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Analog Devices Inc./Maxim Integrated MAX6721UTVDD3+
- Part No.:
- MAX6721UTVDD3+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- -
- Datasheet:
-
MAX6721UTVDD3+.pdf
- Description:
- MAX6721UTVDD3+
- Quantity:
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Product details
Overview
MAX6721UTVDD3+ from Maxim Integrated is a dual-voltage microprocessor supervisory circuit in 6-pin SOT23 package, monitoring VCC1 (4.625V threshold) and VCC2 (3.075V threshold) with 210ms minimum reset timeout, watchdog timer (35s startup / 1.12s normal), and open-drain active-low RST output. It ensures reliable system reset during power-up, brownout, or software fault in battery-powered telecom and industrial controllers.
For engineers reviewing the MAX6721UTVDD3+ datasheet, MAX6721UTVDD3+ pinout, MAX6721UTVDD3+ application, or MAX6721UTVDD3+ equivalent, key selection factors include guaranteed reset validity down to VCC1/VCC2 = 0.8V, 14µA typical supply current at 3.6V, immunity to short VCC transients, and support for manual reset and watchdog supervision without external components.
Technical Context
The MAX6721UTVDD3+ integrates dual independent voltage comparators with factory-trimmed thresholds (VTH1 = 4.625V, VTH2 = 3.075V), a dual-mode watchdog timer (35s min startup period, 1.12s min normal timeout), and an open-drain active-low reset output referenced to VCC1. It asserts reset when either supply falls below its threshold or when the watchdog times out.
It features a manual reset input (MR) with internal 50kΩ pullup to VCC1, guarantees valid reset logic state with VCC1 or VCC2 ≥ 0.8V, and includes 20ppm/°C reset threshold tempco and 0.5% hysteresis referenced to typical VTH. The device operates across –40°C to +85°C and draws only 14µA typical supply current at 3.6V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC1 Reset Threshold | 4.625V (factory-trimmed, ±125mV tolerance); ensures precise power-on reset for 5V or 4.8V primary rails |
| VCC2 Reset Threshold | 3.075V (factory-trimmed, ±75mV tolerance); monitors 3.3V secondary supply with tight margin |
| Reset Timeout Period | 210ms (minimum); provides sufficient hold time for µP initialization after power stabilization |
| Watchdog Timeout | 1.12s (normal mode), 35s (startup mode); enables safe boot sequence and rapid fault detection |
| Supply Current | 14µA (typical at 3.6V); enables ultra-low-power operation in battery-backed systems |
| Operating Temperature | –40°C to +85°C; qualified for industrial and telecom equipment environments |
| Reset Output Type | Open-drain active-low RST; allows flexible level-shifting and wired-OR reset bus implementation |
Pinout & Package
MAX6721UTVDD3+ is housed in a 6-pin SOT23-6 package (2.9mm × 1.6mm × 1.1mm), surface-mount, RoHS-compliant lead-free variant (indicated by '+' suffix).
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RST | Active-low open-drain reset output; asserted low during VCC1/VCC2 undervoltage or watchdog timeout; requires external pullup |
| 2 | GND | Ground reference for all internal circuitry and comparator inputs |
| 3 | MR | Active-low manual reset input; internally pulled up to VCC1 (50kΩ); initiates reset on logic-low pulse ≥1µs |
| 4 | VCC2 | Secondary supply input (0.9V–3.3V range); powers internal circuitry when > VCC1 and sets VTH2 monitor reference |
| 5 | VCC1 | Primary supply input (1.8V–5.0V range); powers device when > VCC2 and sets VTH1 monitor reference |
| 6 | WDI | Watchdog input; rising/falling edge clears timer; timeout occurs if static high/low exceeds 1.12s (normal) or 35s (startup) |
Key Features
| Feature | Design Value |
|---|---|
| Dual-voltage monitoring with factory-trimmed thresholds | Eliminates external resistor dividers for VCC1=4.625V and VCC2=3.075V, reducing BOM count and layout area |
| Dual-mode watchdog timer | 35s startup window prevents false reset during boot; 1.12s normal timeout ensures rapid software hang detection |
| Guaranteed reset validity down to 0.8V supply | Ensures deterministic reset assertion even during deep brownout conditions common in battery discharge profiles |
| Immunity to short VCC transients | Rejects glitches <20µs (at 100mV overdrive), avoiding spurious resets in noisy power environments |
| Ultra-low quiescent current | 14µA typical at 3.6V enables multi-year operation in coin-cell–powered IoT sensors and backup systems |
Applications
| Telecom Line Card Power Management | Industrial PLC I/O Module |
|---|---|
|
Use Scenario: Monitors 48V-to-5V DC/DC primary rail and isolated 3.3V logic rail in carrier-grade line cards. IC Role / Device Role / Timing Role: Dual-supply supervisor asserting reset during input undervoltage or converter failure; watchdog guards against firmware lockup. Use Value: Prevents corrupted register states and communication loss during partial power faults, meeting GR-1089 EMC and NEBS Level 3 requirements. |
Use Scenario: Ensures clean boot and runtime supervision of ARM Cortex-M7 core and isolated CAN/RS-485 PHY supplies in modular PLC backplanes. IC Role / Device Role / Timing Role: Primary supervisor for 5V CPU rail and 3.3V peripheral rail; MR supports field-service reset; WDI tracks main loop execution. Use Value: Enables deterministic recovery from brownout-induced flash corruption and eliminates need for external RC reset networks. |
| Portable Medical Monitor Battery Backup | Set-Top Box SoC Power Sequencing |
|
Use Scenario: Supervises main Li-ion 3.7V rail and backup supercapacitor 2.5V rail in ECG/SpO₂ devices with cold-temperature operation. IC Role / Device Role / Timing Role: Dual-threshold monitor with 0.8V validity guarantee ensures reset remains active until both rails stabilize post-battery swap. Use Value: Meets IEC 62304 Class C safety requirements by preventing undefined MCU behavior during battery transition events. |
