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Renesas X40021S14I-B
- Part No.:
- X40021S14I-B
- Manufacturer:
- Renesas
- Category:
- Supervisors
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
X40021S14I-B.pdf
- Description:
- IC SUPERVISOR 2 CHANNEL 14SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:579
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Product details
Overview
X40021S14I-B from Intersil is a dual-voltage supervisor IC with integrated CPU supervisor, watchdog timer, battery backup switch, and 2-wire interface. It monitors VCC (4.6V ±1%) and V2MON (2.6V ±2%), asserts active-low RESET on brownout or manual reset, provides 50mA VOUT switching from VCC/VBATT, and supports 400kHz I²C communication. Used in industrial servers for power-fail detection and SRAM backup.
For engineers reviewing the X40021S14I-B datasheet, X40021S14I-B pinout, X40021S14I-B application, or X40021S14I-B equivalent, key selection considerations include its -40°C to +85°C industrial temperature range, programmable VTRIP2 down to 0.9V, selectable 50ms–800ms power-on reset timeout, 25µA watchdog-active standby current, and 14-lead SOIC package with Pb-free RoHS compliance.
Technical Context
The X40021S14I-B integrates four core functions: (1) dual voltage monitoring with factory-set VTRIP1 = 4.6V and VTRIP2 = 2.6V, both reprogrammable via 2-wire interface; (2) power-on reset generation with user-selectable tPURST (50/200/400/800ms); (3) watchdog timer with configurable intervals (25ms/200ms/1.4s/off) triggered by SDA/SCL activity; and (4) system battery switch routing VOUT to VCC or VBATT based on hysteresis thresholds (±30mV).
Its fault detection register (FDR) captures root cause of reset events-manual reset, watchdog timeout, or low-VCC/V2MON failure-as volatile status bits readable at address 0xFF. The device operates from 2.7V–5.5V, maintains RESET validity down to VCC = 1V, and delivers 1µA battery backup current while holding SRAM data during main supply loss.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VTRIP1 Threshold | 4.6V ±1% - Factory-programmed primary supply monitor level; resets system if VCC drops below this point. |
| VTRIP2 Threshold | 2.6V ±2% - Factory-programmed secondary supply monitor level; asserts V2FAIL when V2MON falls below this value. |
| Power-on Reset Timeout (tPURST) | Selectable 50ms / 200ms / 400ms / 800ms - Configurable delay before releasing RESET after VCC exceeds VTRIP1. |
| Watchdog Timeout | 25ms / 200ms / 1.4s / off - Nonvolatile control bits WD1/WD0 set interval; WDO goes active if SDA/SCL sequence not received within window. |
| Standby Current (WD on) | 25µA typical - Total quiescent draw during normal operation with watchdog enabled; enables low-power embedded monitoring. |
| VOUT Switching Capability | 50mA from VCC, 250µA from VBATT - Internal MOSFET switch sustains SRAM voltage during VCC failure without external components. |
| Operating Temperature | -40°C to +85°C - Industrial-grade thermal rating confirmed in ordering code "I" suffix; suitable for harsh-environment deployments. |
| Package | 14-lead SOIC (150 mil), MDP0027 - Standard surface-mount footprint with RoHS-compliant Pb-free plus anneal finish. |
Pinout & Package
14-lead SOIC (150 mil) package per MDP0027 drawing; RoHS-compliant Pb-free plus anneal termination.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 V2FAIL | Open-drain fail output | Asserts LOW when V2MON < VTRIP2; no power-up delay; used for early power-fail interrupt or OR-ed reset signaling. |
| 2 V2MON | Secondary voltage input | Monitors unregulated or auxiliary supply; threshold programmable down to 0.9V; powered by VOUT. |
| 3 LOWLINE | Early low-VCC detect | Open-drain output pulled HIGH externally; goes LOW when VCC < VTRIP1, enabling preemptive system shutdown. |
| 4 WDO | Watchdog timeout output | Active-low open drain; asserts when watchdog timer expires; can be tied to MCU reset or fault logging circuitry. |
| 5 MR | Debounced manual reset | Pull-to-ground input with internal pull-up; initiates full reset sequence including tPURST delay; eliminates external RC debounce. |
| 6 RESET | Active-low reset output | X40021 variant: open-drain RESET asserted when VCC < VTRIP1 or MR active; holds for programmed tPURST. |
| 7 VSS | Ground reference | Primary return path for all analog and digital circuits; must be low-impedance connection to minimize noise coupling. |
| 8 SDA | 2-wire serial data | Bidirectional open-drain I²C bus line; used for programming VTRIPx, reading FDR, configuring watchdog and tPURST. |
| 9 SCL | 2-wire serial clock | Master-generated clock synchronizing all I²C transactions; required for VTRIP reprogramming and register access. |
| 10 WP | Write protect input | Hardware lock: HIGH disables all writes to registers and memory; internal pull-down ensures default write-enable state. |
| 11 VBATT | Battery backup supply | Input for coin-cell or backup battery; powers internal logic and VOUT switch when VCC fails; connect to GND if unused. |
