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Analog Devices Inc./Maxim Integrated MAX6721UTZGD3-T
- Part No.:
- MAX6721UTZGD3-T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SOT-23-6
- Datasheet:
-
MAX6721UTZGD3-T.pdf
- Description:
- IC SUPERVISOR 2 CHANNEL SOT23-6
- Quantity:
- Payment:
- Shipping:
Inventory:7,500
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Product details
Overview
MAX6721UTZGD3-T from Maxim Integrated is a dual-voltage microprocessor supervisory circuit in SOT23-6 package, monitoring VCC1 (primary) and VCC2 (secondary) supplies with factory-trimmed thresholds of 4.625V and 3.075V respectively, 210ms reset timeout, watchdog timer, and open-drain active-low RST output - used to ensure reliable power-on reset and brownout protection in telecom and industrial embedded systems.
For engineers reviewing the MAX6721UTZGD3-T datasheet, MAX6721UTZGD3-T pinout, MAX6721UTZGD3-T application, or MAX6721UTZGD3-T equivalent, key selection criteria include dual-supply monitoring capability, guaranteed reset validity down to 0.8V on either supply, integrated watchdog with 35s startup/1.12s normal timeout, manual reset input with internal 50kΩ pullup, and compatibility with low-noise, battery-operated, and multivoltage system designs.
Technical Context
The MAX6721UTZGD3-T implements independent voltage comparators for VCC1 and VCC2, each with ±1.5% threshold accuracy and 20 ppm/°C tempco, asserting reset when either supply falls below its trimmed threshold. It guarantees valid reset logic state as long as VCC1 or VCC2 remains ≥0.8V, enabling operation during deep brownout conditions.
Its watchdog timer features dual-mode operation: a 35s minimum initial timeout after any reset event (power-up, MR, or watchdog-triggered), followed by a 1.12s minimum normal timeout triggered by WDI edge transitions - ensuring robust software execution monitoring without false resets during boot sequences.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC1 Threshold | 4.625V (factory-trimmed, ±1.5% tolerance; ensures precise reset assertion for 5V or 4.8V primary rails) |
| VCC2 Threshold | 3.075V (factory-trimmed, ±1.5% tolerance; matches common 3.3V secondary supply with margin) |
| Reset Timeout | 210ms (minimum; provides sufficient hold time for slow-starting processors and peripherals) |
| Watchdog Timeout | 1.12s (normal mode); 35s (startup mode); prevents premature reset during boot while catching runtime hangs |
| Supply Current | 14µA typical at 3.6V; enables use in always-on, low-power monitoring circuits without significant battery drain |
| Operating Temp | -40°C to +85°C; qualified for industrial and telecom equipment deployed in uncontrolled environments |
| Reset Output Type | Open-drain active-low RST; allows flexible level-shifting and wired-OR reset bus configurations |
Pinout & Package
MAX6721UTZGD3-T is housed in a 6-pin SOT23-6 package (2.9mm × 1.6mm × 1.1mm), surface-mount, RoHS-compliant, with thermal pad option not included. Pin 1 is marked via dot; device orientation follows JEDEC MO-178AB standard.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RST | Active-low open-drain reset output; requires external pullup; asserts when VCC1/VCC2 drop below thresholds, MR is pulled low, or watchdog times out |
| 2 | GND | Analog/digital ground reference; must be connected to system ground plane for stable comparator operation |
| 3 | MR | Active-low manual reset input; internally pulled up to VCC1 (50kΩ); debounced by 100ns glitch rejection; initiates reset on falling edge |
| 4 | VCC2 | Secondary supply input (0.9V–3.3V range); powers internal VCC2 comparator and sets RST2 reference if enabled; also used as VCC2 threshold monitor source |
| 5 | WDI | Watchdog input; edge-sensitive (rising/falling); clears watchdog timer on transition; long startup mode (35s) begins after reset, then switches to 1.12s normal mode |
| 6 | VCC1 | Primary supply input (1.8V–5.0V range); powers core logic, VCC1 comparator, and RST output driver; defines VOH for push-pull variants (not applicable here) |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent voltage monitoring | Simultaneous supervision of VCC1 (4.625V) and VCC2 (3.075V) with separate comparators and hysteresis - eliminates need for discrete supervisors or resistor networks |
