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Analog Devices Inc./Maxim Integrated MAX6420UK33+
- Part No.:
- MAX6420UK33+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-74A, SOT-753
- Datasheet:
-
MAX6420UK33+.pdf
- Description:
- IC SUPERVISOR 2 CHANNEL SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,438
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Product details
Overview
The MAX6420UK33+ from Maxim Integrated is a low-power microprocessor supervisor IC designed for dual-voltage monitoring in automotive and industrial embedded systems. It features a factory-trimmed 3.3V fixed VCC reset threshold (±2.5% over temperature), an adjustable RESET IN input (1.26V reference, monitors voltages ≥1.26V), and an active-low open-drain RESET output. Its capacitor-adjustable reset timeout (275µs to >5ms) and guaranteed reset validity down to VCC = 1V support reliable brownout recovery in battery-powered controllers.
For engineers reviewing the MAX6420UK33+ datasheet, MAX6420UK33+ pinout, MAX6420UK33+ application, or MAX6420UK33+ equivalent, key selection criteria include dual-supply monitoring capability, open-drain logic compatibility with mixed-voltage µPs, AEC-Q100 qualification (indicated by /V suffix variants), and SOT23-5 footprint constraints for space-constrained designs.
Technical Context
The MAX6420UK33+ implements two independent voltage-detection comparators: one laser-trimmed for VCC at 3.3V nominal (±2.5% over −40°C to +125°C), and one adjustable via external resistor divider referenced to a stable 1.26V internal threshold. Reset assertion occurs if either voltage falls below its respective threshold or manual reset is triggered.
Its reset timeout is generated by a precision 240nA current source charging an external capacitor (CSRT) to a 0.65V ramp threshold; deassertion requires full ramp completion. The open-drain RESET output supports pull-up to any supply ≤5.5V, enabling interoperability across logic families without level-shifting.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Reset Threshold | 3.30V ±2.5% (−40°C to +125°C); ensures accurate power-rail supervision for 3.3V systems under extreme temperature conditions. |
| RESET IN Reference | 1.26V ±33mV hysteresis; enables precise external voltage monitoring (e.g., 1.8V, 2.5V rails) using high-impedance resistor dividers. |
| Reset Timeout Range | 275µs (CSRT = 0) to 5.75ms (CSRT = 1500pF); externally programmable delay prevents premature µP release during slow-rising supplies. |
| Supply Current | 1.7µA typical at VCC ≤ 2.0V; ultra-low quiescent draw extends battery life in portable and always-on monitoring applications. |
| Operating Temp | −40°C to +125°C; fully specified for under-hood automotive and industrial control environments. |
| RESET Output Type | Active-low open-drain; allows wired-OR configuration and interface to µPs with different I/O voltage domains (e.g., 1.8V core, 3.3V I/O). |
| ESD Rating | ±2kV HBM; robustness against handling and board-level transients in manufacturing and field deployment. |
Pinout & Package
SOT23-5 package (5-pin, 2.9mm × 1.6mm × 1.1mm body, 0.95mm pitch), RoHS-compliant, lead-free (+ suffix), thermal resistance θJA = 255.9°C/W (multi-layer board).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - RESET | Open-drain reset output | Asserts low during fault; requires external pull-up; compatible with 0–5.5V logic domains. |
| 2 - GND | Ground reference | Common return path for all internal circuitry and external capacitor (CSRT). |
| 3 - RESET IN | Adjustable voltage monitor input | High-impedance node (10nA leakage); connects to center tap of resistor divider for secondary rail monitoring. |
| 4 - SRT | Reset timeout capacitor connection | 240nA precision current source; CSRT value directly sets timeout period per tRP = (2.71×10⁶)×CSRT + 275µs. |
| 5 - VCC | Power supply and primary monitor input | Supplies device and feeds fixed-threshold comparator; valid operation from 1.0V to 5.5V. |
Key Features
| Feature | Design Value |
|---|---|
| Dual-voltage monitoring | Simultaneously supervises VCC (3.3V fixed) and a second rail (e.g., 1.8V, 2.5V) via adjustable RESET IN, eliminating need for two discrete supervisors. |
