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

Renesas X40420S14-B

Name: X40420S14-B
Brand: Renesas
SKU: X40420S14-B
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: X40420S14-B

Manufacturer:: Renesas

Category:: Supervisors

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

Datasheet:: X40420S14-B.pdf

Description:: IC SUPERVISOR 2 CHANNEL 14SOIC

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Product details

Overview

X40420S14-B from Xicor is a dual-voltage supervisor IC with integrated CPU reset controller, watchdog timer, battery backup switch, and 4kbit EEPROM. It monitors V_CC (4.6V ±1%) and V_2MON (2.6V ±2%), asserts active-HIGH RESET during brownout or manual reset, delivers up to 50mA from V_CC to V_OUT, and supports 400kHz I²C interface for EEPROM access - used in industrial process controllers requiring fail-safe power management and nonvolatile configuration storage.

For engineers reviewing the X40420S14-B datasheet, X40420S14-B pinout, X40420S14-B application, or X40420S14-B equivalent, key selection considerations include its dual-threshold voltage detection (4.6V/2.6V), active-HIGH RESET output (X40420 variant), battery switchover logic with BATT-ON control, 200ms default power-on reset timeout, and Block Lock™-protected EEPROM with 100,000 write cycles.

Technical Context

The X40420S14-B implements two independent voltage comparators: one for V_CC (V_TRIP1 = 4.6V ±1%) triggering RESET, and another for V_2MON (V_TRIP2 = 2.6V ±2%) driving V_2FAIL. Its reset generation logic holds RESET active for a user-selectable t_PURST (50/200/400/800ms) after power-up or manual reset release.

Watchdog functionality is controlled by nonvolatile WD1/WD0 bits (25ms/200ms/1.4s/off), restarted via I²C START–SCL toggle–STOP sequence on SDA/SCL. The battery switch routes V_OUT to V_CC or V_BATT based on hysteresis thresholds (±30mV around V_BATT), while BATT-ON provides CMOS-level enable for external PNP pass transistors.

Key Specifications

Parameter	Value and Actual Design Meaning
V_TRIP1	4.6V ±1% - triggers active-HIGH RESET when V_CC falls below threshold; ensures reliable microcontroller reset before brownout.
V_TRIP2	2.6V ±2% - sets V_2FAIL assertion point for secondary supply monitoring or power-fail warning.
t_PURST	200ms default - programmable delay (50/200/400/800ms) that holds RESET active post-power-up to stabilize oscillator and FPGA config.
Watchdog timeout	200ms factory default - selectable interval prevents runaway firmware execution without requiring external components.
I²C interface	400kHz max - enables fast EEPROM read/write and register access using standard 2-wire bus with SDA/SCL pins.
EEPROM endurance	100,000 write cycles - supports frequent calibration or configuration updates in field-deployed equipment.
V_OUT drive capability	50mA from V_CC, 250µA from V_BATT - powers SRAM or low-current peripherals during main supply failure.

Pinout & Package

Package: 14-lead SOIC (S14-B suffix denotes SOIC package per ordering information).

