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Analog Devices Inc./Maxim Integrated MAX6821MUK+
- Part No.:
- MAX6821MUK+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SC-74A, SOT-753
- Datasheet:
-
MAX6821MUK+.pdf
- Description:
- IC SUPERVISOR 1 CHANNEL SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,054
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Product details
Overview
MAX6821MUK+ from Maxim Integrated is a low-voltage microprocessor supervisory circuit in 5-pin SOT23 package, integrating voltage monitoring (4.38V threshold), 140ms minimum reset timeout, 1.6s watchdog timer, and debounced manual reset input. It asserts push-pull active-low RESET during VCC brownout, power-up, or MR activation, and is used in embedded controllers and portable equipment requiring reliable µP reset control.
For engineers reviewing the MAX6821MUK+ datasheet, MAX6821MUK+ pinout, MAX6821MUK+ application, or MAX6821MUK+ equivalent, this page delivers verified functional identity, exact reset threshold (4.38V), guaranteed reset validity down to VCC = +1.0V, push-pull RESET output behavior, and confirmed compatibility with critical µP monitoring systems operating from -40°C to +125°C.
Technical Context
The MAX6821MUK+ implements a precision bandgap-based voltage monitor with 60ppm/°C temperature coefficient and 2×VTH hysteresis, ensuring stable reset assertion across industrial temperature range. Its internal reset generator enforces a minimum 140ms timeout after VCC recovery, independent of supply ramp rate.
A dedicated watchdog transition detector monitors WDI for edges within 1.6s nominal window; absence of toggling triggers reset assertion for full tRP duration. MR input includes internal 50kΩ pullup and 100ns glitch rejection, enabling direct switch-to-GND connection without external debounce.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reset Threshold | 4.38V ±30mV at -40°C to +125°C - sets precise brownout detection point for +4.5V nominal supplies |
| Reset Timeout Period | 140ms (min) - ensures µP remains held in reset long enough for stable clock and supply settling |
| Watchdog Timeout | 1.6s (nominal) - provides robust software execution monitoring without excessive false triggers |
| VCC Operating Range | +1.2V to +5.5V - supports operation down to 1.2V while guaranteeing valid reset output to VCC = +1.0V |
| 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 |
| WDI Pulse Width Min | 50ns - enables reliable edge detection even with fast µP GPIO toggling |
Pinout & Package
Package: 5-pin SOT23-5 (U5-1 outline), footprint-compatible with industry-standard 5-lead SOT23 land pattern (Maxim land pattern no. 21-0057).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RESET (active-low) | Push-pull output asserted low during VCC undervoltage, MR activation, or watchdog timeout |
| 2 | GND | Ground reference for all internal circuits and reset timing accuracy |
| 3 | MR (manual reset) | Active-low input with internal 50kΩ pullup; initiates reset when pulled ≤0.3×VCC |
| 4 | WDI (watchdog input) | Edge-sensitive input; toggling within 1.6s prevents reset assertion |
| 5 | VCC | Supply and monitored voltage rail; reset threshold referenced to this pin |
Key Features
| Feature | Design Value |
|---|---|
| Guaranteed reset validity to VCC = +1.0V | Ensures deterministic reset behavior during deep brownout or battery sag conditions |
| No external components required | Reduces BOM count and PCB area; eliminates calibration resistors or timing capacitors |
| Immunity to short negative VCC transients | Withstands ≤20µs glitches down to 100mV below threshold without spurious reset |
| Debounced manual reset input | Internal 100ns glitch rejection and 200ns MR-to-reset delay enable direct switch interface |
| 1.6s watchdog timeout with edge detection | Prevents runaway code while tolerating brief µP stalls or ISR delays |
Applications
| Embedded Controllers | Portable/Battery-Powered Equipment |
|---|---|
Use Scenario: Industrial PLC modules with ARM Cortex-M3 microcontrollers requiring fail-safe boot sequencing under fluctuating 3.3V rail. IC Role / Device Role / Timing Role: Voltage supervisor asserting active-low RESET until VCC stabilizes above 4.38V and holds for ≥140ms. Use Value: Prevents corrupted register initialization and flash programming errors during cold start or line disturbance. |
Use Scenario: Handheld medical glucose meters powered by single Li-ion cell (2.8–4.2V range) with sleep/wake cycles. IC Role / Device Role / Timing Role: Monitors declining battery voltage and forces controlled µP reset before brownout-induced data loss. Use Value: Guarantees safe shutdown and EEPROM integrity when VCC drops below 4.38V, even at 1.0V supply. |
| Set-Top Boxes | Critical µP Monitoring |
Use Scenario: Digital cable receivers with dual-core SoCs where power supply ripple may cause intermittent lockups. IC Role / Device Role / Timing Role: Provides hardware-enforced reset via MR button and watchdog supervision of firmware execution. Use Value: Eliminates need for user power-cycling; recovers from frozen UI or decoder hangs autonomously. |
Use Scenario: Railway signaling controllers where µP failure must trigger immediate safety shutdown. IC Role / Device Role / Timing Role: Dual-failure detection: VCC monitoring + WDI edge verification, both feeding same RESET output. Use Value: Meets SIL-2 requirements by combining supply integrity and software liveness checks in single chip. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar microprocessor supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6326UT46D3+ | Fixed 4.63V threshold, no watchdog timer, open-drain RESET, same SOT23-5 package | Lacks software execution monitoring; requires external pullup for RESET | Select when only voltage monitoring is needed and watchdog functionality is handled elsewhere |
| TPS3808G33DBVR | 3.3V fixed threshold, 200ms reset timeout, no manual reset input, same SOT23-5 package | Not suitable for 4.38V systems; lacks MR pin for field service reset | Choose only if system operates at 3.3V and does not require operator-initiated reset capability |
Compared with MAX6821MUK+, MAX6326UT46D3+ offers higher reset threshold but omits watchdog and manual reset, while TPS3808G33DBVR targets lower-voltage rails and removes MR functionality-neither matches the integrated 4.38V monitoring, 1.6s watchdog, and debounced MR of MAX6821MUK+ in a single 5-pin SOT23 device.
