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Analog Devices Inc./Maxim Integrated MAX6821LUK+T
- Part No.:
- MAX6821LUK+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-74A, SOT-753
- Datasheet:
-
MAX6821LUK+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:2,500
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Product details
Overview
MAX6821LUK+T from Maxim Integrated is a low-voltage microprocessor supervisory IC in 5-pin SOT23 package, combining voltage monitoring (4.63V reset threshold), 140ms minimum reset timeout, 1.6s watchdog timer, manual reset input, and push-pull RESET output. It ensures reliable power-up/power-down sequencing and brownout protection for embedded controllers and battery-powered equipment.
For engineers reviewing the MAX6821LUK+T datasheet, MAX6821LUK+T pinout, MAX6821LUK+T application, or MAX6821LUK+T equivalent, this device serves as a precision reset supervisor with guaranteed reset validity down to VCC = +1.0V, immunity to short negative VCC transients, and no external components required.
Technical Context
The MAX6821LUK+T integrates a precision voltage comparator with 60ppm/°C temperature coefficient, a monostable reset timeout generator (140–320ms over temperature), and a watchdog timer with 1.12–2.60s timeout range. Its internal 50kΩ MR pullup enables direct switch-to-GND connection without external biasing.
It features dual active-reset outputs: push-pull RESET (active-low) and push-pull RESET (active-high), both asserted simultaneously during VCC undervoltage, MR assertion, or watchdog timeout. Reset deassertion occurs only after VCC exceeds 4.63V and the 140ms timeout elapses.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.63V ±30mV at -40°C to +125°C - sets precise brownout detection point for +5V systems |
| Reset Timeout Period | 140ms (min) - ensures µP remains held in reset long enough for stable power rail recovery |
| Watchdog Timeout | 1.6s nominal (1.12–2.60s over temp) - provides robust software execution monitoring |
| VCC Operating Range | +1.2V to +5.5V - supports operation during deep brownout while maintaining valid reset state |
| RESET Output Type | Push-pull active-low - drives low without external pullup, compatible with standard µP reset inputs |
| MR Input Logic | Active-low with 50kΩ internal pullup - eliminates need for external resistor; accepts CMOS-level signals |
| Supply Current | 30µA max at -40°C to +125°C - enables ultra-low-power operation in portable equipment |
Pinout & Package
Package: 5-pin SOT23-5 (U5-1 outline, land pattern 21-0057), RoHS-compliant, -40°C to +125°C operating range.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RESET (active-low) | Push-pull output asserted low during VCC < 4.63V, MR low, or watchdog timeout - directly drives µP reset pin |
| 2 | GND | Ground reference for all internal comparators and timers - must be low-impedance return path |
| 3 | MR (manual reset) | Active-low input with internal 50kΩ pullup to VCC - momentary GND connection initiates system reset |
| 4 | WDI (watchdog input) | Edge-sensitive input that clears 1.6s timer on rising/falling transition - left unconnected to disable watchdog |
| 5 | VCC | Supply and monitored voltage rail - powers device and feeds reset threshold comparator |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed reset validity to VCC = +1.0V | Ensures deterministic reset behavior even during severe brownout conditions where other supervisors fail |
| Immunity to short negative VCC transients | Withstands ≤20µs glitches down to 100mV below threshold without spurious reset - reduces false triggers in noisy environments |
| No external components required | Eliminates BOM cost and board space for pullups, RC networks, or discrete timing elements |
| Dual reset outputs (RESET and RESET) | Simultaneous active-low and active-high signals simplify interface to mixed-logic µPs or FPGA reset controllers |
| Debounced manual reset input | Internal filtering removes switch bounce; no external capacitor needed unless operating in high-noise industrial settings |
Applications
| Set-Top Boxes | Embedded Controllers |
|---|---|
Use Scenario: Power sequencing and firmware recovery during AC mains interruption or cold boot. IC Role / Device Role / Timing Role: Voltage monitor and watchdog supervisor asserting reset until +5V rail stabilizes above 4.63V and software confirms health. Use Value: Prevents corrupted channel tuning or HDMI handshake failures by enforcing clean restart after brownout. |
Use Scenario: Industrial PLC modules requiring deterministic startup and runtime fault recovery. IC Role / Device Role / Timing Role: Dual-role supervisor providing both power-on reset and software hang detection via WDI toggling. Use Value: Enables autonomous recovery from frozen ladder logic execution without operator intervention. |
| Portable/Battery-Powered Equipment | Critical µP Monitoring |
Use Scenario: Wearable medical sensors operating from single-cell Li-ion with declining voltage profile. IC Role / Device Role / Timing Role: Low-quiescent-current (30µA max) supervisor monitoring VCC down to +1.2V while guaranteeing reset assertion to +1.0V. Use Value: Extends usable battery life by enabling safe shutdown before data corruption occurs at low voltage. |
Use Scenario: Aerospace avionics subsystems where single-event upsets may halt µP execution. IC Role / Device Role / Timing Role: Watchdog timer with 1.6s timeout and glitch-immune MR input serving as last-resort recovery mechanism. Use Value: Meets DO-254 functional safety requirements by ensuring reset within bounded time after software stall. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar µP supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6822LUK+T | Open-drain RESET output instead of push-pull; identical threshold, timeout, and watchdog specs | Required when interfacing with bidirectional µP reset pins (e.g., Motorola 68HC11) needing external pullup | Select MAX6822LUK+T only if open-drain drive and external pullup are part of existing schematic design |
| TPS3808G33DBVR | 3.3V fixed threshold, 200ms reset timeout, no manual reset input, same SOT23-5 package | Lacks MR and WDI functions - suitable only for basic voltage monitoring without user-initiated or software-monitored reset | Choose TPS3808G33DBVR only when watchdog and manual reset features are unnecessary and 3.3V threshold suffices |
Compared with MAX6821LUK+T, MAX6822LUK+T offers identical supervision functionality but requires an external pullup for RESET, while TPS3808G33DBVR omits critical features (MR, WDI) and fixes threshold at 3.3V - making MAX6821LUK+T the only option supporting 4.63V monitoring with full feature set in SOT23-5.
