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Analog Devices Inc./Maxim Integrated MAX6421XS44+T
- Part No.:
- MAX6421XS44+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-82A, SOT-343
- Datasheet:
-
MAX6421XS44+T.pdf
- Description:
- IC MPU/RESET CIRC 4.375V SC70-4
- Quantity:
- Payment:
- Shipping:
Inventory:3,095
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Product details
Overview
MAX6421XS44+T from Analog Devices is a low-power microprocessor supervisor IC with active-low push-pull reset output, 4.375V nominal reset threshold (±2.5% over temperature), capacitor-adjustable reset timeout (3.0–5.75ms at CSRT = 1500pF), and guaranteed operation down to VCC = 1V. It monitors system supply voltage in portable battery-powered controllers and embedded systems requiring reliable power-on reset assertion.
For engineers reviewing the MAX6421XS44+T datasheet, MAX6421XS44+T pinout, MAX6421XS44+T application, or MAX6421XS44+T equivalent, key selection criteria include its SC70-4 package, 1.6µA typical quiescent current, 80µs VCC-to-reset delay, immunity to short VCC transients, and compatibility with µP reset inputs requiring clean, timed deassertion after brownout recovery.
Technical Context
The MAX6421XS44+T implements a precision voltage-detection circuit with laser-trimmed internal reference and hysteresis (4 × VTH), paired with a 240nA SRT ramp current source that charges an external capacitor to generate a programmable reset timeout. Its push-pull RESET output drives logic-low directly without external pullup.
It operates across -40°C to +125°C, asserts reset when VCC falls below 4.375V (with ±2.5% tolerance over full temperature range), and maintains valid RESET output down to VCC = 1V - enabling robust supervision in deep-brownout conditions common in battery-backed systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.375V nominal (±2.5% over -40°C to +125°C); ensures reliable detection of 5V rail undervoltage before µP malfunction |
| Quiescent Current | 1.6µA typical at VCC ≤ 2.0V; enables multi-year battery life in always-on monitoring applications |
| Reset Timeout Range | 0.275ms (CSRT = 0) to 5.75ms (CSRT = 1500pF); supports µP initialization timing requirements across diverse architectures |
| VCC-to-Reset Delay | 80µs at 1mV/µs VCC fall rate; provides fast response to abrupt supply collapse |
| Operating Voltage Range | 1.0V to 5.5V; allows supervision of Li-ion, NiMH, and regulated 3.3V/5V rails |
| Output Type | Active-low push-pull; eliminates need for external pullup resistor and simplifies PCB layout |
| Package | SC70-4 (X4+1); 1.3mm × 1.6mm footprint ideal for space-constrained portable designs |
Pinout & Package
MAX6421XS44+T is housed in a 4-pin SC70 package (outline 21-0098, land pattern 90-0187), with pins arranged top-view as follows:
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 | VCC | Supply input and reset threshold monitor node; must be decoupled locally to ensure stable detection |
| 2 | GND | Analog ground reference for internal comparator and ramp circuit; requires low-impedance connection to system ground plane |
| 3 | RESET | Active-low push-pull output; directly drives µP reset input without external components |
| 4 | SRT | Set-reset-time input; connects to external capacitor to program timeout period via 240nA constant-current ramp |
Key Features
| Feature | Design Value |
|---|---|
| Capacitor-adjustable reset timeout | Enables precise timing alignment with µP reset hold requirements using a single external capacitor (CSRT) |
| Guaranteed RESET validity to VCC = 1V | Ensures deterministic reset behavior during deep brownout, critical for battery-powered medical and industrial controllers |
| Immunity to short VCC transients | Rejects glitches ≤50µs duration when VCC dips 100mV below threshold, preventing spurious resets |
| Laser-trimmed reset threshold | Delivers ±1.5% accuracy at +25°C and ±2.5% over full temperature range, reducing calibration overhead |
| Low 1.6µA quiescent current | Minimizes standby power draw in always-on supervisory circuits, extending battery service life |
Applications
| Portable Medical Monitors | Battery-Powered Industrial Controllers |
|---|---|
Use Scenario: Continuous ECG or glucose meter operation powered by single-cell Li-ion battery with variable discharge profile. IC Role / Device Role / Timing Role: Supervises 3.3V LDO output; asserts RESET during voltage sag below 4.375V and holds for ≥4ms to guarantee µP cold start. Use Value: Prevents firmware corruption during battery depletion by enforcing minimum reset pulse width aligned to µP datasheet spec. | Use Scenario: Remote sensor node operating on AA alkaline cells with gradual voltage decay over months. IC Role / Device Role / Timing Role: Monitors unregulated 3.0–4.5V supply; triggers reset when cell voltage drops below 4.375V and sustains it until stable restart. Use Value: Eliminates need for discrete RC network while maintaining <2µA total quiescent current for >5-year shelf life. |
| Automotive Body Control Modules | Smart Home Hub Power Sequencing |
