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Analog Devices Inc./Maxim Integrated MAX6420UK31-T
- Part No.:
- MAX6420UK31-T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-74A, SOT-753
- Datasheet:
-
MAX6420UK31-T.pdf
- Description:
- IC SUPERVISOR 2 CHANNEL SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:15,000
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Product details
Overview
MAX6420UK31-T from Maxim Integrated is a low-power, dual-voltage microprocessor reset supervisor IC with one factory-trimmed VCC reset threshold (3.075V min / 3.152V max) and one adjustable RESET IN input (1.205V–1.255V threshold), open-drain active-low RESET output, capacitor-adjustable reset timeout, and operation from -40°C to +125°C in SOT23-5. It monitors critical power rails in automotive and industrial controllers to prevent code-execution errors during brownout.
For engineers reviewing the MAX6420UK31-T datasheet, MAX6420UK31-T pinout, MAX6420UK31-T application, or MAX6420UK31-T equivalent, this page delivers verified electrical parameters, dual-threshold monitoring behavior, SRT capacitor timing derivation, open-drain interface constraints, and automotive-grade thermal performance - all confirmed from Maxim's official Rev 6 datasheet (3/2014).
Technical Context
The MAX6420UK31-T integrates two independent voltage comparators: one laser-trimmed for VCC monitoring at 3.075V–3.152V (suffix "31"), and a second high-impedance comparator on RESET IN with fixed 1.205V–1.255V threshold for external resistor-divider–based voltage monitoring (e.g., 1.8V, 2.5V, or 3.3V rails). Reset assertion occurs if either voltage falls below its respective threshold.
Reset deassertion is controlled by an internal 240nA current source charging an external capacitor (CSRT) connected to SRT; the timeout period tRP = (2.71 × 10⁶) × CSRT + 275µs. The open-drain RESET output supports logic-level translation up to 5.5V and requires an external pullup for proper µP interface.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Reset Threshold | 3.075V (min) to 3.152V (max) - factory-trimmed for precise 3.1V nominal rail monitoring without external components |
| RESET IN Threshold | 1.205V–1.255V - fixed internal reference enabling accurate external voltage monitoring via resistor divider |
| Supply Current | 1.7µA (typ) at +25°C - enables multi-year battery life in portable and remote sensor applications |
| Reset Timeout Range | 275µs (min, CSRT = 0F) to >100ms (with nF-range CSRT) - fully configurable for diverse µP reset hold requirements |
| Operating Temperature | -40°C to +125°C - qualified for under-hood automotive and industrial control environments |
| RESET Output Type | Active-low open-drain - allows level-shifting to 0–5.5V logic supplies and wired-OR reset bus configurations |
| Quiescent Supply Range | 1.0V to 5.5V - guarantees valid reset assertion even during deep brownout down to 1V VCC |
Pinout & Package
SOT23-5 package (5-pin, 1.6mm × 2.9mm, 0.95mm height), RoHS-compliant, tape-and-reel delivery. Pin 1 marked with dot; top-side marking "ADZA" per Standard Versions Table.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - RESET | Open-drain active-low reset output | Must be pulled up externally; sinks ≥50µA at VCC ≥1.0V; compatible with 0–5.5V logic domains |
| 2 - GND | Ground reference | Primary return path for internal comparators, SRT current source, and RESET sink current |
| 3 - RESET IN | Adjustable voltage monitor input | High-impedance (≤10nA leakage); connects to center tap of R1/R2 divider to set VMON_TH = 1.26V × (R1+R2)/R2 |
| 4 - MR | Manual reset input | Not present on MAX6420 - pin 4 is no-connect (NC); manual reset implemented externally via switch across R2 |
| 5 - SRT | Reset timeout capacitor connection | 240nA precision current source charges CSRT to 0.65V; trace must be short, low-leakage, and noise-isolated |
