14I-B
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: X40420S14I-B

Manufacturer:: Renesas

Category:: Supervisors

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

Datasheet:: X40420S14I-B.pdf

Description:: IC SUPERVISOR 2 CHANNEL 14SOIC

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Product details

Overview

X40420S14I-B from Xicor (now part of Renesas) is a dual-voltage supervisor IC with integrated 4kbit EEPROM, watchdog timer, manual reset input, and battery-switched V_OUT. It provides power-on reset (t_PURST = 200ms default), dual threshold monitoring (V_TRIP1 = 4.6V ±1%, V_TRIP2 = 2.6V ±2%), and 5mA–50mA system backup switching - used in industrial controllers and network servers for brownout protection and SRAM retention.

For engineers reviewing the X40420S14I-B datasheet, X40420S14I-B pinout, X40420S14I-B application, or X40420S14I-B equivalent, key selection criteria include its dual-supply fail detection logic, programmable V_TRIP2 down to 0.9V, 400kHz I²C interface, 25µA standby current (watchdog on), and 14-pin SOIC/TSSOP package compatibility.

Technical Context

The X40420S14I-B implements two independent voltage comparators: one monitors V_CC against fixed 4.6V V_TRIP1, the other monitors V_2MON against factory-set 2.6V V_TRIP2 (reprogrammable to 0.9V). Its reset output is active-HIGH open-drain (X40420 variant), asserted during V_CC < V_TRIP1 or MR assertion, with t_PURST configurable to 50/200/400/800ms.

It integrates a watchdog timer triggered by I²C activity (SDA/SCL transitions), with timeout options of 25ms/200ms/1.4s or disabled; a battery switch that routes V_OUT to V_BATT when V_CC drops below V_TRIP1 and V_BATT – 0.03V; and 4kbit Block Lock™ EEPROM organized as 512 × 8, accessible via 2-wire interface at up to 400kHz.

Key Specifications

Parameter	Value and Actual Design Meaning
V_TRIP1	4.6V ±1% - primary supply monitor threshold; asserts RESET when V_CC falls below this level.
V_TRIP2	2.6V ±2% - secondary monitor threshold (suffix -B); programmable down to 0.9V for custom power-fail warning.
t_PURST	200ms default - power-on reset timeout; selectable via nonvolatile control bits (50/200/400/800ms).
Watchdog timeout	200ms default - factory-disabled; enabled via WD1/WD0 bits; restarts on valid I²C START/STOP sequence.
EEPROM capacity	4kbit (512 × 8) - supports 16-byte page writes; 5ms typical write cycle; 100,000 endurance cycles.
V_OUT drive capability	50mA from V_CC, 250µA from V_BATT - powers external SRAM during main supply failure with hysteresis-controlled switchover.
Supply range	2.7V to 5.5V - operates across standard 3.3V and 5V logic rails; RESET remains valid down to V_CC = 1V.

Pinout & Package

Package: 14-lead SOIC (Small Outline Integrated Circuit) and TSSOP (Thin Shrink Small Outline Package), both RoHS-compliant, 1.27mm pitch, body width 3.9mm (SOIC) / 4.4mm (TSSOP).

Pin/Terminal	Circuit Role	Design Meaning
1 V2FAIL	Open-drain fail indicator	Active-LOW signal indicating V_2MON < V_TRIP2; no power-up delay; requires external pull-up.
2 V2MON	Secondary voltage monitor input	Accepts unregulated or second supply; threshold set to 2.6V (X40420S14I-B); programmable via I²C sequence.
3 LOWLINE	Early low-V_CC detect output	Open-drain active-LOW signal when V_CC < V_TRIP1; used for preemptive brownout warning.
4 WDO	Watchdog timeout output	Active-LOW open-drain output; asserts when watchdog timer expires; used to trigger system recovery.
5 MR	Manual reset input	Debounced active-LOW input; internal pull-up; initiates reset pulse lasting t_PURST.
6 RESET	Active-HIGH reset output (X40420)	Open-drain active-HIGH output; asserted during V_CC undervoltage or MR event; holds for t_PURST.
7 V_SS	Ground reference	Primary ground connection; must be connected to system common ground plane.
8 SDA	I²C bidirectional data line	Open-drain serial data; supports 400kHz operation; used for EEPROM access and configuration register reads/writes.
9 SCL	I²C clock input	Input-only clock line; controls timing of all serial transfers; requires external pull-up.
10 WP	Write protect enable	Active-HIGH input; disables all writes (EEPROM and registers) when pulled HIGH; internal pull-down (~10MΩ).
11 V_BATT	Battery backup supply input	Provides backup power source; connects to V_OUT when V_CC fails; connect to ground if unused.
12 V_OUT	System backup output	Switched output sourcing 50mA from V_CC or 250µA from V_BATT; powers SRAM during power loss.
13 BATT-ON	Battery active status indicator	CMOS output HIGH when V_OUT is sourced from V_BATT; drives external PNP transistor for higher-current operation.
14 V_CC	Main supply input	Primary power rail (2.7–5.5V); powers all internal circuits except EEPROM during write cycles.

