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Analog Devices Inc./Maxim Integrated MAX6421US16-T
- Part No.:
- MAX6421US16-T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- TO-253-4, TO-253AA
- Datasheet:
-
MAX6421US16-T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SOT143-4
- Quantity:
- Payment:
- Shipping:
Inventory:7,500
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Product details
Overview
MAX6421US16-T from Maxim Integrated is a low-power microprocessor reset supervisor IC in SOT143-4 package, featuring an active-low push-pull RESET output, 1.575V nominal reset threshold (±2.5% over temperature), capacitor-adjustable reset timeout (275µs minimum), and guaranteed operation down to VCC = 1V. It monitors supply voltages from 1.6V to 5V and is used in battery-powered embedded controllers requiring precise brownout detection and reliable power-up sequencing.
For engineers reviewing the MAX6421US16-T datasheet, MAX6421US16-T pinout, MAX6421US16-T application, or MAX6421US16-T equivalent, key selection criteria include its 1.575V factory-trimmed threshold, 1.6µA typical quiescent current, SC70/SOT143-compatible footprint, push-pull drive capability (3.2mA sink at 4.5V), and immunity to sub-50µs VCC transients when overdriven by 100mV.
Technical Context
The MAX6421US16-T implements a precision voltage comparator with laser-trimmed resistive divider to detect VCC falling below 1.575V, triggering an active-low RESET assertion. Its internal 240nA current source charges an external capacitor on the SRT pin to generate a programmable timeout delay after VCC recovers.
Unlike open-drain variants, the MAX6421US16-T uses a push-pull output stage capable of both sourcing and sinking current-ensuring fast, rail-to-rail RESET transitions without external pullup components. The device remains functional and asserts valid logic states across the full -40°C to +125°C industrial temperature range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 1.575V ±2.5% (factory-trimmed suffix '16'); ensures accurate brownout detection for 1.8V/2.5V systems |
| Quiescent Current | 1.6µA typical at +25°C; enables multi-year battery life in portable medical and sensor nodes |
| Reset Timeout Range | 275µs minimum to >10ms (via 0–15nF SRT capacitor); supports µP initialization timing across ARM Cortex-M and legacy 8-bit MCUs |
| VCC Operating Range | 1.0V to 5.5V; guarantees RESET validity during deep brownout and allows use with Li-ion, coin-cell, and multi-rail systems |
| Output Type | Active-low push-pull; drives RESET directly into CMOS/TTL inputs without pullup resistor or level-shifting |
| VCC to RESET Delay | 80µs max (VCC falling at 1mV/µs); provides deterministic response to rapid supply collapse |
| Transient Immunity | No reset issued for ≤50µs negative VCC glitches ≥100mV below threshold; suppresses noise-induced false resets |
Pinout & Package
MAX6421US16-T is housed in a 4-pin SOT143-4 package (outline 21-0052), measuring 2.1mm × 2.3mm × 0.95mm, with gull-wing leads and RoHS-compliant lead-free finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - GND | Ground reference | Primary return path for internal bias and SRT current source; must be low-impedance connection to system ground plane |
| 2 - RESET | Active-low push-pull output | Drives µP reset input directly; sinks up to 3.2mA at VCC ≥ 4.5V, sources ≥0.8×VCC at 200µA load |
| 3 - SRT | Reset timeout capacitor input | Accepts external capacitor (0–15nF) to set timeout per tRP = 2.73×10⁶×CSRT + 275µs; sensitive to board leakage and stray capacitance |
| 4 - VCC | Supply and threshold monitor input | Monitors system rail; powers internal circuitry and defines reset trip point via trimmed divider; valid down to 1.0V |
Key Features
| Feature | Design Value |
|---|---|
| Capacitor-adjustable reset timeout | Enables precise tailoring of reset hold time (275µs–10ms+) to match specific µP POR requirements without firmware changes |
| 1.6µA ultra-low quiescent current | Reduces standby power in always-on devices-e.g., BLE sensors drawing <1µA average current over 10-year lifetime |
| Guaranteed RESET validity to VCC = 1V | Ensures deterministic reset behavior during deep brownout, critical for fail-safe shutdown in automotive body control modules |
| Immunity to short VCC transients | Eliminates need for additional RC filtering on VCC line, simplifying layout and reducing BOM count in space-constrained wearables |
| Factory-trimmed 1.575V threshold (±2.5%) | Meets tight tolerance requirements for 1.8V I/O domain monitoring without external calibration or trimming resistors |
Applications
| Portable Medical Monitors | Battery-Powered Industrial Controllers |
|---|---|
|
Use Scenario: Continuous glucose monitor operating from CR2032 coin cell with intermittent RF transmission. IC Role / Device Role / Timing Role: Supervises 1.8V analog front-end and 3.3V MCU supply; asserts RESET during battery sag below 1.575V and holds for 5ms to ensure clean restart. Use Value: Prevents corrupted sensor readings and firmware lockup during low-battery operation, extending usable battery life by avoiding premature shutdown. |
Use Scenario: Remote PLC I/O module powered by 3.6V Li-SOCl₂ battery in oil-field telemetry. IC Role / Device Role / Timing Role: Monitors main 3.3V rail and triggers controlled reset if voltage drops due to cold-temperature impedance rise or load surge. Use Value: Maintains data integrity during transient brownouts, eliminating spurious reboots that would interrupt Modbus RTU communication cycles. |
| Automotive Body Electronics | Smart Energy Meters |
|
Use Scenario: Door module with LIN transceiver and EEPROM, exposed to load-dump and cold-crank conditions. IC Role / Device Role / Timing Role: Detects VCC collapse during cranking (down to 1.0V) and asserts RESET until stable 5V rail resumes with 10ms timeout. Use Value: Survives automotive-grade transients without external TVS or LDO, meeting ISO 7637-2 Pulse 4 compliance with minimal external components. |
