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Analog Devices Inc./Maxim Integrated MAX6421XS29
- Part No.:
- MAX6421XS29
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-82A, SOT-343
- Datasheet:
-
MAX6421XS29.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SC70-4
- Quantity:
- Payment:
- Shipping:
Inventory:1,331
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Product details
Overview
MAX6421XS29 from Maxim Integrated is a low-power, active-low push-pull microprocessor reset supervisor IC designed for precise VCC monitoring and capacitor-adjustable reset timeout in space-constrained systems. It monitors supply voltages from 1.6V to 5V with a factory-trimmed reset threshold of 2.925V (±2.5%), asserts reset for a user-defined timeout (275µs to >10ms), and guarantees valid operation down to VCC = 1V. It is used in battery-powered controllers and portable equipment requiring reliable power-on reset sequencing.
For engineers reviewing the MAX6421XS29 datasheet, MAX6421XS29 pinout, MAX6421XS29 application, or MAX6421XS29 equivalent, key selection criteria include its SC70-4 package, 1.6µA typical quiescent current, push-pull active-low RESET output, capacitor-programmable timeout, and guaranteed reset validity at VCC ≥ 1V - critical for ultra-low-power embedded designs.
Technical Context
The MAX6421XS29 implements a precision voltage comparator with laser-trimmed internal reference to detect VCC falling below 2.925V, triggering an immediate active-low reset assertion. Its reset timeout is generated by a 240nA internal ramp current charging an external capacitor (CSRT) to a 0.65V threshold, enabling accurate, temperature-stable delay control independent of VCC.
This device operates across –40°C to +125°C and features immunity to short VCC transients (e.g., ≤50µs for 100mV overdrive), hysteresis of 4×VTH (≈11.7mV), and guaranteed reset assertion during power-up/power-down/brownout conditions - all while consuming only 1.6µA at +25°C and VCC ≤ 2.0V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.925V ±2.5% (factory-trimmed suffix '29'); ensures reliable detection of brownout at nominal 3.0V rails. |
| Quiescent Current | 1.6µA typ (VCC ≤ 2.0V); enables multi-year battery life in always-on monitoring applications. |
| Reset Timeout Range | 275µs minimum (CSRT = 0) to >10ms (CSRT = 10nF); supports µP initialization timing across diverse architectures. |
| Output Type | Active-low push-pull; drives RESET directly without external pullup, simplifying PCB layout and reducing BOM count. |
| VCC Validity Range | RESET guaranteed valid down to VCC = 1V; ensures deterministic behavior during deep brownout recovery. |
| Hysteresis | 4 × VTH ≈ 11.7mV; prevents chatter near threshold during slow-rising/falling VCC transitions. |
| Supply Voltage Range | 1.0V to 5.5V; supports operation across 1.2V, 1.8V, 2.5V, 3.3V, and 5.0V logic domains. |
Pinout & Package
MAX6421XS29 is housed in a 4-pin SC70-4 package (outline 21-0098), footprint-compatible with SOT143-4 but with smaller 1.3mm × 1.0mm body and 0.65mm pitch. Pin 1 is SRT (Set Reset Timeout), Pin 2 is GND, Pin 3 is RESET (active-low push-pull), and Pin 4 is VCC.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - SRT | Reset timeout capacitor input | Accepts external capacitor (CSRT) to set timeout period per tRP = 2.73×10⁶ × CSRT + 275µs; requires low-leakage ceramic cap. |
| 2 - GND | Ground reference | Primary return path for internal bias and ramp current; must be low-impedance to ensure timeout accuracy. |
| 3 - RESET | Active-low push-pull reset output | Drives µP reset input low during fault; sinks up to 3.2mA at VCC ≥ 4.5V (VOL ≤ 0.4V); no external pullup needed. |
| 4 - VCC | Supply and monitored voltage input | Power source and reset threshold reference; monitors system rail from 1.0V–5.5V; resets when VCC falls below 2.925V. |
Key Features
| Feature | Design Value |
|---|---|
| Capacitor-adjustable reset timeout | Enables precise, application-specific reset hold time (275µs–10ms+) without firmware or external timers. |
| Ultra-low quiescent current | 1.6µA typical at VCC ≤ 2.0V reduces standby power in battery-critical systems like medical wearables. |
| Guaranteed reset validity to VCC = 1V | Ensures deterministic reset assertion during deep undervoltage events, preventing runaway µP execution. |
| Immunity to short VCC transients | Rejects glitches ≤50µs at 100mV overdrive, eliminating false resets in noisy automotive or industrial environments. |
| Laser-trimmed reset threshold | 2.925V ±2.5% tolerance eliminates need for external resistor dividers or calibration in production. |
Applications
| Portable Medical Sensors | Battery-Powered Industrial Controllers |
|---|---|
Use Scenario: Continuous glucose monitor with coin-cell battery and ARM Cortex-M0+ MCU. IC Role / Device Role / Timing Role: Monitors 3.0V LDO output and asserts reset if voltage sags below 2.925V during RF transmission burst. Use Value: Prevents corrupted sensor data logging by ensuring MCU restarts cleanly after brownout, leveraging 1.6µA supply current to extend battery life beyond 2 years. |
Use Scenario: Remote PLC I/O module powered by 3.6V Li-SOCl₂ battery in oil-field telemetry. IC Role / Device Role / Timing Role: Provides 5ms reset timeout to allow analog front-end settling before MCU boot sequence begins. Use Value: Guarantees full system initialization under cold-start (-40°C) conditions where VCC ramps slowly, using SC70-4 footprint to minimize board area. |
| Automotive Body Control Modules | Smart Energy Meters |
Use Scenario: Door module with CAN interface and 5V supply derived from vehicle battery. IC Role / Device Role / Timing Role: Detects load-dump-induced dips on 5V rail and holds MCU in reset until stable, with transient immunity up to 50µs. Use Value: Eliminates spurious CAN bus errors caused by µP instability during ignition transients, meeting AEC-Q100 Class 0 requirements via -40°C to +125°C operation. |