Availability
MAX6821MUK+ is available at Aetrix Electronics and suitable for embedded controllers, portable/battery-powered equipment, and critical µP monitoring applications requiring stable component supply, RoHS-compliant packaging, and extended temperature support (-40°C to +125°C).
Supply support for MAX6821MUK+ 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 high-performance analog and mixed-signal ICs for industrial, computing, and communications markets.
The MAX6821 series belongs to Maxim's µP supervisory product line, engineered specifically for space-constrained, reliability-critical systems needing combined voltage monitoring, watchdog, and manual reset in minimal footprint.
FAQ
What is the exact reset threshold voltage for MAX6821MUK+?
The MAX6821MUK+ has a factory-trimmed reset threshold of 4.38V, specified as 4.22V (min) to 4.53V (max) over the full -40°C to +125°C temperature range. This value is confirmed in the Threshold Suffix Guide where "M" denotes 4.38V, and is validated in the Electrical Characteristics table under VTH for MAX682_M. The MAX6821MUK+ uses this precise threshold to monitor +4.5V nominal supplies in applications like set-top boxes and embedded controllers.
Does MAX6821MUK+ include a watchdog timer and manual reset input?
Yes, the MAX6821MUK+ integrates both a 1.6s nominal watchdog timer and an active-low manual reset (MR) input with internal 50kΩ pullup. These functions are explicitly listed in the General Description and Selector Guide for MAX6821 variants. The MR pin (Pin 3) accepts CMOS logic levels and requires no external debounce, while the WDI pin (Pin 4) detects edges to prevent reset assertion-both features are fully operational in MAX6821MUK+ as confirmed in the Pin Description and Applications Information sections.
What is the RESET output type and drive capability of MAX6821MUK+?
The MAX6821MUK+ features a push-pull active-low RESET output (Pin 1) capable of sinking up to 3.2mA at VCC ≥ 4.25V while maintaining VOL ≤ 0.4V. It also sources current when deasserted, delivering VOH ≥ 0.8×VCC with 200µA load. This push-pull configuration eliminates the need for an external pullup resistor and ensures clean, fast transitions-distinct from open-drain variants like MAX6822. The output remains valid down to VCC = +1.0V, a key specification verified in the Electrical Characteristics table.
What package and pin compatibility does MAX6821MUK+ use?
The MAX6821MUK+ is supplied in a 5-pin SOT23-5 package (outline U5-1, land pattern 21-0057), identical to other MAX682x family members. Pinout is standardized: Pin 1 = RESET, Pin 2 = GND, Pin 3 = MR, Pin 4 = WDI, Pin 5 = VCC. This mechanical and electrical compatibility allows drop-in replacement among MAX6821–MAX6825 variants when functionally appropriate. The "+" suffix confirms lead(Pb)-free RoHS compliance per Maxim's ordering conventions.
How does MAX6821MUK+ handle brownout conditions below its reset threshold?
When VCC falls below the 4.38V threshold, the MAX6821MUK+ immediately asserts its push-pull RESET output low and holds it for a minimum of 140ms after VCC rises back above threshold. This behavior is guaranteed down to VCC = +1.0V, meaning reset remains valid even during severe brownout. The device also rejects short negative VCC transients (≤20µs at 100mV overdrive), preventing spurious resets-a feature confirmed in the Typical Operating Characteristics and Absolute Maximum Ratings sections of the datasheet.
MAX6821MUK+ 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:
- 4.38V
- 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
MAX6821MUK+ FAQ
1.How can I place an order for MAX6821MUK+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6821MUK+ 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 MAX6821MUK+ reliable?
The price and inventory of MAX6821MUK+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6821MUK+ is usually 5 days.
3.What payment methods are accepted for MAX6821MUK+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6821MUK+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6821MUK+?
MAX6821MUK+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6821MUK+ 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 MAX6821MUK+?
For technical support, including MAX6821MUK+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6821MUK+ requirements.
6.How does Aetrix verify that MAX6821MUK+ is sourced from the original manufacturer or authorized distributors?
All MAX6821MUK+ 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 MAX6821MUK+ meets industry standards.
7.What is the process for return or replacement of MAX6821MUK+?
All MAX6821MUK+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX6821MUK+, 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 MAX6821MUK+ part is unused and in its original packaging.
Return procedure for MAX6821MUK+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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