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Analog Devices Inc./Maxim Integrated MAX6821VUK+T
- Part No.:
- MAX6821VUK+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-74A, SOT-753
- Datasheet:
-
MAX6821VUK+T.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:1,725
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Product details
Overview
MAX6821VUK+T from Maxim Integrated is a low-voltage microprocessor supervisory IC in 5-pin SOT23 package, featuring +1.58V reset threshold (V suffix), 140ms minimum reset timeout, 1.6s watchdog timeout, push-pull active-low RESET output, and debounced manual reset input. It monitors VCC down to +1.0V and asserts reset during power-up, brownout, or software fault conditions in embedded controllers and portable equipment.
For engineers reviewing the MAX6821VUK+T datasheet, MAX6821VUK+T pinout, MAX6821VUK+T application, or MAX6821VUK+T equivalent, this device serves as a precision voltage monitor with integrated watchdog and manual reset-critical for reliable boot sequencing and runtime fault recovery in battery-powered and industrial µP systems.
Technical Context
The MAX6821VUK+T implements a precision bandgap-based voltage reference to detect VCC falling below 1.58V ±1.5% over –40°C to +125°C, with 60ppm/°C temperature coefficient and 2×VTH hysteresis. Its internal reset generator holds RESET asserted for ≥140ms after VCC recovers above threshold.
A dedicated watchdog timer monitors WDI transitions with 1.6s nominal timeout (±40% over temperature); it clears on any rising/falling edge and remains disabled if WDI is left floating or three-stated. MR input includes 50kΩ internal pullup and rejects <100ns glitches.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 1.58V ±1.5% - precisely triggers reset when VCC drops below nominal supply for +1.8V systems |
| Reset Timeout Period | 140ms (min) - ensures µP remains held in reset long enough for stable power rail recovery |
| Watchdog Timeout | 1.6s (nominal) - provides sufficient margin to detect firmware hangs without false triggers |
| Operating Voltage Range | +1.2V to +5.5V - supports operation down to 1.2V while guaranteeing valid reset assertion to +1.0V |
| Supply Current | 20µA (max at +125°C, VCC = +3.6V) - enables ultra-low-power operation in battery-backed systems |
| RESET Output Type | Push-pull active-low - drives low directly 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 |
Pinout & Package
Package: 5-pin SOT23-5 (U5-1 outline), footprint-compatible with industry-standard 5-lead SOT-23, 1.6mm × 2.9mm body size, 0.95mm height.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RESET | Active-low push-pull reset output - asserts low during VCC brownout, MR activation, or watchdog timeout; drives µP reset pin directly |
| 2 | GND | Ground reference - common return path for all internal circuits and reset output sink current |
| 3 | MR | Manual reset input - logic-low pulse ≥1µs forces reset; internal 50kΩ pullup allows NC or VCC tie-off |
| 4 | WDI | Watchdog input - toggling within 1.6s prevents reset; left floating disables watchdog function |
| 5 | VCC | Supply and monitoring input - powers device and serves as monitored rail; reset asserts when VCC falls below 1.58V |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed reset validity to VCC = +1.0V | Ensures reliable reset assertion even during deep brownout or battery sag below operating range |
| No external components required | Integrates voltage reference, timer, pullup, and driver - reduces BOM count and PCB area vs discrete solutions |
| Immunity to short negative VCC transients | Withstands ≤20µs, 100mV VCC glitches without spurious reset - improves noise resilience in noisy environments |
| Debounced manual reset input | Internal filtering rejects <100ns noise pulses - eliminates need for external RC debounce network |
| 1.6s watchdog timeout with edge-triggered clear | Prevents firmware lockup by requiring periodic WDI toggles - avoids stuck-loop failure modes |
Applications
| Set-Top Boxes | Portable/Battery-Powered Equipment |
|---|---|
Use Scenario: Power sequencing and fault recovery during HDMI hot-plug events or firmware updates. IC Role / Device Role / Timing Role: Supervisory IC asserting active-low reset to ARM-based SoC during VCC droop or watchdog timeout. Use Value: Prevents corrupted boot states and ensures deterministic recovery after transient power faults. | Use Scenario: Maintaining system integrity in handheld medical meters with single-cell Li-ion supply. IC Role / Device Role / Timing Role: Monitors 1.8V LDO output; asserts reset before battery voltage collapses below µP operational floor. Use Value: Extends usable battery life by enabling safe shutdown at 1.58V threshold instead of arbitrary cutoff. |
| Embedded Controllers | Critical µP Monitoring |
Use Scenario: Industrial PLC I/O module requiring fail-safe restart after ESD-induced code corruption. IC Role / Device Role / Timing Role: Dual-role supervisor providing both power-on reset and runtime watchdog supervision of Cortex-M4 firmware. Use Value: Eliminates need for separate reset IC and external watchdog timer, reducing component count and layout complexity. | Use Scenario: Data acquisition system where missed sensor readings must trigger immediate µP reset. IC Role / Device Role / Timing Role: Precision voltage monitor with 60ppm/°C drift control and 140ms timeout ensuring consistent reset timing across temperature. Use Value: Guarantees repeatable reset behavior from –40°C to +125°C without calibration or compensation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6822VUK+T | Open-drain RESET output instead of push-pull; identical threshold, timeout, and watchdog specs | Required when interfacing with µPs having bidirectional reset pins (e.g., legacy 68HC11) needing external pullup | Select MAX6822VUK+T only if open-drain drive and external pullup are explicitly needed for bus-sharing reset lines. |
| TPS3808G15DBVR | 1.55V fixed threshold, 200ms reset timeout, no manual reset input, same SOT23-5 package | Lacks MR and watchdog - suitable only for basic power-monitoring applications without runtime supervision | Choose TPS3808G15DBVR only when manual reset and watchdog functions are unnecessary and longer reset timeout is acceptable. |
Compared with MAX6822VUK+T, the MAX6821VUK+T offers direct-drive reset capability eliminating external components; versus TPS3808G15DBVR, it adds critical runtime fault detection via watchdog and operator-initiated reset-making it essential for safety-critical or field-upgradable embedded systems.