| 12 VOUT | System backup output | Switches between VCC and VBATT with 30mV hysteresis; requires 0.1µF capacitor for stability; drives SRAM VDD directly. |
| 13 BATT-ON | Battery active indicator | CMOS output HIGH only when VOUT = VBATT; drives external PNP transistor for >50mA load support during main supply operation. |
| 14 VCC | Main supply input | 2.7V–5.5V operating range; powers all internal blocks; VTRIP1 monitoring starts at 1V; RESET remains valid down to 1V. |
Key Features
| Feature | Design Value |
|---|---|
| Dual voltage supervision with reprogrammable thresholds | VTRIP1 and VTRIP2 adjustable via 2-wire interface using high-voltage programming sequence; supports custom trip points down to 0.9V. |
| Integrated battery backup switch with hysteresis | VOUT automatically selects higher of VCC or VBATT with ±30mV hysteresis; prevents oscillation during switchover; sustains SRAM with 1µA battery current. |
| Fault Detection Register (FDR) | Volatile 8-bit register at address 0xFF captures reset cause (LV1F/LV2F/WDF/MRF); enables deterministic post-reset diagnostics without external logic. |
| Selectable power-on reset and watchdog timing | Nonvolatile PUP1/PUP0 and WD1/WD0 bits configure tPURST (50–800ms) and watchdog interval (25ms–1.4s) independently of firmware. |
| Low-power CMOS design | 25µA standby with watchdog enabled, 6µA with watchdog disabled, and 1µA battery mode current - extends backup runtime in critical systems. |
| Industrial temperature grade and RoHS compliance | -40°C to +85°C operation verified per ordering code "I"; Pb-free plus anneal finish meets IPC/JEDEC J-STD-020 reflow standards. |
Applications
| Industrial Process Controllers | Network Server Power Management |
|---|---|
|
Use Scenario: Continuous operation in factory automation PLCs where main AC-DC supply may experience brownouts or transients. IC Role / Device Role / Timing Role: Dual-supply monitor detects VCC sag and auxiliary 3.3V rail collapse; asserts RESET and V2FAIL to halt CPU and trigger safe shutdown sequence. Use Value: Prevents corrupted I/O state or firmware execution during undervoltage; hysteresis avoids chatter; battery-backed VOUT preserves configuration EEPROM during extended outages. |
Use Scenario: High-availability rack-mounted servers requiring graceful shutdown and persistent memory retention during grid failure. IC Role / Device Role / Timing Role: Supervises 5V main rail and 3.3V standby rail; uses V2FAIL to signal impending power loss to BMC; triggers watchdog if host OS hangs during shutdown. Use Value: Enables 250µA battery-powered SRAM holdover for 72+ hours; FDR identifies whether reset was caused by power loss, software hang, or operator action. |
| Communications Routers | Intelligent Instrumentation |
|
Use Scenario: Carrier-grade edge routers deployed in uncontrolled environments with unstable DC inputs from PoE or telecom rectifiers. IC Role / Device Role / Timing Role: Monitors primary 5V PoE-derived supply and secondary 2.6V PHY voltage; uses programmable VTRIP2 to match exact PHY brownout spec. Use Value: Eliminates need for discrete voltage detectors and reset generators; 400kHz I²C allows real-time threshold tuning during field calibration without hardware change. |
Use Scenario: Portable handheld test equipment with lithium coin-cell backup and precision analog front-end requiring stable reference during battery swaps. IC Role / Device Role / Timing Role: Provides seamless VOUT switchover from main supply to backup cell; LOWLINE alerts microcontroller 100ms before VCC dropout to save volatile calibration data. Use Value: 1µA battery current extends coin-cell life beyond 5 years; tPURST=50ms ensures fast boot after battery replacement without firmware delay penalties. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-voltage supervisor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6361KA29D3+ | Fixed 2.93V/4.63V thresholds; no VTRIP reprogramming; 12-lead µMAX package; 1.5µA battery current. | Lacks 2-wire interface and programmability; suited for cost-sensitive designs where thresholds match standard rails exactly. | Choose MAX6361KA29D3+ only if fixed thresholds suffice and SOIC footprint is not required. |
| TPS3808G33DBVR | Single-supply monitor (3.3V); no secondary voltage input or battery switch; SOT-23-6 package; 1.1µA quiescent current. | Cannot replace dual-monitoring or SRAM backup functions; requires external circuitry for V2MON and battery switchover. | Use TPS3808G33DBVR only for simple 3.3V-only supervision where X40021S14I-B's dual-rail and backup features are unnecessary. |
Compared with MAX6361KA29D3+ and TPS3808G33DBVR, the X40021S14I-B uniquely combines reprogrammable dual-threshold monitoring, integrated battery switchover, and I²C configurability in a single 14-pin SOIC - eliminating discrete components and enabling field-adaptable power management in industrial and telecom systems.