Pin/Terminal	Circuit Role	Design Meaning
1 V2FAIL	Open-drain power-fail indicator	Active-LOW signal asserts when V_2MON < V_TRIP2; used for interrupt-driven power-fail notification or OR-ed with RESET.
2 V2MON	Secondary voltage monitor input	Accepts unregulated or auxiliary supply; internal comparator compares against V_TRIP2 = 2.6V ±2%.
3 LOWLINE	Early V_CC undervoltage flag	Open-drain output pulled HIGH externally; goes LOW when V_CC < V_TRIP1, enabling preemptive system shutdown.
4 WDO	Watchdog timeout output	Active-LOW open-drain signal asserts if microcontroller fails to restart watchdog within selected interval.
5 MR	Debounced manual reset input	Pulled HIGH internally; asserting LOW initiates RESET with built-in debounce, eliminating external RC network.
6 RESET	Active-HIGH reset output (X40420)	Drives microcontroller reset pin directly; stays HIGH until V_CC exceeds V_TRIP1 and t_PURST expires.
7 V_SS	Ground reference	Common return path for all analog and digital circuitry; must be low-impedance connection to system ground plane.
8 SDA	I²C bidirectional data line	Open-drain pin with always-active input buffer; requires external pull-up; used for EEPROM reads/writes and register access.
9 SCL	I²C clock input	Controls timing of serial transfers; toggling SCL with START/STOP on SDA resets watchdog timer.
10 WP	Hardware write protect	Logic HIGH disables all writes to EEPROM and registers; internal pull-down ensures safe default state.
11 V_BATT	Backup battery supply input	Provides standby power to V_OUT and internal logic when V_CC fails; connect to coin cell or supercapacitor.
12 V_OUT	System backup output	Switches between V_CC and V_BATT with 30mV hysteresis; supplies SRAM or real-time clocks during power loss.
13 BATT-ON	Battery switchover status	CMOS HIGH when V_OUT = V_BATT; drives external PNP transistor to boost current delivery during normal operation.
14 V_CC	Main supply input	Operates from 2.7V to 5.5V; powers all internal circuits except EEPROM write operations, which draw from V_CC.

Key Features

Feature	Design Value
Dual programmable voltage thresholds	V_TRIP1 and V_TRIP2 can be reprogrammed via I²C using high-voltage pulse on WDO - enables fine-tuning for precision brownout detection without external resistors.
Integrated battery switchover with BATT-ON control	V_OUT automatically selects higher of V_CC or V_BATT with hysteresis; BATT-ON enables external PNP for >50mA loads - eliminates need for discrete diode-OR or load switches.
Nonvolatile fault detection register (FDR)	Tracks root cause of last reset (LV1F/LV2F/WDF/MRF) as volatile flags cleared only by software - accelerates field failure analysis without external logging.
Block Lock™ EEPROM protection	BP bit locks upper 256 bytes (100h–1FFh) against accidental writes - preserves critical calibration data or boot code in harsh environments.
Low-power standby modes	6µA typical with watchdog disabled, 25µA with watchdog enabled - extends battery life in always-on industrial sensors and remote telemetry units.

Applications

Industrial Process Controllers	Network Routers & Switches
Use Scenario: PLCs and DCS modules operating in temperature-variable factory floors where main supply sags during motor startups. IC Role / Device Role / Timing Role: Dual-voltage supervisor asserts RESET when V_CC drops below 4.6V and generates V_2FAIL if auxiliary 3.3V rail collapses - preventing corrupted I/O state transitions. Use Value: Prevents spurious relay actuation and sensor misreads during brownouts; EEPROM stores last valid setpoints for fast recovery after power restoration.	Use Scenario: Carrier-grade Ethernet switches with redundant power supplies and SRAM-based forwarding tables. IC Role / Device Role / Timing Role: Monitors primary 5V and secondary 3.3V rails; switches V_OUT to coin-cell backup when both fail, keeping SRAM alive for <10 seconds. Use Value: Enables graceful packet drain and configuration save before full shutdown; BATT-ON drives external transistor to sustain 100mA SRAM load during V_CC recovery.
Medical Diagnostic Equipment	Automated Test Equipment (ATE)
Use Scenario: Portable ultrasound machines with Li-ion battery backup and real-time image processing FPGAs. IC Role / Device Role / Timing Role: Uses V_2MON to track battery voltage; asserts V_2FAIL at 2.6V to trigger low-battery warning before shutdown, while RESET holds FPGA in reset until stable 1.2V core rail. Use Value: Avoids partial image corruption during power transition; EEPROM retains last calibration coefficients for immediate post-boot accuracy verification.	Use Scenario: Rack-mounted ATE systems performing high-speed parametric testing with volatile test pattern memory. IC Role / Device Role / Timing Role: Supervises 5V analog supply and 3.3V digital supply; uses watchdog to detect hung test sequencer and force hard reset without operator intervention. Use Value: Reduces unscheduled downtime by auto-recovering from firmware hangs; fault register identifies whether failure was due to power sag (LV1F) or software lockup (WDF).

