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Analog Devices Inc./Maxim Integrated MAX6721UTSYD3+
- Part No.:
- MAX6721UTSYD3+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- -
- Datasheet:
-
MAX6721UTSYD3+.pdf
- Description:
- MAX6721UTSYD3+
- Quantity:
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Product details
Overview
MAX6721UTSYD3+ from Maxim Integrated is a dual-voltage microprocessor supervisory circuit in SOT23-6 package, monitoring VCC1 (4.625V threshold) and VCC2 (3.075V threshold) with 210ms 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 embedded controllers.
For engineers reviewing the MAX6721UTSYD3+ datasheet, MAX6721UTSYD3+ pinout, MAX6721UTSYD3+ application, or MAX6721UTSYD3+ equivalent, key selection criteria include dual-supply monitoring range (1.8–5.0V / 0.9–3.3V), guaranteed reset validity down to VCC = 0.8V, low 14µA supply current, and integrated watchdog with long startup period for complex boot sequences.
Technical Context
The MAX6721UTSYD3+ implements independent voltage comparators for VCC1 and VCC2, each with factory-trimmed thresholds (4.625V ±125mV and 3.075V ±75mV), hysteresis of 0.5%, and tempco of 20ppm/°C. Reset assertion occurs on first fault detection and remains active for 210ms minimum after all monitored supplies exceed thresholds.
Its watchdog timer operates in dual-mode: 35s minimum initial timeout after any reset event (power-on, MR, or watchdog-triggered), then transitions to 1.12s minimum normal timeout upon first WDI edge detection. The RST output is open-drain, requiring external pullup, and remains valid while either VCC1 or VCC2 ≥ 0.8V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC1 Threshold | 4.625V (±125mV) - sets primary supply brownout detection point for 5V rail systems |
| VCC2 Threshold | 3.075V (±75mV) - enables reliable monitoring of 3.3V I/O or auxiliary rails |
| Reset Timeout | 210ms (min) - ensures µP completes power-on initialization before release |
| Watchdog Timeout | 35s (min startup), 1.12s (min normal) - accommodates lengthy boot firmware before enforcing runtime supervision |
| Supply Current | 14µA (typ at 3.6V) - supports multi-year operation in coin-cell–powered IoT nodes |
| Operating Temp | -40°C to +85°C - qualified for industrial and telecom equipment environments |
| Reset Propagation | 20µs max VCC-to-RST delay - provides fast fault response without false triggering on transients |
Pinout & Package
SOT23-6 package: 2.9mm × 1.6mm × 1.1mm body, gull-wing leads, RoHS-compliant lead-free finish (+ suffix).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RST | Active-low open-drain reset output; requires external pullup; asserts when VCC1/VCC2 drop below thresholds or WDI timeout occurs |
| 2 | GND | Analog/digital ground reference; must be low-impedance connection to system ground plane |
| 3 | MR | Active-low manual reset input; internal 50kΩ pullup to VCC1; 1µs minimum pulse width required for reliable assertion |
| 4 | VCC2 | Secondary supply input (0.9–3.3V); powers internal comparator for VCC2 monitoring and sets RST2 reference if present |
| 5 | VCC1 | Primary supply input (1.8–5.0V); powers device core and sets RST output reference voltage |
| 6 | WDI | Watchdog input; rising/falling edge clears timer; held high/low >1.12s triggers reset after initial 35s window |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent voltage monitoring | Simultaneous VCC1 (4.625V) and VCC2 (3.075V) supervision with separate comparators avoids single-point failure in multirail systems |
| Guaranteed reset validity down to 0.8V | Ensures deterministic reset state even during deep brownout conditions where VCC drops near device cutoff |
| Dual-mode watchdog timer | 35s startup timeout prevents spurious resets during boot; 1.12s runtime timeout catches stalled firmware execution |
| Immunity to short VCC transients | Withstands ≤20µs negative glitches up to 100mV below threshold without asserting reset, reducing false triggers |
| Low 14µA supply current | Enables integration into always-on subsystems without compromising battery life in portable equipment |
Applications
| Telecom Line Card Power Monitoring | Industrial PLC CPU Module |
|---|---|
Use Scenario: Monitors +5V primary and +3.3V I/O rails on a carrier-grade line card with hot-swap capability. IC Role / Device Role / Timing Role: Dual-supply supervisor asserting open-drain RST to ARM Cortex-A9 processor and FPGA configuration logic. Use Value: Prevents partial initialization by holding reset until both rails stabilize above 4.625V and 3.075V for ≥210ms, ensuring deterministic boot. | Use Scenario: Embedded controller in programmable logic controller with isolated 24V DC input converted to 5V/3.3V rails. IC Role / Device Role / Timing Role: Fault detector providing reset signal and watchdog supervision for real-time control firmware. Use Value: 35s initial watchdog window allows full FPGA configuration and RTOS startup; 1.12s runtime timeout detects task lockups in cyclic executive. |
