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Analog Devices Inc./Maxim Integrated MAX6821SUK+T
- Part No.:
- MAX6821SUK+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-74A, SOT-753
- Datasheet:
-
MAX6821SUK+T.pdf
- Description:
- IC MPU SUPERVISOR SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,839
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Product details
Overview
MAX6821SUK+T from Maxim Integrated is a low-voltage microprocessor supervisory IC in SOT23-5 package, providing voltage monitoring (3.08V threshold), 140ms minimum reset timeout, 1.6s watchdog timer, and active-low manual reset input. It asserts push-pull RESET during power-up, brownout, or watchdog timeout, ensuring reliable µP initialization in battery-powered and embedded controllers.
For engineers reviewing the MAX6821SUK+T datasheet, MAX6821SUK+T pinout, MAX6821SUK+T application, or MAX6821SUK+T equivalent, this device serves as a compact, single-chip solution for critical µP monitoring where guaranteed reset validity down to VCC = +1.0V, immunity to short VCC transients, and no external components are required.
Technical Context
The MAX6821SUK+T integrates a precision voltage detector with ±1.5% threshold accuracy over –40°C to +125°C, a monostable reset timer with 140ms–320ms timeout range, and a watchdog circuit that triggers reset if WDI remains static beyond 1.12s–2.60s. Its push-pull RESET output drives high (≥0.8×VCC) when deasserted and low (≤0.3V) when asserted under load up to 3.2mA.
It features internal 50kΩ MR pullup, glitch rejection of 100ns, and MR-to-reset delay of 200ns. The WDI input accepts CMOS-compatible logic levels and tolerates leakage ≤10µA when unconnected, disabling watchdog functionality without external biasing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 3.08V ±1.5% - precisely monitors +3.3V supply rails with hysteresis to prevent chatter during voltage recovery |
| Reset Timeout Period | 140ms min - ensures µP remains held in reset long enough for stable clock and power rail establishment |
| Watchdog Timeout | 1.6s nominal - detects firmware hangs in real-time embedded applications without requiring software polling |
| Operating Voltage Range | +1.2V to +5.5V - supports operation down to 1.2V VCC while guaranteeing valid reset assertion to +1.0V |
| Supply Current | 7–30µA - enables multi-year battery life in portable equipment with negligible quiescent drain |
| RESET Output Type | Push-pull - eliminates need for external pullup resistor and interfaces directly with µP reset pins requiring active-high or active-low assertion |
| MR Input Logic | Active-low with 50kΩ internal pullup - allows momentary switch-to-GND connection without external components or debounce circuitry |
Pinout & Package
MAX6821SUK+T is housed in a RoHS-compliant 5-pin SOT23-5 package (outline U5-1, land pattern 91-0174), measuring 2.9mm × 1.6mm × 1.1mm, suitable for high-density PCB layouts in space-constrained portable and embedded systems.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RESET | Active-low push-pull reset output - drives low during fault conditions and returns high after timeout; sinks up to 3.2mA |
| 2 | GND | Ground reference - shared return path for all internal circuits and external reset loads |
| 3 | MR | Manual reset input - logic-low pulse ≥1µs forces reset; internally pulled up to VCC (50kΩ) |
| 4 | WDI | Watchdog input - toggling within 1.6s clears internal timer; left open disables watchdog function |
| 5 | VCC | Supply and monitor input - powers device and provides reference for voltage detection; monitored for drop below 3.08V |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed reset validity to VCC = +1.0V | Ensures fail-safe reset assertion even during deep brownout or battery depletion, preventing undefined µP behavior |
| No external components required | Reduces BOM count and layout area - all timing, pullup, and detection functions integrated on-die |
| Immunity to short negative VCC transients | Withstands ≤20µs, 100mV-deep glitches without spurious reset, eliminating need for additional filtering capacitors |
| Debounced manual reset input | Internal 100ns glitch rejection and 200ns MR-to-reset delay enable direct switch interface without RC networks |
| 1.6s watchdog timeout with 50ns pulse detection | Enables robust firmware supervision in safety-critical loops where missed instruction execution must trigger recovery |
Applications
| Set-Top Boxes | Portable/Battery-Powered Equipment |
|---|---|
Use Scenario: Power sequencing and crash recovery in digital video receivers subject to unstable AC adapters or cable signal interruptions. IC Role / Device Role / Timing Role: µP supervisor asserting RESET during brownout and watchdog-triggered firmware lockup. Use Value: Prevents corrupted channel tuning or EPG data by enforcing clean reboot before application restart. |
Use Scenario: Long-life handheld instruments powered by coin-cell or Li-ion batteries with gradual voltage decay. IC Role / Device Role / Timing Role: Monitors VCC against 3.08V threshold and guarantees reset until VCC ≥1.0V, enabling graceful shutdown. Use Value: Eliminates data corruption during final battery discharge by holding µP in reset until supply is fully invalid. |
| Embedded Controllers | Critical µP Monitoring |
Use Scenario: Industrial PLC modules operating in wide temperature ranges (–40°C to +125°C) with noisy power rails. IC Role / Device Role / Timing Role: Provides temperature-stable reset threshold (60ppm/°C) and 140ms timeout for deterministic boot. Use Value: Ensures consistent startup timing across environmental extremes without calibration or trimming. |
Use Scenario: Medical or test equipment where µP failure could compromise measurement integrity or user safety. IC Role / Device Role / Timing Role: Dual-fault protection: voltage drop detection + watchdog supervision with independent timeout paths. Use Value: Meets IEC 61508 SIL-2 requirements for hardware fault tolerance via redundant supervision mechanisms. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar µP supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6326UR29+T | Fixed 2.93V threshold, open-drain RESET, no watchdog timer, same SOT23-5 package | Lacks watchdog supervision; suited for simpler reset-only applications without firmware hang detection | Select when only voltage monitoring and manual reset are needed, and board space prohibits adding discrete watchdog logic |
| TPS3808G33DBVR | 3.3V threshold, push-pull RESET, 200ms timeout, no manual reset input, requires external pullup on EN pin for enable control | Omits MR input and uses enable-based activation instead of dedicated reset initiation | Choose when system-level reset coordination is handled externally and manual intervention is unnecessary |
Compared with MAX6821SUK+T, MAX6326UR29+T offers lower cost and smaller footprint but sacrifices watchdog coverage, while TPS3808G33DBVR provides tighter threshold tolerance (±0.5%) yet removes field-serviceable manual reset capability - making MAX6821SUK+T optimal for applications demanding both autonomous fault recovery and operator-initiated reset.