Use Scenario: Two-way AMI meter with real-time clock, metrology ASIC, and 3.3V supply. IC Role / Device Role / Timing Role: Monitors 3.3V rail and provides 275µs minimum reset pulse to meet metrology ASIC power-on timing spec. Use Value: Ensures RTC and flash memory initialize correctly after power restoration, using push-pull output to drive multiple downstream reset inputs without signal degradation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor reset supervision applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6421US29-T | SOT143-4 package (larger than SC70-4); identical electrical specs and pinout mapping. | Preferred where thermal dissipation or hand-soldering reliability outweighs size constraints. | Select MAX6421US29-T for manual assembly or higher thermal mass requirements; same functionality, different footprint. |
| TLV809K30DBZR | Fixed 3.0V threshold (not adjustable), 2.5µA IQ, SOT23-3 package, no capacitor-based timeout. | Suitable only for fixed-timing, cost-sensitive applications without programmable delay needs. | Choose TLV809K30DBZR only if reset timeout is fixed and board space allows SOT23-3; lacks timeout adjustability and SC70 size. |
Compared with MAX6421XS29, MAX6421US29-T offers identical performance in a larger, more robust package, while TLV809K30DBZR sacrifices timeout flexibility and ultra-low IQ for lower unit cost and simpler implementation - making MAX6421XS29 optimal for size- and power-constrained designs requiring precise, user-defined reset hold times.
Availability
MAX6421XS29 is available at Aetrix Electronics and suitable for portable medical sensors, battery-powered industrial controllers, and automotive body control modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.
Supply support for MAX6421XS29 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 power, sensing, and interface applications in industrial, automotive, and medical markets.
The MAX6421–MAX6426 family delivers ultra-low-power, capacitor-programmable reset supervision for battery-operated and space-constrained systems - targeting applications where deterministic power-on reset, minimal quiescent current, and flexible timeout control are essential.
FAQ
What is the factory-trimmed reset threshold voltage of MAX6421XS29?
The MAX6421XS29 has a factory-trimmed reset threshold of 2.925V, with ±2.5% accuracy over the full –40°C to +125°C temperature range. This value corresponds to the '29' suffix in the part number and is laser-trimmed during production to eliminate external resistor networks and ensure consistent brownout detection across units.
How is the reset timeout period set for MAX6421XS29?
The reset timeout period for MAX6421XS29 is set by connecting an external capacitor (CSRT) between the SRT pin and ground. The relationship is tRP = (2.73 × 10⁶) × CSRT + 275µs, where tRP is in seconds and CSRT is in farads. A 1500pF capacitor yields ~4.375ms timeout, and ceramic capacitors with leakage <10nA are recommended for stability.
Does MAX6421XS29 require an external pullup resistor on the RESET pin?
No, MAX6421XS29 does not require an external pullup resistor because it features an active-low push-pull RESET output. The internal driver actively pulls the line low during reset and high when deasserted, eliminating the need for external components and simplifying layout - unlike open-drain variants such as MAX6423XS29.
What is the minimum supply voltage at which MAX6421XS29 guarantees valid RESET operation?
MAX6421XS29 guarantees valid RESET assertion and deassertion down to VCC = 1.0V. Below this voltage, output drive capability degrades significantly. This specification ensures reliable reset behavior during deep brownout recovery in ultra-low-voltage systems, such as those powered by single-cell Li-ion or alkaline batteries.
Can MAX6421XS29 be used in automotive applications?
Yes, MAX6421XS29 is rated for –40°C to +125°C operation and is suitable for automotive body electronics applications such as door modules and lighting controllers. While the standard MAX6421XS29 is not AEC-Q100 qualified, automotive-grade versions (e.g., MAX6421XS29/V+) are available - confirm qualification status with Aetrix Electronics for mission-critical deployments.
MAX6421XS29 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:
- 2.925V
- 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
MAX6421XS29 FAQ
1.How can I place an order for MAX6421XS29 through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6421XS29 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 MAX6421XS29 reliable?
The price and inventory of MAX6421XS29 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6421XS29 is usually 5 days.
3.What payment methods are accepted for MAX6421XS29?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6421XS29 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6421XS29?
MAX6421XS29 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6421XS29 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 MAX6421XS29?
For technical support, including MAX6421XS29 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6421XS29 requirements.
6.How does Aetrix verify that MAX6421XS29 is sourced from the original manufacturer or authorized distributors?
All MAX6421XS29 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 MAX6421XS29 meets industry standards.
7.What is the process for return or replacement of MAX6421XS29?
All MAX6421XS29 units undergo pre-shipment inspection (PSI). If there is an issue with MAX6421XS29, 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 MAX6421XS29 part is unused and in its original packaging.
Return procedure for MAX6421XS29:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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