Industrial Process Controllers

Network Routers & Switches

Use Scenario: PLCs and DCS modules operating in temperature-variable factory floors where main supply sags during motor startups.

IC Role / Device Role / Timing Role: Dual-voltage supervisor asserts RESET when V_CC drops below 4.6V and generates V_2FAIL if auxiliary 3.3V rail collapses - preventing corrupted I/O state transitions.

Use Value: Prevents spurious relay actuation and sensor misreads during brownouts; EEPROM stores last valid setpoints for fast recovery after power restoration.

Use Scenario: Carrier-grade Ethernet switches with redundant power supplies and SRAM-based forwarding tables.

IC Role / Device Role / Timing Role: Monitors primary 5V and secondary 3.3V rails; switches V_OUT to coin-cell backup when both fail, keeping SRAM alive for <10 seconds.

Use Value: Enables graceful packet drain and configuration save before full shutdown; BATT-ON drives external transistor to sustain 100mA SRAM load during V_CC recovery.

Medical Diagnostic Equipment

Automated Test Equipment (ATE)

Use Scenario: Portable ultrasound machines with Li-ion battery backup and real-time image processing FPGAs.

IC Role / Device Role / Timing Role: Uses V_2MON to track battery voltage; asserts V_2FAIL at 2.6V to trigger low-battery warning before shutdown, while RESET holds FPGA in reset until stable 1.2V core rail.

Use Value: Avoids partial image corruption during power transition; EEPROM retains last calibration coefficients for immediate post-boot accuracy verification.

Use Scenario: Rack-mounted ATE systems performing high-speed parametric testing with volatile test pattern memory.

IC Role / Device Role / Timing Role: Supervises 5V analog supply and 3.3V digital supply; uses watchdog to detect hung test sequencer and force hard reset without operator intervention.

Use Value: Reduces unscheduled downtime by auto-recovering from firmware hangs; fault register identifies whether failure was due to power sag (LV1F) or software lockup (WDF).

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MAX6820EUK+T	Single 3.08V reset threshold; no V_2MON input; 1kbit EEPROM; 100kHz I²C only	Lacks secondary voltage monitoring and programmable V_TRIP2; suitable only for single-rail systems with lower EEPROM density needs	Select only if dual-supply monitoring is unnecessary and 4kbit EEPROM capacity is not required.
TPS3823MPW	Triple voltage monitor (3 thresholds); no EEPROM; no battery switch; push-pull RESET output	Provides three independent reset points but requires external EEPROM and discrete battery switchover circuitry	Choose when higher reset threshold granularity is needed and system design allows added board space for discrete support components.

Compared with MAX6820EUK+T and TPS3823MPW, the X40420S14-B uniquely integrates dual-threshold supervision, battery-backed V_OUT, and 4kbit Block Lock™ EEPROM in a single 14-pin SOIC - reducing BOM count by up to 7 components while enabling autonomous power-fail response without firmware intervention.

Availability

X40420S14-B is available at Aetrix Electronics and suitable for industrial process controllers, network infrastructure equipment, and medical diagnostic devices requiring stable component supply across extended product lifecycles.

Supply support for X40420S14-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, later acquired by Intersil (now part of Renesas Electronics).

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 embedded systems needing high reliability under variable input conditions.

FAQ

What is the function of the BATT-ON pin on the X40420S14-B?