Use Scenario: Revenue-grade electricity meter with real-time clock and tamper detection, operating from 3.3V backup capacitor. IC Role / Device Role / Timing Role: Watches 3.3V backup rail; initiates graceful RTC save and nonvolatile register freeze before VCC falls below 1.575V. Use Value: Guarantees metrology accuracy and regulatory compliance (IEC 62053) by preventing partial writes to flash during power failure. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor reset supervision applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6421XS16-T | Identical electrical specs and reset threshold, but in 4-pin SC70-4 package (2.0mm × 2.1mm) | Preferred for ultra-dense PCBs where 0.1mm shorter length and 0.2mm narrower width reduce routing congestion | Select when board space is constrained and SC70 reflow compatibility is confirmed |
| TPS3808G16DBVR | Fixed 1.6V threshold (±0.5%), 1.1µA IQ, but requires external R/C for timeout; no SRT pin | Lacks capacitor-adjustable timeout-requires design iteration to tune reset duration via resistor selection | Choose only if tighter threshold accuracy and lower IQ outweigh loss of timeout flexibility and added component count |
Compared with MAX6421US16-T, the SC70 variant offers marginally smaller footprint but identical performance, while the TPS3808G16DBVR trades timeout programmability for improved threshold tolerance and lower quiescent current-making it suitable only when fixed timing and highest accuracy are prioritized over design adaptability.
Availability
MAX6421US16-T is available at Aetrix Electronics and suitable for portable medical monitors, battery-powered industrial controllers, and automotive body electronics requiring stable component supply, long-lifecycle support, and guaranteed RoHS-compliant sourcing.
Supply support for MAX6421US16-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 high-performance analog and mixed-signal semiconductor solutions for industrial, automotive, communications, and consumer markets.
The MAX6421 series belongs to Maxim's precision voltage supervisor product line, engineered specifically for ultra-low-power, capacitor-programmable reset timing in space- and energy-constrained embedded systems.
FAQ
What is the exact reset threshold voltage of MAX6421US16-T?
The MAX6421US16-T has a factory-trimmed nominal reset threshold of 1.575V, with tolerance of ±2.5% over the full -40°C to +125°C temperature range. This value is laser-trimmed during production and confirmed in the Electrical Characteristics table under VTH parameter. The '16' suffix in MAX6421US16-T explicitly denotes this 1.575V threshold per Table 1 of the datasheet.
Can MAX6421US16-T operate with VCC below 1.6V?
Yes, MAX6421US16-T is fully specified to operate down to VCC = 1.0V, and its RESET output remains valid and asserted correctly even at 1.0V. While the General Description states "monitor system voltages from 1.6V to 5V", the Absolute Maximum Ratings and Electrical Characteristics tables confirm guaranteed functionality at 1.0V, including reset assertion and timeout generation-critical for deep brownout recovery.
How do I calculate the external capacitor for a 4.5ms reset timeout using MAX6421US16-T?
Use the formula tRP = 2.73 × 10⁶ × CSRT + 275µs. For tRP = 4.5ms (0.0045s), solve: CSRT = (0.0045 − 0.000275) / 2.73 × 10⁶ = 1548pF. A standard 1500pF ceramic capacitor yields ~4.42ms timeout, verified in Figure MAX6421/26 toc02. Ensure low-leakage (≤10nA) X7R or C0G dielectric.
Is MAX6421US16-T pin-compatible with any other Maxim reset supervisors?
MAX6421US16-T shares the same 4-pin SOT143 pinout with MAX6422US16-T and MAX6423US16-T, differing only in RESET polarity (active-low push-pull vs. active-high push-pull vs. active-low open-drain). No pin-compatible drop-in replacements exist outside the MAX6421/6422/6423 family; MAX6340 and MAX6424–MAX6426 use 5-pin SOT23 and are not pin-compatible.
Does MAX6421US16-T require an external pullup resistor on the RESET pin?
No. MAX6421US16-T features an active-low push-pull RESET output, which actively drives both high and low states. Unlike open-drain variants (e.g., MAX6423US16-T), it does not require an external pullup resistor-reducing component count and eliminating potential timing uncertainty from RC delays on the reset line.
MAX6421US16-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- TO-253-4, TO-253AA
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 1.575V
- 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:
- SOT-23-4
MAX6421US16-T FAQ
1.How can I place an order for MAX6421US16-T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6421US16-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 MAX6421US16-T reliable?
The price and inventory of MAX6421US16-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6421US16-T is usually 5 days.
3.What payment methods are accepted for MAX6421US16-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6421US16-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6421US16-T?
MAX6421US16-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6421US16-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 MAX6421US16-T?
For technical support, including MAX6421US16-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6421US16-T requirements.
6.How does Aetrix verify that MAX6421US16-T is sourced from the original manufacturer or authorized distributors?
All MAX6421US16-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 MAX6421US16-T meets industry standards.
7.What is the process for return or replacement of MAX6421US16-T?
All MAX6421US16-T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6421US16-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 MAX6421US16-T part is unused and in its original packaging.
Return procedure for MAX6421US16-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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