| Guaranteed reset validity down to 0.8V | Ensures deterministic reset assertion even during severe brownout on either supply rail - critical for fail-safe shutdown in industrial controllers |
| Dual-mode watchdog timer | 35s startup timeout accommodates full system initialization; 1.12s normal timeout detects software lockups within sub-second response - no firmware modification needed |
| Immunity to short VCC transients | Withstands ≤20µs negative glitches at ≥100mV overdrive without spurious reset - reduces false triggers in noisy power environments |
| Low quiescent current | 14µA typical at 3.6V enables integration into battery-backed real-time clocks and always-on monitoring nodes without compromising runtime |
Applications
| Telecom Line Cards | Industrial PLC Modules |
|---|---|
Use Scenario: Monitoring 48V-to-5V DC/DC converter output (VCC1) and isolated 3.3V FPGA I/O rail (VCC2) in carrier-grade line cards. IC Role / Device Role / Timing Role: Dual-supply supervisor providing synchronized reset assertion and watchdog supervision for ARM-based control processors and SERDES PHYs. Use Value: Prevents configuration corruption during partial power loss; 210ms timeout aligns with FPGA configuration clock stability requirements. |
Use Scenario: Supervising 24V fieldbus supply (VCC1) and 3.3V microcontroller core rail (VCC2) in DIN-rail mounted programmable logic controllers. IC Role / Device Role / Timing Role: Fault-detection interface between power stage and safety-critical MCU; MR input supports emergency stop button integration. Use Value: Guaranteed reset down to 0.8V ensures safe shutdown during undervoltage faults; open-drain RST enables shared reset bus across multiple modules. |
| Network Edge Routers | Battery-Powered IoT Gateways |
Use Scenario: Validating primary 12V PoE-derived 5V rail (VCC1) and secondary 3.3V switch ASIC supply (VCC2) in compact edge routing hardware. IC Role / Device Role / Timing Role: System-level power integrity guardian; WDI tied to CPU GPIO to detect firmware hangs affecting packet forwarding. Use Value: 1.12s watchdog timeout catches stalled interrupt handlers without disrupting normal traffic flow; SOT23-6 footprint saves PCB area. |
Use Scenario: Monitoring lithium-ion battery voltage (VCC1) and regulated 3.3V sensor subsystem rail (VCC2) in solar-powered environmental gateways. IC Role / Device Role / Timing Role: Low-power supervisor enabling graceful sleep/wake transitions; MR input supports physical reset button for field recovery. Use Value: 14µA supply current extends battery life beyond 10 years in sleep mode; 210ms reset holds MCU in reset until LDO output stabilizes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-voltage supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6326UR29D3-T | Single-supply (2.93V threshold), no watchdog, no MR input, SOT23-3 package | Lacks dual-monitoring, manual reset, and watchdog - suitable only for basic single-rail reset | Select only if system uses one critical supply and requires minimal footprint/cost; cannot replace MAX6721UTZGD3-T in dual-rail designs |
| TPS3808G33DBVR | Single-supply (3.3V), includes watchdog and MR, but no secondary voltage monitor; SOT23-6 same package | Monitors only VDD - requires external circuitry to supervise second rail; higher 25µA ICC | Use when secondary supply is derived from primary and inherently tracked; verify timing compatibility with 200ms timeout vs. 210ms |
Compared with MAX6721UTZGD3-T, MAX6326UR29D3-T omits dual monitoring and fault coverage, while TPS3808G33DBVR trades VCC2 supervision for identical package size - making MAX6721UTZGD3-T uniquely suited for space-constrained, multirail industrial systems requiring coordinated reset and watchdog coverage across two independent domains.
Availability
MAX6721UTZGD3-T is available at Aetrix Electronics and suitable for telecom line cards, industrial PLC modules, network edge routers, and battery-powered IoT gateways requiring stable component supply, long-lifecycle support, and guaranteed reset behavior under brownout conditions.
Supply support for MAX6721UTZGD3-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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and computing markets.