Use Scenario: Low-voltage wake-up circuit in BCM during ignition-off battery drain monitoring. IC Role / Device Role / Timing Role: Resets microcontroller if 5V rail sags due to load dump or alternator failure; timeout set to 5.75ms for CAN controller synchronization. Use Value: Provides AEC-Q100-aligned supervision (via family qualification) without adding thermal stress from higher-IQ alternatives. | Use Scenario: Multi-rail power management in voice-controlled hub with 5V USB, 3.3V SoC, and 1.8V memory rails. IC Role / Device Role / Timing Role: Primary supervisor for 5V rail; RESET output sequenced with enable signals to downstream regulators via logic AND gate. Use Value: Push-pull output avoids contention with other open-drain supervisors sharing same reset bus, ensuring clean assertion/deassertion edges. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor reset supervision applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6421US44+T | SOT143-4 package (larger footprint, 1.6mm × 2.1mm vs. SC70's 1.3mm × 1.6mm); identical electrical specs and pinout mapping | Preferred where board assembly uses SOT143-compatible pick-and-place tooling or thermal mass requirements favor larger package | Select MAX6421US44+T only if SC70 placement is not supported; otherwise MAX6421XS44+T offers superior board area efficiency. |
| TLV803SDBZR | Fixed 4.38V threshold (±1%); no capacitor-adjustable timeout (fixed 200ms); 0.5µA IQ; SOT23-3 package | Suitable for cost-sensitive, non-timing-critical applications where long fixed timeout suffices and board space permits SOT23-3 | Choose TLV803SDBZR only when timeout flexibility is unnecessary and ultra-low IQ dominates design priority; MAX6421XS44+T retains programmability and smaller SC70 size. |
Compared with MAX6421US44+T, the MAX6421XS44+T saves 32% PCB area while maintaining identical functionality; versus TLV803SDBZR, it trades 1.1µA higher IQ for 18× tighter timeout adjustability (0.275–5.75ms vs. fixed 200ms) and superior brownout resolution.
Availability
MAX6421XS44+T is available at Aetrix Electronics and suitable for portable medical monitors, battery-powered industrial controllers, and automotive body control modules requiring stable component supply with guaranteed long-term availability.
Supply support for MAX6421XS44+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 semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and control.
The MAX6421XS44+T belongs to the MAX6340/MAX6421–MAX6426 family of low-power µP supervisors, engineered for battery-critical and automotive-grade applications demanding accurate voltage monitoring and flexible reset timing.
FAQ
What is the exact reset threshold voltage of the MAX6421XS44+T?
The MAX6421XS44+T has a nominal reset threshold of 4.375V, with ±1.5% accuracy at +25°C and ±2.5% over the full operating temperature range (-40°C to +125°C). This value is laser-trimmed at wafer test and confirmed in the Electrical Characteristics table under VTH parameter with suffix "44" per Table 1.
Does the MAX6421XS44+T require an external pullup resistor on the RESET pin?
No, the MAX6421XS44+T features an active-low push-pull RESET output, which actively drives both high and low states. Unlike open-drain variants, it does not require an external pullup resistor - simplifying schematic design and reducing BOM count.
How is the reset timeout period set for the MAX6421XS44+T?
The reset timeout period for the MAX6421XS44+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 3.0–5.75ms timeout.
Can the MAX6421XS44+T operate reliably when VCC drops below 2.0V?
Yes, the MAX6421XS44+T guarantees valid RESET output down to VCC = 1.0V, and its supply current remains stable (1.6µA typ at VCC ≤ 2.0V). This enables robust supervision during deep brownout events common in aging battery systems.
What package type is used for the MAX6421XS44+T, and what are its dimensions?
The MAX6421XS44+T uses the SC70-4 package (package code X4+1), measuring 1.3mm × 1.6mm with 0.65mm pitch. Its outline number is 21-0098 and land pattern is 90-0187 - optimized for high-density portable PCB layouts.
MAX6421XS44+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SC-82A, SOT-343
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.375V
- 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
MAX6421XS44+T FAQ
1.How can I place an order for MAX6421XS44+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6421XS44+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 MAX6421XS44+T reliable?
The price and inventory of MAX6421XS44+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6421XS44+T is usually 5 days.
3.What payment methods are accepted for MAX6421XS44+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6421XS44+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6421XS44+T?
MAX6421XS44+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6421XS44+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 MAX6421XS44+T?
For technical support, including MAX6421XS44+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6421XS44+T requirements.
6.How does Aetrix verify that MAX6421XS44+T is sourced from the original manufacturer or authorized distributors?
All MAX6421XS44+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 MAX6421XS44+T meets industry standards.
7.What is the process for return or replacement of MAX6421XS44+T?
All MAX6421XS44+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6421XS44+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 MAX6421XS44+T part is unused and in its original packaging.
Return procedure for MAX6421XS44+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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