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Analog Devices Inc./Maxim Integrated MAX6421XS31+T
- Part No.:
- MAX6421XS31+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-82A, SOT-343
- Datasheet:
-
MAX6421XS31+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SC70-4
- Quantity:
- Payment:
- Shipping:
Inventory:741
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Product details
Overview
The MAX6421XS31+T from Analog Devices is a low-power microprocessor supervisor IC that monitors VCC supply voltage and asserts an active-low push-pull reset signal when voltage falls below 3.075V (typ), with capacitor-adjustable timeout (3.0–5.75ms at CSRT = 1500pF), guaranteed operation down to VCC = 1V, and quiescent current of 1.6µA (typ) - used in battery-powered controllers and portable equipment for reliable power-up sequencing.
For engineers reviewing the MAX6421XS31+T datasheet, MAX6421XS31+T pinout, MAX6421XS31+T application, or MAX6421XS31+T equivalent, key selection criteria include reset threshold accuracy (±2.5% over –40°C to +125°C), SRT pin ramp current (240nA), RESET output low voltage (0.3V at 500µA sink), and SC70-4 package compatibility with space-constrained embedded designs.
Technical Context
This device implements a precision voltage-detection architecture using laser-trimmed resistors and a 0.65V internal reference to compare VCC against a factory-set 3.075V threshold. A 240nA current source charges an external capacitor on the SRT pin to generate a programmable reset timeout delay.
The active-low push-pull RESET output drives logic-compatible loads directly without external pull-up, remains valid for VCC ≥ 1V, and features immunity to transients ≤ 50µs when VCC dips 100mV below threshold - enabling robust brownout detection in noisy automotive and medical environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 3.075V (typ), ±2.5% over –40°C to +125°C - ensures consistent reset assertion across industrial temperature range |
| Reset Timeout Period | 3.00–5.75ms (at CSRT = 1500pF) - provides configurable hold time for µP initialization |
| Supply Current | 1.6µA (typ at VCC ≤ 2.0V) - enables multi-year battery life in portable systems |
| RESET Output Type | Active-low push-pull - eliminates need for external pull-up resistor and supports direct µP reset input drive |
| VCC Operating Range | 1.0V to 5.5V - guarantees reset validity during deep brownout conditions |
| SRT Ramp Current | 240nA (typ) - sets linear capacitor charging rate for accurate timeout calibration |
| RESET Low Voltage | 0.3V at 500µA sink - ensures solid logic-low level for CMOS µP reset inputs |
Pinout & Package
MAX6421XS31+T is housed in a 4-pin SC70-4 package (outline 21-0098), measuring 2.0mm × 2.1mm × 0.95mm, with moisture sensitivity level (MSL) 1 and RoHS-compliant lead-free finish ("+T" suffix).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | VCC | Supply voltage input and monitored rail - must be stable within 1.0V–5.5V for valid reset generation |
| 2 | GND | Analog ground reference - requires low-impedance connection to minimize noise coupling into threshold detection |
| 3 | RESET | Active-low push-pull reset output - sinks up to 500µA while holding <0.3V; no external pull-up needed |
| 4 | SRT | Set-reset-time input - connects to external timing capacitor; sensitive to stray capacitance and leakage (<10nA) |
Key Features
| Feature | Design Value |
|---|---|
| Capacitor-adjustable reset timeout | Enables precise tuning of reset hold time (275µs to >10ms) via single external capacitor - avoids fixed-delay limitations |
| Guaranteed reset validity to VCC = 1V | Ensures deterministic reset behavior during deep undervoltage events where most supervisors fail |
| 240nA SRT ramp current source | Provides stable, temperature-invariant capacitor charging for repeatable timeout accuracy across –40°C to +125°C |
| ±2.5% reset threshold accuracy over full temp range | Reduces system-level margining requirements and improves reliability in critical monitoring applications |
| Immunity to short VCC transients | Rejects glitches ≤50µs duration at 100mV overdrive - prevents spurious resets in electrically noisy environments |
Applications
| Battery-Powered Portable Controllers | Automotive Body Control Modules |
|---|---|
Use Scenario: Supervising microcontrollers in handheld test instruments powered by single-cell Li-ion batteries (2.7–4.2V). IC Role / Device Role / Timing Role: Monitors VCC decay during battery discharge and asserts RESET before µP enters undefined state. Use Value: Prevents firmware corruption during brownout by guaranteeing reset assertion down to 1V and sustaining it for ≥3ms after recovery. |
Use Scenario: Power-on reset generation for LIN bus nodes in door module ECUs exposed to load-dump and cold-crank conditions. IC Role / Device Role / Timing Role: Detects VCC drop below 3.075V during cranking and holds µP in reset until stable supply resumes. Use Value: Eliminates need for external RC network while maintaining AEC-Q100-aligned reliability through 125°C operation. |
| Medical Patient Monitoring Devices | Industrial Embedded Controllers |
Use Scenario: Ensuring safe startup of ARM-based vital-sign processors in portable ECG units with dual-supply rails. IC Role / Device Role / Timing Role: Provides clean, glitch-free reset pulse synchronized to main 3.3V rail with no false triggers from EMI. Use Value: Meets IEC 60601-1 safety requirements via guaranteed reset validity and transient immunity up to 50µs. |