Availability
X40021S14I-B is available at Aetrix Electronics and suitable for industrial process controllers, network server power management, communications routers, and intelligent instrumentation requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for X40021S14I-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
Intersil (now part of Renesas Electronics) is a U.S.-based semiconductor company specializing in precision analog, power management, and interface ICs for industrial, computing, and communications markets.
The X40021 series belongs to Intersil's CPU supervisor product line, designed specifically to consolidate power monitoring, reset control, watchdog protection, and battery backup into one IC for space-constrained, reliability-critical embedded systems.
FAQ
What is the factory-default VTRIP1 and VTRIP2 for X40021S14I-B?
The X40021S14I-B ships with factory-programmed VTRIP1 = 4.6V ±1% and VTRIP2 = 2.6V ±2%, corresponding to the "-B" suffix in the ordering matrix. These values are stored nonvolatilely and remain stable over temperature and time unless reprogrammed via the 2-wire interface using the high-voltage programming sequence defined in the datasheet.
Does X40021S14I-B support true pin-compatible replacement for X40020S14I-B?
No - X40021S14I-B and X40020S14I-B differ in RESET polarity: X40021S14I-B provides active-low open-drain RESET, while X40020S14I-B provides active-high RESET. Though pinout and package are identical, direct substitution requires PCB-level logic inversion or firmware adaptation to handle the opposite reset assertion state.
How does the battery switchover hysteresis work on X40021S14I-B?
The X40021S14I-B implements ±30mV hysteresis around the VBATT switchover point: VOUT connects to VBATT when VCC falls below VBATT − 0.03V, and reconnects to VCC only when VCC rises above VBATT + 0.03V. This prevents oscillation during marginal supply conditions and is implemented entirely in analog circuitry without software involvement.
Can X40021S14I-B operate with VCC below 2.7V?
No - the X40021S14I-B specifies a minimum VCC of 2.7V for guaranteed operation. While RESET remains valid down to VCC = 1V for brownout detection, internal logic, I²C interface, and VTRIP programming require ≥2.7V. Operation below 2.7V may result in undefined behavior, failed writes, or incomplete reset assertion.
What is the purpose of the BATT-ON pin on X40021S14I-B?
The BATT-ON pin on X40021S14I-B is a CMOS output that goes HIGH only when VOUT is sourced from VBATT (i.e., during main supply failure). It is designed to drive an external PNP pass transistor, enabling >50mA load current during normal VCC operation while automatically disabling the transistor during battery backup mode - preserving battery capacity for critical SRAM retention only.
X40021S14I-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 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
X40021S14I-B FAQ
1.How can I place an order for X40021S14I-B through Aetrix?
Please submit a Request for Quotation (RFQ) for X40021S14I-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 X40021S14I-B reliable?
The price and inventory of X40021S14I-B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for X40021S14I-B is usually 5 days.
3.What payment methods are accepted for X40021S14I-B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for X40021S14I-B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for X40021S14I-B?
X40021S14I-B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your X40021S14I-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 X40021S14I-B?
For technical support, including X40021S14I-B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your X40021S14I-B requirements.
6.How does Aetrix verify that X40021S14I-B is sourced from the original manufacturer or authorized distributors?
All X40021S14I-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 X40021S14I-B meets industry standards.
7.What is the process for return or replacement of X40021S14I-B?
All X40021S14I-B units undergo pre-shipment inspection (PSI). If there is an issue with X40021S14I-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 X40021S14I-B part is unused and in its original packaging.
Return procedure for X40021S14I-B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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