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Analog Devices Inc./Maxim Integrated MAX6421US29+T
- Part No.:
- MAX6421US29+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- TO-253-4, TO-253AA
- Datasheet:
-
MAX6421US29+T.pdf
- Description:
- IC MPU/RESET CIRC 2.925V SOT143
- Quantity:
- Payment:
- Shipping:
Inventory:3,490
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Product details
Overview
MAX6421US29+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 2.925V (typical), with capacitor-adjustable timeout (275µs to >5ms), guaranteed operation down to VCC = 1V, and 1.6µA typical quiescent current - used in battery-powered controllers and portable equipment for reliable power-up/brownout reset control.
For engineers reviewing the MAX6421US29+T datasheet, MAX6421US29+T pinout, MAX6421US29+T application, or MAX6421US29+T equivalent, key selection criteria include its 2.925V reset threshold accuracy (±1.5% at +25°C), SC70-4 package footprint, push-pull RESET output drive capability, and immunity to sub-50µs VCC transients - critical for embedded systems requiring deterministic reset timing under variable supply conditions.
Technical Context
The MAX6421US29+T implements a precision voltage-detection circuit using laser-trimmed resistors to set a fixed 2.925V nominal reset threshold, with ±2.5% tolerance over –40°C to +125°C. Its internal 240nA SRT ramp current charges an external capacitor to generate a programmable reset timeout period.
It features a push-pull RESET output capable of sinking 1.2mA at VCC ≥ 2.7V (VOL ≤ 0.3V) and sourcing 200µA at VCC ≥ 1.8V (VOH ≥ 0.8×VCC), ensuring robust logic-level compatibility with µP reset inputs across 1.6V–5.5V supply ranges.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 2.925V (typ), ±1.5% at +25°C - ensures accurate brownout detection at nominal 2.9V system rails |
| Quiescent Current | 1.6µA (typ) at VCC ≤ 2.0V - enables multi-year battery life in always-on monitoring applications |
| Reset Timeout Range | 275µs to >5ms via external SRT capacitor - supports µP initialization delays from fast-boot to complex firmware load sequences |
| Operating Voltage | 1.0V to 5.5V - guarantees valid RESET assertion even during deep brownout down to 1V supply |
| Output Type | Active-low push-pull - eliminates need for external pullup resistor and drives µP reset input directly |
| Temperature Range | –40°C to +125°C - qualified for automotive under-hood and industrial embedded environments |
| VCC to RESET Delay | 80µs (min) - provides fast response to supply collapse without false triggering on noise |
Pinout & Package
MAX6421US29+T is housed in a 4-pin SC70 package (package code X4+1, outline 21-0098), measuring 1.25mm × 1.25mm × 0.9mm, with wettable flank leads for automated optical inspection. 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 programming input | Accepts 240nA constant current to charge external capacitor; determines reset deassertion delay |
| 2 - GND | Ground reference | Return path for internal bias and reset output stage; must be low-impedance for stable threshold accuracy |
| 3 - RESET | Active-low push-pull reset output | Drives µP reset pin directly; sinks up to 1.2mA while maintaining VOL ≤ 0.3V at VCC ≥ 2.7V |
| 4 - VCC | Supply and monitored voltage input | Power source and voltage sense node; operates and monitors from 1.0V to 5.5V with guaranteed reset validity |
Key Features
| Feature | Design Value |
|---|---|
| Capacitor-adjustable reset timeout | Enables precise tuning of reset hold time (275µs–5.75ms) to match specific µP requirements without firmware changes |
| Guaranteed reset validity to VCC = 1V | Ensures deterministic reset assertion during deep brownout, preventing erratic µP behavior before full power collapse |
| Immunity to short VCC transients | Rejects negative-going glitches ≤ 50µs at 100mV overdrive - avoids spurious resets in noisy power environments |
| Laser-trimmed reset threshold | Delivers ±1.5% accuracy at +25°C and ±2.5% over full temperature range - reduces system-level calibration burden |
| Ultra-low quiescent current | 1.6µA typical at 2.0V supply enables integration into energy-harvesting and coin-cell-powered devices |
Applications
| Battery-Powered Portable Controllers | Automotive Body Control Modules |
|---|---|
Use Scenario: A handheld medical monitor uses a lithium coin cell and requires guaranteed reset during battery voltage sag. IC Role / Device Role / Timing Role: MAX6421US29+T continuously monitors VCC and asserts RESET until voltage recovers above 2.925V and remains stable for programmable timeout. Use Value: Prevents corrupted memory writes and firmware lockup by enforcing clean restart after brownout, extending usable battery life through low 1.6µA ICC. | Use Scenario: An automotive door module powers from a 12V rail conditioned by a DC/DC converter with transient load steps. IC Role / Device Role / Timing Role: MAX6421US29+T detects dips below 2.925V on the 3.3V logic rail and holds µP in reset for ≥3ms to ensure stable power recovery. Use Value: Eliminates microcontroller crashes during load dump or alternator ripple events, meeting AEC-Q100 reliability requirements for passenger safety systems. |
| Industrial Sensor Node Gateways | Medical Infusion Pump Controllers |