| Capacitor-programmable timeout | Enables precise, application-specific reset hold time (275µs–5.75ms) without trimming resistors or firmware changes. |
| AEC-Q100 qualified variants | Available as /V versions (e.g., MAX6420UK33/V+) for automotive applications requiring validated reliability and extended temperature operation. |
| Low-voltage reset validity | Guaranteed RESET assertion down to VCC = 1V, ensuring deterministic behavior during deep brownout conditions before system collapse. |
| Transient immunity | Rejects VCC glitches ≤50µs duration when 100mV below threshold, preventing spurious resets in noisy power environments. |
Applications
| Automotive Engine Control Unit (ECU) | Industrial PLC I/O Module |
|---|---|
Use Scenario: Monitors both 3.3V microcontroller supply and 1.8V sensor interface rail in engine management systems exposed to wide temperature swings and electrical noise. IC Role / Device Role / Timing Role: Dual-rail supervisor asserting open-drain RESET to MCU and FPGA upon undervoltage on either rail; timeout set to 4.375ms for safe boot sequence. Use Value: Prevents erratic ECU behavior during cranking (low-battery dips) and ensures synchronized restart of digital and analog subsystems. | Use Scenario: Supervises 3.3V logic supply and 2.5V ADC reference rail in modular PLC backplane where multiple voltage domains coexist. IC Role / Device Role / Timing Role: Provides single-chip dual-threshold detection with open-drain output pulled to 3.3V, enabling shared reset bus across distributed I/O cards. Use Value: Reduces BOM count vs. dual discrete supervisors and simplifies layout by consolidating reset timing into one SOT23-5 footprint. |
| Battery-Powered Medical Monitor | Set-Top Box Power Management |
Use Scenario: Ensures reliable startup and brownout recovery in portable ECG devices powered by Li-ion batteries discharging from 4.2V to 3.0V. IC Role / Device Role / Timing Role: Uses 3.3V VCC threshold to detect main rail collapse and adjustable RESET IN to monitor backup 1.8V real-time clock supply. Use Value: Ultra-low 1.7µA supply current maximizes battery runtime while guaranteeing data integrity during power transitions. | Use Scenario: Manages power sequencing in consumer STBs with separate 3.3V SoC core and 1.2V DDR memory rails. IC Role / Device Role / Timing Role: Generates coordinated reset pulse after both rails stabilize, with timeout tuned to DDR initialization requirements. Use Value: Eliminates need for external RC timing networks and avoids firmware-based reset coordination delays. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6418UK33+ | Same dual-monitor architecture and SOT23-5 package, but features active-low push-pull RESET instead of open-drain. | Requires dedicated reset net; cannot share pull-up with other open-drain devices on same bus. | Select when driving a single µP with no bus-sharing requirement and lower output impedance is preferred. |
| TPS3808G33DBVR | Fixed 3.3V threshold only (no adjustable input); push-pull active-low RESET; higher ICC (8µA typ). | Single-rail supervision only; lacks dual-voltage capability and open-drain flexibility. | Select when cost sensitivity outweighs dual-rail need and higher quiescent current is acceptable. |
Compared with MAX6418UK33+, the MAX6420UK33+ trades push-pull drive strength for open-drain versatility in multi-device reset buses; compared with TPS3808G33DBVR, it adds critical dual-rail monitoring and cuts supply current by >75%, justifying its use in battery-critical or multi-rail systems.
Availability
MAX6420UK33+ is available at Aetrix Electronics and suitable for automotive ECUs, industrial PLC modules, battery-powered medical monitors, and set-top box power management requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX6420UK33+ 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 communications applications.
The MAX6412–MAX6420 family delivers ultra-low-power, capacitor-tunable microprocessor supervisors optimized for dual-voltage monitoring in harsh-environment embedded systems where reliability and footprint efficiency are critical.
