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Analog Devices Inc./Maxim Integrated MAX6421XS22+T
- Part No.:
- MAX6421XS22+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-82A, SOT-343
- Datasheet:
-
MAX6421XS22+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SC70-4
- Quantity:
- Payment:
- Shipping:
Inventory:4,943
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Product details
Overview
MAX6421XS22+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 2.188 V (typical), with capacitor-adjustable timeout (3.0–5.75 ms at CSRT = 1500 pF), guaranteed operation down to VCC = 1 V, and quiescent current of 1.6 µA (typ) - used in battery-powered controllers and portable equipment for reliable power-on reset and brownout protection.
For engineers reviewing the MAX6421XS22+T datasheet, MAX6421XS22+T pinout, MAX6421XS22+T application, or MAX6421XS22+T equivalent, key selection criteria include reset threshold accuracy (±1.5% at +25°C), SRT pin ramp current (240 nA), RESET output drive capability (VOL = 0.3 V at ISINK = 500 µA), temperature range (–40°C to +125°C), and SC70-4 package compatibility.
Technical Context
The MAX6421XS22+T implements a precision voltage-detection circuit with laser-trimmed internal resistors to set its 2.188 V nominal reset threshold, and uses a 240 nA constant-current source charging an external capacitor on the SRT pin to generate a programmable reset timeout delay. Its push-pull RESET output drives low actively and pulls high internally without requiring an external pullup.
It operates across 1.0 V to 5.5 V supply range, maintains valid RESET assertion down to VCC = 1 V, and rejects short VCC transients (e.g., ≤50 µs for 100 mV overdrive), making it suitable for noisy, low-voltage embedded systems where deterministic reset timing and low leakage are critical.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.188 V (typ), ±1.5% at +25°C - sets precise brownout detection point for 2.2 V rail monitoring |
| Quiescent Current | 1.6 µA (typ) at VCC ≤ 2.0 V - enables multi-year battery life in always-on portable devices |
| Reset Timeout Range | 0.275 ms to >6 ms - adjustable via external capacitor (CSRT), supporting µP reset hold times from fast-boot to safety-critical lockout |
| VCC Operating Range | 1.0 V to 5.5 V - ensures functionality during deep brownout and across diverse logic supplies |
| RESET Output Type | Active-low push-pull - eliminates need for external pullup resistor and supports direct interface to CMOS µP reset inputs |
| Temperature Range | –40°C to +125°C - qualified for automotive under-hood and industrial control environments |
| VCC-to-RESET Delay | 80 µs (max) - provides rapid response to supply collapse without false triggering on noise |
Pinout & Package
The MAX6421XS22+T is housed in a 4-pin SC70-4 package (package code X4+1), with 0.65 mm pitch, 1.25 mm × 0.85 mm footprint, and exposed pad not connected - optimized for space-constrained portable PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VCC) | Supply and threshold monitor input | Primary power rail connection; internal voltage divider references this node to generate reset decision |
| 2 (GND) | Ground reference | Analog and digital ground return; must be low-impedance to ensure accurate threshold sensing |
| 3 (SRT) | Reset timeout capacitor input | 240 nA constant-current sink; connects to external timing capacitor to set tRP = 2.73×10⁶ × CSRT + 275 µs |
| 4 (RESET) | Active-low push-pull reset output | Drives µP reset pin directly; sinks ≥500 µA at VOL ≤ 0.3 V, sources ≥200 µA at VOH ≥ 0.8×VCC |
Key Features
| Feature | Design Value |
|---|---|
| Capacitor-adjustable reset timeout | Enables precise tailoring of reset hold time (0.275 ms to >6 ms) without firmware or BOM changes |
| Laser-trimmed reset threshold | Delivers ±1.5% accuracy at +25°C and ±2.5% over –40°C to +125°C - reduces system-level calibration burden |
| Valid RESET down to VCC = 1 V | Ensures deterministic reset assertion during deep undervoltage conditions where most supervisors fail |
| Immunity to short VCC transients | Rejects ≤50 µs glitches at 100 mV overdrive - prevents spurious resets in electrically noisy environments |
| Ultra-low quiescent current | 1.6 µA typical at 2.0 V supply - extends battery runtime in always-on monitoring applications |
Applications
| Battery-Powered Portable Controllers | Automotive Body Control Modules |
|---|---|
Use Scenario: Supervising 2.2 V supply in handheld medical diagnostic device with coin-cell battery. IC Role / Device Role / Timing Role: Voltage monitor and reset generator ensuring safe boot and brownout recovery before MCU execution begins. Use Value: 1.6 µA quiescent current preserves battery life; 2.188 V threshold matches Li-ion discharge curve; SC70-4 footprint saves board area. | Use Scenario: Reset supervision for 2.2 V domain in door module ECU operating across –40°C to +125°C. IC Role / Device Role / Timing Role: Fault-tolerant reset source asserting clean low-going pulse after cold crank or load dump recovery. Use Value: Guaranteed operation to VCC = 1 V prevents latch-up during cranking; ±2.5% threshold stability avoids false resets in thermal cycling. |
| Industrial Sensor Node Transceivers | Low-Voltage Embedded Controllers |