The BATT-ON pin on the X40420S14-B is a CMOS-level output that goes HIGH when V_OUT is sourced from V_BATT, indicating battery backup mode. It is designed to drive the base of an external PNP transistor, enabling higher current delivery (>50mA) to SRAM or other peripherals during normal V_CC-powered operation. When V_CC fails and V_OUT switches to V_BATT, BATT-ON goes LOW, turning off the external transistor and isolating the battery from excessive load - preserving backup runtime for critical data retention in the X40420S14-B system.

How does the X40420S14-B differ from the X40421 variant?

The X40420S14-B differs from the X40421 primarily in its RESET output polarity: X40420S14-B provides an active-HIGH open-drain RESET signal, while X40421 provides active-LOW. Both share identical dual-voltage monitoring thresholds (4.6V/2.6V for X40420S14-B), EEPROM size, watchdog intervals, and pinout. The RESET polarity difference means X40420S14-B directly interfaces with microcontrollers requiring active-HIGH reset assertion, whereas X40421 suits those needing active-LOW - making them functionally identical except for this single logic-level distinction in the X40420S14-B implementation.

Can the voltage thresholds of the X40420S14-B be reprogrammed, and how?

Yes, both V_TRIP1 and V_TRIP2 thresholds of the X40420S14-B can be reprogrammed using a special I²C sequence involving a high-voltage pulse on the WDO pin. To increase a threshold, apply the desired voltage to V_1MON or V_2MON, then issue a START, apply programming voltage to WDO, send slave address A0h, byte address 01h (V_TRIP1) or 09h (V_TRIP2), data 00h, and STOP - followed by pulling WDO LOW. To decrease a threshold, first execute a reset sequence (byte address 03h or 0Bh), then program the new value. This procedure is documented in the X40420S14-B datasheet and does not affect EEPROM contents.

What is the purpose of the Fault Detection Register (FDR) in the X40420S14-B?

The Fault Detection Register (FDR) in the X40420S14-B is a volatile 8-bit register (address 0FFh) that records the root cause of the most recent system reset. Bits LV1F, LV2F, WDF, and MRF clear from '1' to '0' when V_CC undervoltage, V_2MON undervoltage, watchdog timeout, or manual reset occurs respectively. Software reads the FDR after reset to determine failure origin - for example, distinguishing between a power sag (LV1F=0) and firmware hang (WDF=0). The X40420S14-B requires the host to reinitialize the FDR to all '1's after each read to enable continued fault tracking.

Does the X40420S14-B support write protection for its EEPROM, and how is it implemented?

Yes, the X40420S14-B supports hardware and software write protection for its 4kbit EEPROM. Hardware protection is enabled by holding the WP pin HIGH, which disables all writes to memory and registers. Software protection uses the nonvolatile Block Protect (BP) bit: when BP=1, the upper 256-byte block (addresses 100h–1FFh) is locked against writes, preserving critical calibration data or boot code. Protection is enforced at the silicon level - attempted writes to locked regions are ignored and generate no acknowledge, ensuring robust data integrity in mission-critical X40420S14-B deployments.

X40420S14-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:: 0°C ~ 70°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 14-SOIC

X40420S14-B FAQ

1.How can I place an order for X40420S14-B through Aetrix?

Please submit a Request for Quotation (RFQ) for X40420S14-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 X40420S14-B reliable?

The price and inventory of X40420S14-B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for X40420S14-B is usually 5 days.

3.What payment methods are accepted for X40420S14-B?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for X40420S14-B transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for X40420S14-B?

X40420S14-B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your X40420S14-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 X40420S14-B?

For technical support, including X40420S14-B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your X40420S14-B requirements.

6.How does Aetrix verify that X40420S14-B is sourced from the original manufacturer or authorized distributors?

All X40420S14-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 X40420S14-B meets industry standards.

7.What is the process for return or replacement of X40420S14-B?

All X40420S14-B units undergo pre-shipment inspection (PSI). If there is an issue with X40420S14-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 X40420S14-B part is unused and in its original packaging.

Return procedure for X40420S14-B:

1.Submit a request within 90 days.

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

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