Key Features

Feature	Design Value
Dual independent voltage supervision	Simultaneous monitoring of V_CC and V_2MON enables early power-fail detection and redundant system safety checks.
Programmable V_TRIP2 threshold	Adjustable from factory 2.6V down to 0.9V using I²C command sequence - eliminates need for external resistor dividers in precision applications.
Integrated battery-switched V_OUT	Automatically switches to V_BATT with 60mV hysteresis when V_CC drops below V_TRIP1 and V_BATT – 0.03V - ensures clean SRAM retention without external MOSFETs.
Nonvolatile control register	Stores t_PURST, watchdog timeout, and block-lock settings across power cycles - enables field-configurable behavior without firmware changes.
Block Lock™ EEPROM protection	Hardware-enforced write protection for upper 256 bytes (BP = 1) or full array (BP = 0) - prevents accidental corruption of critical configuration data.
Low-power standby operation	6µA typical current with watchdog disabled - suitable for battery-backed systems requiring multi-year shelf life.

Applications

Industrial Process Controller	Network Router Power Management
Use Scenario: PLCs and distributed I/O modules operating in harsh environments with fluctuating 24V DC supplies converted to 5V/3.3V rails. IC Role / Device Role / Timing Role: Dual-voltage supervisor monitors both regulated 5V logic rail and auxiliary 3.3V I/O rail; asserts RESET on either undervoltage to halt CPU execution before data corruption. Use Value: Prevents spurious state transitions during brownouts; preserves SRAM contents via V_OUT/V_BATT switchover; eliminates need for discrete supervisors and backup diodes.	Use Scenario: Carrier-grade routers with hot-swappable line cards requiring deterministic power sequencing and fail-safe memory retention. IC Role / Device Role / Timing Role: Monitors primary 5V supply (V_TRIP1) and unregulated 12V intermediate bus (V_2MON via resistor divider); triggers V2FAIL interrupt for predictive power-fail handling. Use Value: Enables graceful shutdown of packet buffers; maintains MAC address tables in SRAM during brief AC outages; reduces MTTR via fault detection register logging.
Desktop Motherboard BIOS Protection	Medical Diagnostic Equipment
Use Scenario: ATX motherboards where CMOS real-time clock and BIOS configuration must survive AC power loss. IC Role / Device Role / Timing Role: Provides power-on reset with 200ms t_PURST, monitors +5VSB standby rail, and backs up RTC SRAM via V_BATT input from coin cell. Use Value: Guarantees reliable boot initialization after cold start; prevents BIOS corruption during sudden power loss; simplifies layout with single-chip solution.	Use Scenario: Portable ultrasound devices with lithium battery backup and strict IEC 60601-1 power integrity requirements. IC Role / Device Role / Timing Role: Supervises main 3.3V system rail and battery voltage; uses watchdog to detect firmware hangs; stores calibration data in protected EEPROM. Use Value: Ensures patient data persistence during battery swaps; meets Class BF isolation requirements via galvanically isolated reset signaling; supports audit-trail logging in nonvolatile memory.

Industrial Process Controller

Network Router Power Management

Use Scenario: PLCs and distributed I/O modules operating in harsh environments with fluctuating 24V DC supplies converted to 5V/3.3V rails.

IC Role / Device Role / Timing Role: Dual-voltage supervisor monitors both regulated 5V logic rail and auxiliary 3.3V I/O rail; asserts RESET on either undervoltage to halt CPU execution before data corruption.

Use Value: Prevents spurious state transitions during brownouts; preserves SRAM contents via V_OUT/V_BATT switchover; eliminates need for discrete supervisors and backup diodes.

Use Scenario: Carrier-grade routers with hot-swappable line cards requiring deterministic power sequencing and fail-safe memory retention.

IC Role / Device Role / Timing Role: Monitors primary 5V supply (V_TRIP1) and unregulated 12V intermediate bus (V_2MON via resistor divider); triggers V2FAIL interrupt for predictive power-fail handling.

Use Value: Enables graceful shutdown of packet buffers; maintains MAC address tables in SRAM during brief AC outages; reduces MTTR via fault detection register logging.

Desktop Motherboard BIOS Protection

Medical Diagnostic Equipment

Use Scenario: ATX motherboards where CMOS real-time clock and BIOS configuration must survive AC power loss.

IC Role / Device Role / Timing Role: Provides power-on reset with 200ms t_PURST, monitors +5VSB standby rail, and backs up RTC SRAM via V_BATT input from coin cell.

Use Value: Guarantees reliable boot initialization after cold start; prevents BIOS corruption during sudden power loss; simplifies layout with single-chip solution.

Use Scenario: Portable ultrasound devices with lithium battery backup and strict IEC 60601-1 power integrity requirements.

IC Role / Device Role / Timing Role: Supervises main 3.3V system rail and battery voltage; uses watchdog to detect firmware hangs; stores calibration data in protected EEPROM.