Use Scenario: Monitoring 2.2 V LDO output powering LoRaWAN node MCU and RF front-end. IC Role / Device Role / Timing Role: Supervisor initiating controlled restart after brownout caused by RF transmit current surge. Use Value: Capacitor-adjustable timeout (e.g., 4.375 ms at 1500 pF) aligns with MCU's minimum reset pulse width requirement. | Use Scenario: Reset coordination in energy-harvesting IoT edge controller powered from supercapacitor. IC Role / Device Role / Timing Role: Enabling reliable startup as harvested voltage rises through 2.188 V threshold with no software dependency. Use Value: Push-pull output eliminates external pullup, reducing component count and leakage path in ultra-low-power design. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor reset supervision applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6421US22+T | SOT143-4 package (vs. SC70-4); identical electrical specs and pinout mapping | Larger footprint and 0.95 mm pitch - preferred for manual assembly or thermal relief requirements | Select when board layout allows larger 4-pin SOT143 or requires higher thermal mass |
| TLV803EB22DBZR | Fixed 2.2 V threshold, 200 ms min timeout (non-adjustable), 0.5 µA IQ, SOT23-3 | No SRT pin or timeout adjustment - suitable only for fixed-delay applications with lower current budget | Choose only if timeout flexibility is unnecessary and sub-1 µA IQ is mandatory |
Compared with MAX6421US22+T, the MAX6421XS22+T offers identical functionality in a smaller SC70-4 package but requires tighter layout control around SRT; versus TLV803EB22DBZR, it trades higher IQ for full timeout programmability and wider VCC range (1.0–5.5 V vs. 1.4–5.5 V).
Availability
MAX6421XS22+T is available at Aetrix Electronics and suitable for battery-powered portable controllers, automotive body electronics, and industrial sensor nodes requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for MAX6421XS22+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 MAX6421XS22+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 across automotive, medical, and industrial markets.
FAQ
What is the exact reset threshold voltage of the MAX6421XS22+T?
The MAX6421XS22+T has a nominal reset threshold of 2.188 V, with tolerance of ±1.5% at +25°C and ±2.5% over the full –40°C to +125°C operating range. This value is laser-trimmed at wafer test and corresponds to the "22" suffix in the part number per Table 1 of the datasheet. The MAX6421XS22+T maintains this accuracy without external calibration.
How do I calculate the external capacitor value for a desired reset timeout on the MAX6421XS22+T?
Use the formula CSRT = (tRP – 275 µs) / 2.735 × 10⁶, where tRP is the desired timeout in seconds and CSRT is in farads. For example, a 4.375 ms timeout requires CSRT = (0.004375 – 0.000275) / 2.735 × 10⁶ = 1500 pF. The MAX6421XS22+T's SRT pin sources 240 nA, so low-leakage ceramic capacitors are recommended.
Does the MAX6421XS22+T require an external pullup resistor on the RESET pin?
No, the MAX6421XS22+T features an active-low push-pull RESET output, meaning it actively drives both high and low states internally. Unlike open-drain variants (e.g., MAX6423XS22+T), the MAX6421XS22+T does not require an external pullup resistor - simplifying BOM and eliminating a potential leakage path in ultra-low-power designs.
Can the MAX6421XS22+T operate reliably during cold-crank automotive conditions?
Yes, the MAX6421XS22+T is specified from –40°C to +125°C and guarantees valid RESET assertion down to VCC = 1 V, making it suitable for cold-crank scenarios where battery voltage dips transiently below 6 V. Its immunity to short VCC transients (≤50 µs at 100 mV overdrive) further ensures robustness against cranking noise - though full AEC-Q100 qualification applies only to MAX6340UK31/V+T, not MAX6421XS22+T.
What is the maximum allowable leakage current for the external capacitor connected to the SRT pin of the MAX6421XS22+T?
The external capacitor on the SRT pin of the MAX6421XS22+T must exhibit leakage current less than 10 nA to prevent timing error - ceramic capacitors meet this requirement and are explicitly recommended in the datasheet. Higher-leakage types (e.g., tantalum or electrolytic) will cause extended or inconsistent reset timeout periods, degrading the reliability of the MAX6421XS22+T's supervised reset function.
MAX6421XS22+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:
- 2.188V
- 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
MAX6421XS22+T FAQ
1.How can I place an order for MAX6421XS22+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6421XS22+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 MAX6421XS22+T reliable?
The price and inventory of MAX6421XS22+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6421XS22+T is usually 5 days.
3.What payment methods are accepted for MAX6421XS22+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6421XS22+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6421XS22+T?
MAX6421XS22+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6421XS22+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 MAX6421XS22+T?
For technical support, including MAX6421XS22+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6421XS22+T requirements.
6.How does Aetrix verify that MAX6421XS22+T is sourced from the original manufacturer or authorized distributors?
All MAX6421XS22+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 MAX6421XS22+T meets industry standards.
7.What is the process for return or replacement of MAX6421XS22+T?
All MAX6421XS22+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6421XS22+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 MAX6421XS22+T part is unused and in its original packaging.
Return procedure for MAX6421XS22+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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