The MAX6715–MAX6729 family was designed specifically for ultra-low-voltage, multirail microprocessor supervision in space-constrained embedded systems - emphasizing guaranteed reset validity, low ICC, and integrated watchdog functionality without external components.
FAQ
What is the exact reset threshold voltage for VCC1 and VCC2 on the MAX6721UTZGD3-T?
The MAX6721UTZGD3-T has factory-trimmed reset thresholds of 4.625V for VCC1 and 3.075V for VCC2, with ±1.5% tolerance over temperature. These values are encoded in the "ZG" suffix per Maxim's Reset Voltage Threshold Suffix Guide and are verified across -40°C to +85°C. The MAX6721UTZGD3-T does not support adjustable thresholds on these inputs - only the RSTIN pin (not present on this variant) offers external adjustment.
Does the MAX6721UTZGD3-T include a watchdog timer, and what are its timeout characteristics?
Yes, the MAX6721UTZGD3-T includes a dual-mode watchdog timer. After any reset event (power-up, MR, or watchdog timeout), it enters a 35s minimum startup mode to allow full system initialization. Upon detecting the first valid WDI edge, it switches to 1.12s minimum normal timeout mode. This behavior is inherent to the MAX6721UTZGD3-T silicon and requires no configuration - the watchdog is always active unless disabled externally by holding WDI static.
What type of reset output does the MAX6721UTZGD3-T provide, and how should it be interfaced?
The MAX6721UTZGD3-T provides an open-drain, active-low RST output (Pin 1). It requires an external pullup resistor to a valid logic rail (e.g., VCC1 or another system voltage). Typical pullup values range from 10kΩ to 100kΩ depending on bus capacitance and drive strength needs. This configuration enables wired-OR reset busing and level translation - unlike push-pull variants, the MAX6721UTZGD3-T does not drive high actively.
Can the MAX6721UTZGD3-T monitor a third supply voltage?
No, the MAX6721UTZGD3-T is a dual-supply supervisor and does not include the RSTIN input required for auxiliary voltage monitoring. That feature is present only on MAX6719/MAX6720/MAX6723–MAX6727 variants. The MAX6721UTZGD3-T monitors only VCC1 and VCC2; adding third-rail supervision would require an external comparator or selecting a different part such as MAX6723UTZGD3-T.
What is the minimum supply voltage at which the MAX6721UTZGD3-T guarantees correct reset output logic state?
The MAX6721UTZGD3-T guarantees valid reset output logic state as long as either VCC1 or VCC2 remains ≥0.8V. This specification ensures deterministic behavior during deep brownout events - for example, if VCC1 drops to 0.9V while VCC2 is at 1.2V, the device continues asserting or deasserting RST correctly. Below 0.8V on both supplies, reset behavior is not guaranteed, and external pull-down/pullup may be needed for defined states.
MAX6721UTZGD3-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SOT-23-6
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Multi-Voltage Supervisor
- Number of Voltages Monitored:
- 2
- Voltage - Threshold:
- 1.11V, 2.313V
- Output:
- Open Drain or Open Collector
- Reset:
- Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-6
MAX6721UTZGD3-T FAQ
1.How can I place an order for MAX6721UTZGD3-T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6721UTZGD3-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 MAX6721UTZGD3-T reliable?
The price and inventory of MAX6721UTZGD3-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6721UTZGD3-T is usually 5 days.
3.What payment methods are accepted for MAX6721UTZGD3-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6721UTZGD3-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6721UTZGD3-T?
MAX6721UTZGD3-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6721UTZGD3-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 MAX6721UTZGD3-T?
For technical support, including MAX6721UTZGD3-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6721UTZGD3-T requirements.
6.How does Aetrix verify that MAX6721UTZGD3-T is sourced from the original manufacturer or authorized distributors?
All MAX6721UTZGD3-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 MAX6721UTZGD3-T meets industry standards.
7.What is the process for return or replacement of MAX6721UTZGD3-T?
All MAX6721UTZGD3-T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6721UTZGD3-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 MAX6721UTZGD3-T part is unused and in its original packaging.
Return procedure for MAX6721UTZGD3-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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