| - VCC | Supply and fixed-threshold monitor input | Powers device and feeds factory-trimmed comparator; valid operation from 1.0V to 5.5V |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent voltage monitoring | Simultaneously supervises VCC (3.1V nominal) and a second rail (e.g., 1.8V, 2.5V) via external resistor divider on RESET IN |
| Capacitor-programmable reset timeout | Enables precise, application-specific reset hold times (275µs to 100+ ms) without trimming resistors or firmware changes |
| Open-drain RESET with wide voltage compatibility | Supports interfacing to µPs with 1.8V, 3.3V, or 5V I/O domains using a single external pullup resistor |
| Guaranteed operation down to VCC = 1.0V | Ensures reliable reset assertion during severe brownout conditions before system power collapse |
| Automotive temperature grade | Full -40°C to +125°C operation validated for engine control units, ADAS modules, and body electronics |
Applications
| Automotive Engine Control Unit (ECU) | Industrial PLC Power Monitoring |
|---|---|
Use Scenario: Monitors both 3.3V microcontroller supply and 1.8V sensor interface rail in an under-hood ECU exposed to thermal cycling and load dump transients. IC Role / Device Role / Timing Role: Dual-threshold supervisor asserting open-drain RESET until both rails stabilize post-brownout; timeout set to 50ms via 18nF SRT capacitor. Use Value: Prevents erratic MCU execution during cold-cranking voltage sag; eliminates need for two discrete supervisors or custom ASIC logic. |
Use Scenario: Ensures deterministic restart of a programmable logic controller after AC/DC converter output dip due to motor startup surge. IC Role / Device Role / Timing Role: Supervises 24V-derived 5V logic rail (via VCC pin) and isolated 3.3V FPGA configuration rail (via RESET IN divider), holding RESET until both recover. Use Value: Guarantees FPGA reconfiguration completes before CPU boot sequence begins - avoids configuration lockup or metastability. |
| Medical Infusion Pump Controller | Battery-Powered IoT Sensor Node |
Use Scenario: Validates stable 3.1V main processor rail and 1.25V analog front-end rail in a Class II medical device requiring fail-safe power sequencing. IC Role / Device Role / Timing Role: Generates hardware reset pulse only when both monitored voltages exceed thresholds and remain stable for ≥10ms (CSRT = 3.3nF). Use Value: Meets IEC 62304 safety requirement for deterministic power-on reset without software dependency or timing drift. |
Use Scenario: Provides ultra-low-power reset supervision for a LoRaWAN node powered by coin-cell battery, monitoring 3.0V LDO output and 1.8V RF transceiver rail. IC Role / Device Role / Timing Role: Draws only 1.7µA quiescent current while continuously checking both rails; asserts RESET on first undervoltage event. Use Value: Extends battery life beyond 5 years while ensuring reliable wake-from-sleep recovery and preventing corrupted sensor data transmission. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-voltage reset supervisor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6418UK31-T | Same dual-monitor architecture and SOT23-5 package, but features active-low push-pull RESET (not open-drain); no external pullup required. | Preferred where board space prohibits adding pullup resistor or where µP reset pin requires driven low/high (not open-collector). | Select MAX6418UK31-T if push-pull drive simplifies layout; otherwise MAX6420UK31-T offers superior logic-level flexibility. |
| TPS3808G33DBVR | Single-input (3.3V fixed), push-pull output, 1.6µA ICC, but lacks adjustable RESET IN and dual-rail capability. | Only suitable for single-rail systems; cannot replace MAX6420UK31-T in dual-voltage monitoring without redesign. | Use TPS3808G33DBVR only for cost-sensitive single-supply applications; not a functional substitute for dual-monitoring use cases. |
Compared with MAX6418UK31-T, MAX6420UK31-T trades push-pull simplicity for open-drain interoperability across mixed-voltage systems; compared with TPS3808G33DBVR, it adds essential dual-threshold supervision at slightly higher BOM count but enables robust multi-rail fault detection unattainable with single-input supervisors.