FAQ
What is the exact VCC reset threshold voltage for MAX6420UK33+ and how does it vary with temperature?
The MAX6420UK33+ has a factory-trimmed VCC reset threshold of 3.30V nominal, with accuracy of ±1.25% at +25°C and ±2.5% over the full operating range of −40°C to +125°C. This tolerance ensures robust supervision of 3.3V rails even under extreme thermal stress, and the 4mV hysteresis (4 × VTH) prevents chatter near the threshold. The MAX6420UK33+ datasheet specifies these values in the Electrical Characteristics table under "VCC Reset Threshold Accuracy".
How do I configure the adjustable RESET IN input on MAX6420UK33+ to monitor a 1.8V supply?
To monitor a 1.8V rail with the MAX6420UK33+, connect a resistor divider between that rail and ground, with the midpoint feeding the RESET IN pin. Using the formula VMON_TH = 1.26V × (R1 + R2)/R2, select R2 = 1MΩ and solve for R1 ≈ 427kΩ. This yields a threshold of 1.8V ±33mV hysteresis. The MAX6420UK33+ internal 1.26V reference and high-impedance input ensure minimal loading on the monitored rail.
What is the minimum and maximum reset timeout period achievable with MAX6420UK33+ and how is it calculated?
The MAX6420UK33+ reset timeout ranges from 275µs (with CSRT = 0) to 5.75ms (with CSRT = 1500pF at +25°C). The exact period is calculated as tRP = (2.71 × 10⁶) × CSRT + 275µs, where tRP is in seconds and CSRT in farads. For example, a 1nF capacitor yields ~2.99ms. The MAX6420UK33+ datasheet provides the "Reset Timeout Period vs. CSRT" graph and equation in the Typical Operating Characteristics section.
Is MAX6420UK33+ suitable for automotive applications and what qualification does it hold?
The base MAX6420UK33+ is rated for −40°C to +125°C operation and meets industrial reliability standards. Automotive-grade variants-such as MAX6420UK33/V+T-are explicitly AEC-Q100 qualified and marked with /V suffix. These /V versions undergo additional stress testing and screening for automotive use. Always verify the specific part number's ordering information for AEC-Q100 status; the MAX6420UK33+ itself is not automatically automotive-qualified unless ordered with /V.
Why does MAX6420UK33+ use an open-drain RESET output and what pull-up voltage should be used?
The MAX6420UK33+ uses an open-drain RESET output to enable wired-OR reset busing, level translation, and compatibility with µPs having different I/O voltage domains (e.g., 1.8V core, 3.3V I/O). The datasheet specifies RESET can be pulled up to any voltage from 0V to 5.5V. For most applications, a 3.3V or 5V pull-up is standard; the pull-up resistor value (typically 10kΩ) is chosen to balance rise time and power consumption. This design choice is intrinsic to the MAX6420UK33+'s role in mixed-voltage systems.
MAX6420UK33+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Multi-Voltage Supervisor
- Number of Voltages Monitored:
- 2
- Voltage - Threshold:
- 3.3V, 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
MAX6420UK33+ FAQ
1.How can I place an order for MAX6420UK33+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6420UK33+ 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 MAX6420UK33+ reliable?
The price and inventory of MAX6420UK33+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6420UK33+ is usually 5 days.
3.What payment methods are accepted for MAX6420UK33+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6420UK33+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6420UK33+?
MAX6420UK33+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6420UK33+ 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 MAX6420UK33+?
For technical support, including MAX6420UK33+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6420UK33+ requirements.
6.How does Aetrix verify that MAX6420UK33+ is sourced from the original manufacturer or authorized distributors?
All MAX6420UK33+ 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 MAX6420UK33+ meets industry standards.
7.What is the process for return or replacement of MAX6420UK33+?
All MAX6420UK33+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX6420UK33+, 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 MAX6420UK33+ part is unused and in its original packaging.
Return procedure for MAX6420UK33+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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