Availability
MAX6821LUK+T is available at Aetrix Electronics and suitable for set-top boxes, embedded controllers, and portable/battery-powered equipment requiring stable component supply, extended temperature support (-40°C to +125°C), and RoHS-compliant packaging.
Supply support for MAX6821LUK+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 demanding industrial, automotive, and computing applications.
The MAX6821–MAX6825 family was engineered specifically for low-voltage µP supervision in space-constrained, battery-sensitive, and high-reliability embedded systems - emphasizing guaranteed reset validity at ultra-low VCC and integrated watchdog/monitoring in minimal footprint.
FAQ
What is the exact reset threshold voltage for MAX6821LUK+T?
The MAX6821LUK+T has a factory-trimmed reset threshold of 4.63V, with tolerance of ±30mV over the full -40°C to +125°C temperature range. This value is confirmed in the Electrical Characteristics table under "VCC Reset Threshold (VCC Falling)" for suffix "L", and is guaranteed by production testing - not design simulation. The MAX6821LUK+T will assert RESET when VCC falls below this threshold and hold it for ≥140ms after VCC rises above it.
Does MAX6821LUK+T include a watchdog timer and manual reset input?
Yes, the MAX6821LUK+T includes both a 1.6s nominal watchdog timer (with 1.12–2.60s range over temperature) and an active-low manual reset input (MR) with internal 50kΩ pullup. The MR pin asserts reset when pulled low and holds it for the full 140ms timeout after release. Both features are explicitly documented in the Selector Guide and Pin Description sections of the MAX6821/MAX6825 datasheet.
What package type and pin count does MAX6821LUK+T use?
The MAX6821LUK+T uses a 5-pin SOT23-5 package (outline U5-1, land pattern 21-0057), as specified in the Package Information section. Pin 1 is RESET (active-low push-pull), Pin 2 is GND, Pin 3 is MR, Pin 4 is WDI, and Pin 5 is VCC. This compact RoHS-compliant package supports reflow soldering and fits high-density PCB layouts.
Can MAX6821LUK+T operate reliably at VCC = +1.0V?
Yes, the MAX6821LUK+T guarantees correct RESET output state down to VCC = +1.0V, as stated in the General Description and confirmed in Absolute Maximum Ratings. This ensures deterministic reset behavior during deep brownout conditions where many competing supervisors lose functionality - a key differentiator validated across temperature and process corners.
What is the function of the WDI pin on MAX6821LUK+T?
The WDI (Watchdog Input) pin on MAX6821LUK+T clears the internal 1.6s watchdog timer on any rising or falling edge. If WDI remains static (high or low) beyond the timeout period, the device asserts RESET for 140ms. Leaving WDI unconnected disables the watchdog function entirely, as the internal driver cycles low-high-low every ~1.4s - a behavior explicitly documented in the Applications Information section.
MAX6821LUK+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Simple Reset/Power-On Reset
- Number of Voltages Monitored:
- 1
- Voltage - Threshold:
- 4.63V
- 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
MAX6821LUK+T FAQ
1.How can I place an order for MAX6821LUK+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6821LUK+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 MAX6821LUK+T reliable?
The price and inventory of MAX6821LUK+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6821LUK+T is usually 5 days.
3.What payment methods are accepted for MAX6821LUK+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6821LUK+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6821LUK+T?
MAX6821LUK+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6821LUK+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 MAX6821LUK+T?
For technical support, including MAX6821LUK+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6821LUK+T requirements.
6.How does Aetrix verify that MAX6821LUK+T is sourced from the original manufacturer or authorized distributors?
All MAX6821LUK+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 MAX6821LUK+T meets industry standards.
7.What is the process for return or replacement of MAX6821LUK+T?
All MAX6821LUK+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6821LUK+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 MAX6821LUK+T part is unused and in its original packaging.
Return procedure for MAX6821LUK+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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