Availability
MAX6420UK31-T is available at Aetrix Electronics and suitable for automotive engine control units, industrial PLCs, medical infusion pumps, and battery-powered IoT sensor nodes requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX6420UK31-T 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
Maxim Integrated (now part of Analog Devices) designs precision analog and mixed-signal ICs for demanding industrial, automotive, and medical applications, emphasizing reliability, low power, and high integration.
The MAX6412–MAX6420 family was engineered specifically for robust, capacitor-configurable µP reset supervision in harsh environments - delivering dual-rail monitoring, sub-2µA quiescent current, and guaranteed operation from -40°C to +125°C.
FAQ
What is the exact VCC reset threshold voltage for MAX6420UK31-T?
The MAX6420UK31-T has a factory-trimmed VCC reset threshold of 3.075V (minimum), 3.152V (maximum), and 3.114V (typical), corresponding to suffix "31" per Table 1 in the datasheet. This 3.1V nominal threshold is laser-trimmed for accuracy across -40°C to +125°C, eliminating need for external calibration.
Does MAX6420UK31-T include a manual reset (MR) input?
No, MAX6420UK31-T does not feature a dedicated MR input. Pin 4 is no-connect (NC). Manual reset functionality must be implemented externally by placing a momentary switch in parallel with R2 in the RESET IN resistor divider network - closing the switch pulls RESET IN to ground and triggers reset, as described in Figure 2 of the datasheet.
How do I calculate the SRT capacitor value for a desired reset timeout on MAX6420UK31-T?
Use the formula CSRT = (tRP − 275µs) / 2.71×10⁶, where tRP is the desired timeout in seconds and CSRT is in farads. For example, a 50ms timeout requires CSRT = (0.05 − 0.000275) / 2.71×10⁶ ≈ 18.3nF. Use low-leakage ceramic capacitors; avoid electrolytics or high-DA types that degrade timing accuracy.
Can MAX6420UK31-T monitor a 2.5V rail using the RESET IN pin?
Yes. Connect a resistor divider (e.g., R1 = 976kΩ, R2 = 1MΩ) between the 2.5V rail and GND, with RESET IN tied to the divider midpoint. The MAX6420UK31-T's internal 1.205V–1.255V comparator threshold yields VMON_TH = 1.26V × (R1 + R2)/R2 ≈ 2.5V. Leakage-current–optimized resistors (≥1MΩ) maintain <2.5µA total divider current.
What is the maximum voltage the open-drain RESET output of MAX6420UK31-T can tolerate?
The open-drain RESET output of MAX6420UK31-T is rated for up to +6.0V (absolute maximum) and operates reliably with pullup voltages from 0V to 5.5V, as specified in the Absolute Maximum Ratings table. This enables direct interfacing to 1.8V, 3.3V, or 5V µP reset inputs without level translators - provided the external pullup resistor is sized appropriately (e.g., 10kΩ for 5V, 4.7kΩ for 3.3V).
MAX6420UK31-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Multi-Voltage Supervisor
- Number of Voltages Monitored:
- 2
- Voltage - Threshold:
- 3.075V, Adj
- Output:
- Open Drain or Open Collector
- Reset:
- Active Low
- Reset Timeout:
- Adjustable/Selectable
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
MAX6420UK31-T FAQ
1.How can I place an order for MAX6420UK31-T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6420UK31-T 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 MAX6420UK31-T reliable?
The price and inventory of MAX6420UK31-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6420UK31-T is usually 5 days.
3.What payment methods are accepted for MAX6420UK31-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6420UK31-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6420UK31-T?
MAX6420UK31-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6420UK31-T 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 MAX6420UK31-T?
For technical support, including MAX6420UK31-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6420UK31-T requirements.
6.How does Aetrix verify that MAX6420UK31-T is sourced from the original manufacturer or authorized distributors?
All MAX6420UK31-T 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 MAX6420UK31-T meets industry standards.
7.What is the process for return or replacement of MAX6420UK31-T?
All MAX6420UK31-T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6420UK31-T, 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 MAX6420UK31-T part is unused and in its original packaging.
Return procedure for MAX6420UK31-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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