Availability
MAX6821SUK+T is available at Aetrix Electronics and suitable for set-top boxes, portable/battery-powered equipment, and embedded controllers requiring stable component supply across industrial temperature ranges and long production lifecycles.
Supply support for MAX6821SUK+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 precision analog and mixed-signal ICs for power, sensing, and interface applications, with emphasis on reliability and integration for harsh environments.
The MAX6821SUK+T belongs to the MAX682x family of low-voltage µP supervisors, engineered specifically for space-constrained, battery-sensitive systems needing simultaneous voltage monitoring, watchdog supervision, and manual reset in a single SOT23-5 device.
FAQ
What is the exact reset threshold voltage of MAX6821SUK+T?
The MAX6821SUK+T has a factory-trimmed reset threshold of 3.08V, specified with ±1.5% accuracy over –40°C to +125°C. This value corresponds to the "T" suffix in the part number and is validated per the Threshold Suffix Guide in the datasheet. The device holds RESET low until VCC rises above 3.08V and sustains it for ≥140ms thereafter.
Does MAX6821SUK+T include a watchdog timer, and what is its timeout period?
Yes, MAX6821SUK+T includes a watchdog timer with a nominal timeout period of 1.6s. Over temperature, it ranges from 1.12s (min) to 2.60s (max) across –40°C to +125°C. The timer resets on any WDI edge (rising or falling) and is disabled when WDI is left unconnected or three-stated - a feature confirmed in the Pin Description section.
What type of RESET output does MAX6821SUK+T provide, and how is it electrically characterized?
MAX6821SUK+T provides an active-low push-pull RESET output. When asserted, it drives low to ≤0.3V while sinking up to 3.2mA (at VCC ≥ 4.75V). When deasserted, it drives high to ≥0.8×VCC while sourcing up to 800µA. This eliminates external pullup resistors and ensures direct compatibility with µP reset inputs requiring active-low signaling.
Can MAX6821SUK+T operate reliably at very low supply voltages?
Yes, MAX6821SUK+T guarantees valid reset assertion down to VCC = +1.0V, and operates across a full range of +1.2V to +5.5V. Its internal circuitry remains functional and correctly states RESET/RESET outputs even during deep brownout conditions - a key specification verified in the Absolute Maximum Ratings and Electrical Characteristics tables.
Is manual reset supported on MAX6821SUK+T, and how is it implemented?
Yes, MAX6821SUK+T includes an active-low manual reset input (MR) with internal 50kΩ pullup to VCC. A logic-low pulse ≥1µs on MR forces RESET assertion for the full 140ms timeout period. MR requires no external components and accepts CMOS-level signals or momentary switch closure to GND - details confirmed in the Pin Description and Applications Information sections.
MAX6821SUK+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 2.93V
- Output:
- Push-Pull, Totem Pole
- Reset:
- Active High
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
MAX6821SUK+T FAQ
1.How can I place an order for MAX6821SUK+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6821SUK+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 MAX6821SUK+T reliable?
The price and inventory of MAX6821SUK+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6821SUK+T is usually 5 days.
3.What payment methods are accepted for MAX6821SUK+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6821SUK+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6821SUK+T?
MAX6821SUK+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6821SUK+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 MAX6821SUK+T?
For technical support, including MAX6821SUK+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6821SUK+T requirements.
6.How does Aetrix verify that MAX6821SUK+T is sourced from the original manufacturer or authorized distributors?
All MAX6821SUK+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 MAX6821SUK+T meets industry standards.
7.What is the process for return or replacement of MAX6821SUK+T?
All MAX6821SUK+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6821SUK+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 MAX6821SUK+T part is unused and in its original packaging.
Return procedure for MAX6821SUK+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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