Availability
MAX6821VUK+T is available at Aetrix Electronics and suitable for set-top boxes, portable/battery-powered equipment, and embedded controllers requiring stable component supply with guaranteed long-term availability.
Supply support for MAX6821VUK+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 is a semiconductor company specializing in analog and mixed-signal ICs for power, sensing, interface, and reliability-critical applications.
The MAX6821–MAX6825 family was designed specifically for low-voltage microprocessor supervision in space-constrained, battery-sensitive, and thermally demanding environments-emphasizing precision threshold accuracy, ultra-low quiescent current, and integrated fault-detection features.
FAQ
What is the exact reset threshold voltage of the MAX6821VUK+T?
The MAX6821VUK+T has a factory-trimmed reset threshold of 1.58V, specified with ±1.5% tolerance over –40°C to +125°C and 60ppm/°C temperature coefficient. This value is confirmed in the Threshold Suffix Guide where "V" denotes 1.58V, and electrical characteristics tables list VTH = 1.52V (min) to 1.62V (max) at full temperature range. The MAX6821VUK+T uses this precise threshold to supervise +1.8V rails reliably.
Does the MAX6821VUK+T include a watchdog timer and manual reset functionality?
Yes, the MAX6821VUK+T integrates both a 1.6s watchdog timer and an active-low manual reset (MR) input with internal 50kΩ pullup. The watchdog monitors WDI transitions and triggers reset if no edge occurs within timeout; MR asserts reset when pulled low for ≥1µs. These functions are explicitly confirmed in the Selector Guide and Pin Description sections of the MAX6821VUK+T datasheet.
What is the RESET output configuration of the MAX6821VUK+T?
The MAX6821VUK+T features a push-pull active-low RESET output, meaning it actively drives low during reset assertion and high-impedance (not actively driven high) when inactive. This differs from open-drain variants like MAX6822 and eliminates the need for an external pullup resistor. The output is guaranteed functional down to VCC = +1.0V, as verified in the Absolute Maximum Ratings and Electrical Characteristics tables for MAX6821VUK+T.
Can the MAX6821VUK+T operate with supply voltages below 1.8V?
Yes, the MAX6821VUK+T operates with VCC as low as +1.2V over its full temperature range (–40°C to +125°C), and its RESET output remains valid down to +1.0V. This enables use in ultra-low-voltage systems such as single-cell Li-ion or NiMH-powered devices. The 1.58V threshold is optimized for +1.8V supplies but functions correctly across the entire 1.2V–5.5V operating range specified for MAX6821VUK+T.
Is the MAX6821VUK+T RoHS-compliant and what package does it use?
Yes, the MAX6821VUK+T is RoHS-compliant, indicated by the "+T" suffix per Maxim's ordering nomenclature. It uses a 5-pin SOT23-5 package (outline U5-1), measuring 1.6mm × 2.9mm with 0.95mm height. This package is documented in the Package Information section and matches land pattern 21-0057, confirming mechanical compatibility with standard SOT-23 footprints used for MAX6821VUK+T.
MAX6821VUK+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:
- 1.58V
- 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
MAX6821VUK+T FAQ
1.How can I place an order for MAX6821VUK+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6821VUK+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 MAX6821VUK+T reliable?
The price and inventory of MAX6821VUK+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6821VUK+T is usually 5 days.
3.What payment methods are accepted for MAX6821VUK+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6821VUK+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6821VUK+T?
MAX6821VUK+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6821VUK+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 MAX6821VUK+T?
For technical support, including MAX6821VUK+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6821VUK+T requirements.
6.How does Aetrix verify that MAX6821VUK+T is sourced from the original manufacturer or authorized distributors?
All MAX6821VUK+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 MAX6821VUK+T meets industry standards.
7.What is the process for return or replacement of MAX6821VUK+T?
All MAX6821VUK+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6821VUK+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 MAX6821VUK+T part is unused and in its original packaging.
Return procedure for MAX6821VUK+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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