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Analog Devices Inc./Maxim Integrated MAX6821TUK+
- Part No.:
- MAX6821TUK+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-74A, SOT-753
- Datasheet:
-
MAX6821TUK+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:4,769
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Product details
Overview
MAX6821TUK+ from Maxim Integrated is a low-voltage microprocessor supervisory IC in 5-pin SOT23 package, combining voltage monitoring (3.08V threshold), 140ms minimum reset timeout, 1.6s watchdog timer, manual reset input, and push-pull active-low RESET output. It ensures reliable µP startup and brownout recovery in portable equipment and embedded controllers.
For engineers reviewing the MAX6821TUK+ datasheet, MAX6821TUK+ pinout, MAX6821TUK+ application, or MAX6821TUK+ equivalent, this device supports critical power-on sequencing, code-execution error detection via watchdog, and noise-immune manual reset-key for battery-powered instrumentation and set-top boxes requiring guaranteed reset validity down to VCC = +1.0V.
Technical Context
The MAX6821TUK+ 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 internal 50kΩ MR pullup enables direct switch-to-GND connection without external components.
Reset assertion occurs on VCC fall below 3.08V (±1.5%), MR low, or WDI timeout; RESET remains asserted for ≥140ms after VCC recovery, MR release, or watchdog trigger. The push-pull output drives low to ≤0.3V at 500µA sink and high to ≥0.8×VCC at 200µA source, ensuring robust interface with µP reset pins.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 3.08V ±1.5% - precisely monitors +3.3V supply rails during brownout conditions |
| Reset Timeout Period | 140ms min - guarantees µP remains held in reset long enough for stable power rail settling |
| Watchdog Timeout | 1.6s nominal (1.12–2.60s over temp) - detects firmware hangs in real-time embedded loops |
| Supply Current | 7–30µA - enables multi-year operation in battery-powered equipment |
| Operating Voltage Range | +1.2V to +5.5V - supports wide-input systems including Li-ion and multi-rail designs |
| Reset Output Type | Push-pull active-low - eliminates need for external pullup resistor; compatible with standard µP reset inputs |
| VCC Reset Validity | Down to +1.0V - ensures deterministic reset behavior even during deep undervoltage events |
Pinout & Package
Package: 5-pin SOT23-5 (U5-1 outline), footprint-compatible with industry-standard 5-lead SOT-23 layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RESET | Active-low push-pull reset output; asserts low on VCC drop, MR low, or watchdog timeout |
| 2 | GND | Ground reference for all internal circuits and reset timing accuracy |
| 3 | MR | Active-low manual reset input with internal 50kΩ pullup; debounced by 140ms timeout |
| 4 | WDI | Watchdog input; toggling within 1.6s resets internal timer; unconnected disables watchdog |
| 5 | VCC | Supply voltage and monitored rail input; powers device and sets reset threshold reference |
Key Features
| Feature | Design Value |
|---|---|
| No external components required | Integrated 50kΩ MR pullup, precision voltage reference, and monostable timers eliminate BOM cost and layout area |
| Guaranteed reset validity to VCC = +1.0V | Ensures predictable reset state during deep brownouts where other supervisors fail silently |
| Immunity to short negative VCC transients | Withstands ≤20µs glitches down to 100mV below threshold without spurious reset assertion |
| 1.6s watchdog with 50ns pulse detection | Detects stalled firmware execution while tolerating brief I/O noise on WDI line |
| Five-temperature-range qualification | Specified from –40°C to +125°C with production-tested parameters, not just design-guaranteed |
Applications
| Set-Top Boxes | Portable/Battery-Powered Equipment |
|---|---|
Use Scenario: Power cycling during firmware updates and HDMI hot-plug events. IC Role / Device Role / Timing Role: Supervisory IC asserting controlled reset to prevent corrupted flash writes and ensure clean boot sequence. Use Value: 140ms reset timeout prevents premature µP release before power rails stabilize post-update. |
Use Scenario: Long-term operation on single-cell Li-ion batteries with gradual voltage decay. IC Role / Device Role / Timing Role: Voltage monitor and watchdog enforcing safe shutdown before brownout-induced data corruption. Use Value: 3.08V threshold aligns with +3.3V system rail; reset valid to +1.0V enables last-chance recovery before cutoff. |
| Embedded Controllers | Intelligent Instruments |
Use Scenario: Industrial control nodes operating in electrically noisy environments. IC Role / Device Role / Timing Role: Manual reset input (MR) and watchdog jointly guard against EMI-induced lockups. Use Value: Debounced MR with 140ms hold time rejects contact bounce; watchdog detects silent firmware freezes. |
Use Scenario: Precision measurement instruments requiring deterministic initialization after power-on. IC Role / Device Role / Timing Role: Supervisor ensuring µP enters known state only after analog references and ADCs stabilize. Use Value: Push-pull RESET provides fast, low-impedance drive to meet tight µP reset setup/hold timing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6326UT463+T | Fixed 4.63V reset threshold; no watchdog or manual reset; open-drain RESET | Suitable only for simple power-fail detection without runtime supervision | Select when watchdog and MR functions are unnecessary and higher reset threshold is acceptable |
| TPS3808G33DBVR | 3.3V threshold; 200ms reset timeout; no manual reset; push-pull RESET; requires external capacitor for watchdog | Lacks integrated MR and fixed watchdog period; higher quiescent current (12µA vs. 7µA) | Choose for TI-based designs where ecosystem compatibility outweighs feature parity |
Compared with MAX6821TUK+, MAX6326UT463+T omits watchdog and MR-reducing supervision capability but simplifying design-while TPS3808G33DBVR offers tighter threshold tolerance (0.5%) but sacrifices MR integration and adds external component dependency.