Use Scenario: A wireless sensor hub operates on supercapacitor backup during AC mains failure. IC Role / Device Role / Timing Role: MAX6421US29+T monitors the decaying 3.3V rail and triggers controlled shutdown sequence via µP reset before voltage drops below 1.0V. Use Value: Enables graceful data save and state preservation by asserting reset early enough for firmware execution, leveraging guaranteed reset validity down to VCC = 1V. | Use Scenario: A Class II medical device uses dual-redundant µPs requiring synchronized, glitch-immune reset signaling. IC Role / Device Role / Timing Role: MAX6421US29+T provides identical, independently timed reset pulses to both µPs using its push-pull output and low-propagation-delay architecture. Use Value: Ensures deterministic dual-core startup and eliminates race conditions during power recovery, supporting IEC 62304 safety-critical boot requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor reset supervision applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6424UK29+T | Same 2.925V threshold and push-pull output, but in 5-pin SOT23-5 package with N.C. pin instead of SC70-4 | Requires PCB layout change due to different pin count and footprint; no functional difference in reset behavior | Select when SOT23-5 is preferred for assembly compatibility or thermal dissipation needs |
| TLV803EB29DBZR | 2.93V threshold, 0.9µA ICC, open-drain output, no adjustable timeout - fixed 200ms delay | Lacks capacitor-programmable timeout and push-pull drive; requires external pullup and offers less timing flexibility | Choose only if fixed-delay, ultra-low-current operation suffices and board space allows open-drain interface |
Compared with MAX6424UK29+T, the MAX6421US29+T saves board area with its 4-pin SC70 footprint while delivering identical reset accuracy and drive strength; versus TLV803EB29DBZR, it provides design flexibility through adjustable timeout and eliminates external components, at the cost of slightly higher quiescent current.
Availability
MAX6421US29+T is available at Aetrix Electronics and suitable for battery-powered portable controllers, automotive body electronics, and medical infusion pump controllers requiring stable component supply with guaranteed long-term availability and RoHS-compliant packaging.
Supply support for MAX6421US29+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 MAX6421 series belongs to Analog Devices' microprocessor supervisor product line, engineered specifically for ultra-low-power, high-accuracy voltage monitoring and deterministic reset generation in space-constrained, battery-sensitive applications.
FAQ
What is the exact reset threshold voltage of the MAX6421US29+T?
The MAX6421US29+T has a nominal reset threshold of 2.925V, with ±1.5% accuracy at +25°C and ±2.5% over the full –40°C to +125°C operating temperature range. This value is laser-trimmed at wafer test and confirmed in the Electrical Characteristics table of the official datasheet. The "29" suffix in MAX6421US29+T explicitly denotes this 2.925V threshold per Table 1 in the datasheet.
Does the MAX6421US29+T require an external capacitor to function?
The MAX6421US29+T does not require an external capacitor to assert reset - it will trigger immediately upon VCC falling below 2.925V. However, an external capacitor on the SRT pin is required to set the reset timeout period after VCC recovers. Without it, the reset timeout defaults to 275µs (minimum). For applications needing longer hold times (e.g., µP initialization), a capacitor between SRT and GND is mandatory.
Can the MAX6421US29+T operate reliably at VCC = 1.2V?
Yes, the MAX6421US29+T is fully specified to operate and assert valid RESET down to VCC = 1.0V. At 1.2V, its quiescent current is 1.6µA (typ), reset threshold remains accurate within ±2.5%, and RESET output maintains VOL ≤ 0.3V when sinking 50µA. This capability ensures robust brownout protection in deeply undervolted states common in battery-depleted systems.
What package type is used for the MAX6421US29+T and is it RoHS-compliant?
The MAX6421US29+T uses the 4-pin SC70 package (outline 21-0098, land pattern 90-0187), with "+T" denoting tape-and-reel delivery in lead(Pb)-free, RoHS-compliant packaging. The SC70 footprint measures 1.25mm × 1.25mm and supports automated placement and reflow soldering per JEDEC J-STD-020 standards.
How does the MAX6421US29+T handle short voltage transients on the VCC line?
The MAX6421US29+T is designed to reject short negative-going VCC transients: a 100mV dip below the 2.925V threshold lasting ≤50µs typically does not trigger a reset. This immunity is achieved via internal filtering and ramp-based timeout validation, preventing false resets caused by switching noise or load transients - a key advantage over basic comparator-based supervisors.
MAX6421US29+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- TO-253-4, TO-253AA
- Packaging:
- Tape & Reel (TR)
- 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:
- SOT-143-4
MAX6421US29+T FAQ
1.How can I place an order for MAX6421US29+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6421US29+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 MAX6421US29+T reliable?
The price and inventory of MAX6421US29+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6421US29+T is usually 5 days.
3.What payment methods are accepted for MAX6421US29+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6421US29+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6421US29+T?
MAX6421US29+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6421US29+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 MAX6421US29+T?
For technical support, including MAX6421US29+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6421US29+T requirements.
6.How does Aetrix verify that MAX6421US29+T is sourced from the original manufacturer or authorized distributors?
All MAX6421US29+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 MAX6421US29+T meets industry standards.
7.What is the process for return or replacement of MAX6421US29+T?
All MAX6421US29+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6421US29+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 MAX6421US29+T part is unused and in its original packaging.
Return procedure for MAX6421US29+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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