Use Scenario: Reset supervision for RISC-V SoCs in DIN-rail mounted PLCs operating in wide-temperature industrial cabinets. IC Role / Device Role / Timing Role: Acts as primary power-good monitor for 3.3V core supply, interfacing directly to SoC's nRST pin. Use Value: Enables compact layout with SC70-4 footprint and eliminates BOM cost of discrete reset IC + timing components. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor reset supervision applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6421US31+T | SOT143-4 package (vs. SC70-4); identical electrical specs and pinout | Larger footprint (2.9mm × 1.6mm vs. 2.0mm × 2.1mm); higher thermal resistance | Select when board assembly uses SOT143 pick-and-place tooling or requires slightly higher power dissipation margin |
| TLV803EB31DBVR | Fixed 3.08V threshold; 200ms min timeout (non-adjustable); 0.5µA IQ | No external capacitor required; less flexible timing but lower component count | Choose for cost-sensitive, space-constrained designs where fixed timeout suffices and ultra-low IQ is prioritized |
Compared with MAX6421XS31+T, the MAX6421US31+T offers identical functionality in a larger SOT143 package suitable for manual rework or thermal-heavy layouts, while the TLV803EB31DBVR trades adjustable timeout for lower quiescent current and zero external components - making it preferable only when timing flexibility is unnecessary.
Availability
MAX6421XS31+T is available at Aetrix Electronics and suitable for battery-powered portable controllers, automotive body control modules, and medical patient monitoring devices requiring stable component supply with guaranteed long-term availability.
Supply support for MAX6421XS31+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
Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets since 1965.
The MAX6421XS31+T belongs to the MAX6340/MAX6421–MAX6426 family of low-power µP supervisors designed specifically for reliable reset generation in space- and power-constrained embedded systems operating across –40°C to +125°C.
FAQ
What is the exact reset threshold voltage of the MAX6421XS31+T?
The MAX6421XS31+T has a nominal reset threshold of 3.075V (typical), with a guaranteed range of 2.998V to 3.152V at +25°C and ±2.5% tolerance over –40°C to +125°C. This value is laser-trimmed at wafer test and confirmed per Table 1 in the datasheet - the "31" suffix explicitly denotes this threshold grade.
Does the MAX6421XS31+T require an external pull-up resistor on the RESET pin?
No, the MAX6421XS31+T features an active-low push-pull RESET output, meaning it actively drives both high and low states. Unlike open-drain variants (e.g., MAX6423), it does not require an external pull-up resistor - simplifying BOM and eliminating risk of weak pull-up causing slow rise times or logic ambiguity.
How is the reset timeout period set for the MAX6421XS31+T?
The reset timeout period of the MAX6421XS31+T is set by connecting an external capacitor (CSRT) between the SRT pin and GND. The relationship is tRP = (2.73 × 10⁶ × CSRT) + 275µs, where tRP is in seconds and CSRT in farads. For example, a 1500pF capacitor yields 3.00–5.75ms timeout depending on process variation.
Can the MAX6421XS31+T operate reliably below 1.6V supply voltage?
Yes - the MAX6421XS31+T is fully specified down to VCC = 1.0V, with guaranteed RESET assertion and deassertion behavior. Its ability to maintain valid reset signaling down to 1V (per Electrical Characteristics table) makes it suitable for ultra-low-voltage brownout detection in energy-harvesting and coin-cell applications where other supervisors fail.
What package type and dimensions does the MAX6421XS31+T use?
The MAX6421XS31+T uses the SC70-4 package (package code X4+1, outline 21-0098), measuring 2.0mm × 2.1mm × 0.95mm with a 0.65mm pitch. It is RoHS-compliant, lead-free ("+T" suffix), and rated MSL1 - compatible with standard reflow profiles and suitable for high-density PCB layouts.
MAX6421XS31+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SC-82A, SOT-343
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 3.075V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active Low
- Reset Timeout:
- Adjustable/Selectable
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SC-70-4
MAX6421XS31+T FAQ
1.How can I place an order for MAX6421XS31+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6421XS31+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 MAX6421XS31+T reliable?
The price and inventory of MAX6421XS31+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6421XS31+T is usually 5 days.
3.What payment methods are accepted for MAX6421XS31+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6421XS31+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6421XS31+T?
MAX6421XS31+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6421XS31+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 MAX6421XS31+T?
For technical support, including MAX6421XS31+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6421XS31+T requirements.
6.How does Aetrix verify that MAX6421XS31+T is sourced from the original manufacturer or authorized distributors?
All MAX6421XS31+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 MAX6421XS31+T meets industry standards.
7.What is the process for return or replacement of MAX6421XS31+T?
All MAX6421XS31+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6421XS31+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 MAX6421XS31+T part is unused and in its original packaging.
Return procedure for MAX6421XS31+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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