Availability
MAX6821TUK+ 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 product lifecycles.
Supply support for MAX6821TUK+ 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 demanding industrial, computing, and communications applications.
The MAX6821TUK+ belongs to the MAX682x family of low-voltage µP supervisors, engineered specifically for reliable power-up sequencing, brownout protection, and runtime fault detection in space-constrained embedded systems.
FAQ
What is the exact reset threshold voltage of the MAX6821TUK+?
The MAX6821TUK+ has a factory-trimmed reset threshold of 3.08V with ±1.5% accuracy over the full –40°C to +125°C temperature range. This value is confirmed in the Threshold Suffix Guide where "T" corresponds to 3.08V, and is validated in the Electrical Characteristics table under VTH for MAX682_T.
Does the MAX6821TUK+ include a watchdog timer and manual reset input?
Yes, the MAX6821TUK+ includes both a 1.6s nominal watchdog timer (with 1.12s–2.60s range over temperature) and an active-low manual reset input (MR) with internal 50kΩ pullup. These features are explicitly listed in the Selector Guide and Pin Description for MAX6821, distinguishing it from MAX6824/MAX6825 variants.
What is the function of the WDI pin on the MAX6821TUK+?
The WDI (Watchdog Input) pin on the MAX6821TUK+ must be toggled low-to-high or high-to-low at least once every 1.6s to prevent watchdog timeout. If WDI remains static beyond that period, the device asserts RESET for the full reset timeout duration. Leaving WDI unconnected disables the watchdog function entirely.
Is the RESET output of the MAX6821TUK+ push-pull or open-drain?
The MAX6821TUK+ features a push-pull active-low RESET output, as confirmed in the Selector Guide and Pin Configurations section. This differs from the MAX6822 (open-drain) and MAX6823 (push-pull active-high), and eliminates the need for an external pullup resistor when interfacing with standard µP reset inputs.
What is the minimum VCC voltage at which the MAX6821TUK+ guarantees correct RESET output state?
The MAX6821TUK+ guarantees correct RESET output state down to VCC = +1.0V, as stated in the General Description and verified in the Absolute Maximum Ratings and Electrical Characteristics sections. This ensures deterministic reset behavior during deep undervoltage conditions where many competitors fail.
MAX6821TUK+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 3.08V
- 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
MAX6821TUK+ FAQ
1.How can I place an order for MAX6821TUK+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6821TUK+ 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 MAX6821TUK+ reliable?
The price and inventory of MAX6821TUK+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6821TUK+ is usually 5 days.
3.What payment methods are accepted for MAX6821TUK+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6821TUK+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6821TUK+?
MAX6821TUK+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6821TUK+ 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 MAX6821TUK+?
For technical support, including MAX6821TUK+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6821TUK+ requirements.
6.How does Aetrix verify that MAX6821TUK+ is sourced from the original manufacturer or authorized distributors?
All MAX6821TUK+ 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 MAX6821TUK+ meets industry standards.
7.What is the process for return or replacement of MAX6821TUK+?
All MAX6821TUK+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX6821TUK+, 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 MAX6821TUK+ part is unused and in its original packaging.
Return procedure for MAX6821TUK+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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