Use Value: Ensures patient data persistence during battery swaps; meets Class BF isolation requirements via galvanically isolated reset signaling; supports audit-trail logging in nonvolatile memory.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MAX6820ETA+	Single-supply monitor (V_CC only); no V_2MON input; 256-byte EEPROM; 10-pin µMAX package.	Lacks secondary voltage monitoring and battery switchover; suitable only for basic reset + memory needs.	Select when dual-monitoring is unnecessary and board space is constrained; verify t_PURST and EEPROM size match requirements.
TPS3823MPW	Dual-supply monitor (4.63V/2.93V thresholds); no EEPROM; no battery switch; 8-pin SOIC; 3.5µA quiescent current.	Requires external EEPROM and discrete battery switch circuit; lower power but higher BOM count.	Choose when ultra-low standby current is critical and system design allows separation of supervision and memory functions.

Compared with MAX6820ETA+ and TPS3823MPW, the X40420S14I-B uniquely integrates dual-voltage supervision, battery-backed V_OUT, and 4kbit EEPROM in a single 14-pin package - reducing component count, PCB area, and qualification effort for systems requiring coordinated power fail response and nonvolatile storage.

Availability

X40420S14I-B is available at Aetrix Electronics and suitable for industrial process controllers, network routers, desktop motherboards, and medical diagnostic equipment requiring stable component supply, long-lifecycle support, and guaranteed traceability.

Supply support for X40420S14I-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 was a fabless semiconductor company specializing in nonvolatile memory and power management ICs, acquired by Renesas Electronics in 2008. Its legacy products emphasize reliability, low power, and integration for embedded systems.

The X40420/X40421 family was designed to consolidate power-on reset, watchdog, dual-supply monitoring, battery backup switching, and EEPROM into one die - targeting cost-sensitive, space-constrained applications in communications and industrial automation.

FAQ

What is the reset polarity of the X40420S14I-B?

The X40420S14I-B features an active-HIGH open-drain RESET output (pin 6), consistent with the X40420 variant designation. This differs from the X40421's active-LOW RESET. The output remains HIGH during normal operation and goes LOW only during power-up, brownout, or manual reset events - ensuring compatibility with microcontrollers expecting high-active reset signaling.

Can the V_TRIP2 threshold of the X40420S14I-B be reprogrammed?

Yes, the X40420S14I-B's V_TRIP2 threshold (factory-set to 2.6V ±2%) can be reprogrammed down to 0.9V using a defined I²C sequence involving WDO pin voltage control and specific slave address writes (A0h, byte address 09h). This procedure requires V_CC = 5V and does not affect EEPROM contents - enabling precise tailoring for custom power-fail warning levels.

How does the battery switchover function work in the X40420S14I-B?

The X40420S14I-B's battery switchover activates when V_CC drops below V_TRIP1 (4.6V) and V_BATT – 0.03V. V_OUT then connects to V_BATT through an 80Ω switch, supplying up to 250µA to preserve SRAM data. Hysteresis (±0.03V) prevents oscillation near the threshold. BATT-ON (pin 13) goes HIGH to indicate battery mode - allowing external circuit control.

What is the maximum I²C clock frequency supported by the X40420S14I-B?

The X40420S14I-B supports standard-mode I²C operation up to 400kHz, as specified in its datasheet. This allows efficient access to its 4kbit EEPROM and configuration registers without requiring slow bit-banged interfaces. The SDA and SCL pins include internal input buffers and open-drain outputs, requiring external pull-up resistors per I²C bus specifications.

Does the X40420S14I-B include hardware write protection for its EEPROM?

Yes, the X40420S14I-B implements Block Lock™ hardware write protection controlled by the BP bit in its nonvolatile control register. When BP = 1, writes to addresses 0x100–0x1FF (upper 256 bytes) are blocked; when BP = 0, the entire EEPROM array is unprotected. Additional protection is provided by the WP pin (pin 10), which globally disables all writes when driven HIGH.

X40420S14I-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:: 2

Voltage - Threshold:: 2.6V, 4.6V

Output:: Open Drain, Open Drain

Reset:: Active High/Active Low

Reset Timeout:: Adjustable/Selectable

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 14-SOIC

X40420S14I-B FAQ

1.How can I place an order for X40420S14I-B through Aetrix?

Please submit a Request for Quotation (RFQ) for X40420S14I-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 X40420S14I-B reliable?

The price and inventory of X40420S14I-B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for X40420S14I-B is usually 5 days.

3.What payment methods are accepted for X40420S14I-B?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for X40420S14I-B transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for X40420S14I-B?

X40420S14I-B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your X40420S14I-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 X40420S14I-B?

For technical support, including X40420S14I-B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your X40420S14I-B requirements.

6.How does Aetrix verify that X40420S14I-B is sourced from the original manufacturer or authorized distributors?

All X40420S14I-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 X40420S14I-B meets industry standards.

7.What is the process for return or replacement of X40420S14I-B?

All X40420S14I-B units undergo pre-shipment inspection (PSI). If there is an issue with X40420S14I-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 X40420S14I-B part is unused and in its original packaging.

Return procedure for X40420S14I-B:

1.Submit a request within 90 days.

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

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