Use Scenario: Controls power-on reset timing for quad-core SoC (VDDIO=1.8V, VDDA=1.2V, VDDCPU=0.9V) and DDR3 memory in consumer STB platforms. IC Role / Device Role / Timing Role: Configured as dual-supply supervisor for 1.8V I/O and 1.2V analog rails; 210ms timeout aligns with SoC POR specification. Use Value: Replaces discrete reset IC + RC network, reducing footprint by 65% and eliminating temperature drift in reset delay. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-voltage supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS3808G33DBVR | Single-supply monitor (3.3V only), no watchdog, push-pull RST, 200ms timeout | Lacks VCC2 monitoring and WDI; suitable only for single-rail systems | Select when only 3.3V rail supervision is needed and watchdog is handled externally |
| ADM6705ARJZ-REEL7 | Dual-supply (2.5V/3.3V thresholds), no watchdog, open-drain RST, 200ms timeout, -40°C to +125°C | Higher temperature rating but no WDI; fixed thresholds not matching MAX6721UTVDD3+'s 4.625V/3.075V pair | Choose for extended-temp industrial use where watchdog is unnecessary and 4.625V threshold is not required |
Compared with TPS3808G33DBVR and ADM6705ARJZ-REEL7, the MAX6721UTVDD3+ uniquely combines dual-rail monitoring at 4.625V/3.075V, integrated dual-mode watchdog, and guaranteed 0.8V operation-making it optimal for telecom and industrial systems requiring coordinated reset and runtime fault coverage.
Availability
MAX6721UTVDD3+ is available at Aetrix Electronics and suitable for telecom line cards, industrial PLC modules, portable medical monitors, and set-top box SoC power sequencing requiring stable component supply and long-term lifecycle support.
Supply support for MAX6721UTVDD3+ 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, mixed-signal, and power management ICs for demanding industrial, automotive, and communications applications.
The MAX6715–MAX6729 family delivers ultra-low-voltage dual/triple supervisory circuits optimized for multivoltage embedded systems where space, power, and reliability are critical-enabling compact, robust reset architectures without external passive components.
FAQ
What is the exact reset threshold voltage for VCC1 and VCC2 on the MAX6721UTVDD3+?
The MAX6721UTVDD3+ has factory-trimmed reset thresholds of 4.625V for VCC1 (±125mV) and 3.075V for VCC2 (±75mV), as defined by the 'TD' suffix per Maxim's Reset Voltage Threshold Suffix Guide. These values are measured under standard conditions (TA = +25°C) and remain stable across –40°C to +85°C with 20ppm/°C tempco.
Does the MAX6721UTVDD3+ support watchdog functionality, and what are its timing modes?
Yes, the MAX6721UTVDD3+ includes a dual-mode watchdog timer: a 35s minimum startup period (to accommodate full system boot) followed by a 1.12s minimum normal timeout period (for rapid software fault detection). The watchdog is triggered by static WDI state and cleared by any WDI edge, ensuring robust supervision of µP execution flow.
What package type and pin count does the MAX6721UTVDD3+ use?
The MAX6721UTVDD3+ uses a 6-pin SOT23-6 package (2.9mm × 1.6mm × 1.1mm), RoHS-compliant and lead-free (indicated by the '+' suffix). Pinout includes VCC1, VCC2, GND, RST (open-drain), MR, and WDI - fully documented in Maxim's MAX6715–MAX6729 datasheet revision 5.
Can the MAX6721UTVDD3+ operate reliably during deep brownout conditions?
Yes, the MAX6721UTVDD3+ guarantees valid reset output logic state with either VCC1 or VCC2 ≥ 0.8V - enabling deterministic reset assertion even during severe brownout events common in battery-powered systems. This is confirmed in Absolute Maximum Ratings and Electrical Characteristics tables.
Is an external pullup resistor required for the RST output of the MAX6721UTVDD3+?
Yes, the MAX6721UTVDD3+ features an open-drain RST output, requiring an external pullup resistor to VCC1 (or another appropriate rail) to establish a defined HIGH state when reset is deasserted. Typical values range from 10kΩ to 100kΩ depending on bus capacitance and rise-time requirements.
MAX6721UTVDD3+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- -
- Number of Voltages Monitored:
- -
- Voltage - Threshold:
- -
- Output:
- -
- Reset:
- -
- Reset Timeout:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
MAX6721UTVDD3+ FAQ
1.How can I place an order for MAX6721UTVDD3+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6721UTVDD3+ 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 MAX6721UTVDD3+ reliable?
The price and inventory of MAX6721UTVDD3+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6721UTVDD3+ is usually 5 days.
3.What payment methods are accepted for MAX6721UTVDD3+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6721UTVDD3+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6721UTVDD3+?
MAX6721UTVDD3+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6721UTVDD3+ 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 MAX6721UTVDD3+?
For technical support, including MAX6721UTVDD3+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6721UTVDD3+ requirements.
6.How does Aetrix verify that MAX6721UTVDD3+ is sourced from the original manufacturer or authorized distributors?
All MAX6721UTVDD3+ 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 MAX6721UTVDD3+ meets industry standards.
7.What is the process for return or replacement of MAX6721UTVDD3+?
All MAX6721UTVDD3+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX6721UTVDD3+, 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 MAX6721UTVDD3+ part is unused and in its original packaging.
Return procedure for MAX6721UTVDD3+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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