| Portable Medical Monitor | Set-Top Box Mainboard |
Use Scenario: Battery-powered ECG monitor using Li-ion cell (3.0–4.2V) stepped down to 3.3V and 1.8V rails. IC Role / Device Role / Timing Role: Low-power supervisor monitoring VCC1 (3.3V) and VCC2 (1.8V) with manual reset button interface. Use Value: 14µA quiescent current extends battery life; MR input enables field technician-initiated recalibration reset without power cycle. | Use Scenario: Consumer STB mainboard with 12V input converted to 5V, 3.3V, and 1.2V rails for SoC, memory, and peripherals. IC Role / Device Role / Timing Role: System integrity guardian detecting undervoltage on 3.3V I/O rail and 1.2V core rail via resistor divider on RSTIN (not used here). Use Value: Open-drain RST interfaces directly to bidirectional reset pin of Broadcom BCM7xxx SoC; 210ms timeout aligns with DDR3 initialization sequence. |
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+ | Single-supply (2.93V threshold), no watchdog, 200ms timeout, SOT23-5 | Lacks VCC2 monitoring and WDI; suitable only for single-rail systems | Select when only primary rail supervision is needed and board space is constrained to 5-pin footprint |
| TPS3808G33DBVR | Single-supply (3.3V threshold), no watchdog, 200ms timeout, SOT23-6, 1.6µA ICC | No dual-monitoring or watchdog; lower supply current but no fault coverage for secondary rail | Prefer for ultra-low-power single-rail applications where secondary rail reliability is managed elsewhere |
Compared with MAX6721UTSYD3+, MAX6326UR29D3+ reduces functionality (no VCC2 or WDI) but saves board area; TPS3808G33DBVR offers lower ICC but cannot supervise two rails simultaneously-making MAX6721UTSYD3+ essential for systems requiring coordinated dual-rail reset and runtime watchdog enforcement.
Availability
MAX6721UTSYD3+ is available at Aetrix Electronics and suitable for telecom line cards, industrial PLCs, portable medical monitors, and set-top box mainboards requiring stable component supply with guaranteed long-term availability.
Supply support for MAX6721UTSYD3+ 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 industrial, automotive, communications, and computing markets.
The MAX6715–MAX6729 family delivers ultra-low-voltage dual/triple supervisory circuits targeting space-constrained, multirail embedded systems where guaranteed reset validity down to 0.8V and integrated watchdog supervision are critical.
FAQ
What are the exact reset threshold voltages for MAX6721UTSYD3+?
The MAX6721UTSYD3+ has factory-trimmed reset thresholds of 4.625V (±125mV) for VCC1 and 3.075V (±75mV) for VCC2, as indicated by the 'SY' suffix per Maxim's Reset Voltage Threshold Suffix Guide. These values are tested and guaranteed over -40°C to +85°C and enable precise brownout detection for 5V and 3.3V rails. The MAX6721UTSYD3+ does not support adjustable RSTIN or PFI inputs.
Does MAX6721UTSYD3+ include a watchdog timer, and how is it configured?
Yes, MAX6721UTSYD3+ integrates a dual-mode watchdog timer with a 35s minimum initial timeout after any reset event and a 1.12s minimum normal timeout after the first WDI transition. Configuration requires connecting WDI to a µP GPIO that toggles during normal operation; no external components or register writes are needed. The MAX6721UTSYD3+ watchdog is enabled by default and requires no setup.
What is the reset output type and drive capability of MAX6721UTSYD3+?
MAX6721UTSYD3+ features an open-drain active-low RST output (Pin 1) with VOL ≤ 0.4V at ISINK = 3.2mA (VCC ≥ 4.5V). It requires an external pullup resistor to VCC1. This configuration allows wired-OR reset signaling and direct interface to bidirectional µP reset pins. The MAX6721UTSYD3+ does not provide push-pull or active-high reset variants.
Can MAX6721UTSYD3+ monitor a third voltage rail?
No, MAX6721UTSYD3+ is a dual-voltage supervisor and lacks RSTIN or PFI inputs. The 'Y' in its suffix denotes VCC2 = 3.075V, and 'S' denotes VCC1 = 4.625V; no third-monitoring capability is included. For triple-voltage supervision, consider MAX6723UTSYD3+ (with RSTIN) or MAX6728UTSYD3+ (with PFI/PFO), both in SOT23-6 package.
What is the minimum operating voltage guarantee for MAX6721UTSYD3+ reset functionality?
MAX6721UTSYD3+ guarantees valid reset output logic state down to VCC1 or VCC2 = 0.8V, as specified in the Absolute Maximum Ratings and Electrical Characteristics tables. This ensures deterministic reset assertion even during severe brownout conditions where supply rails dip near device operational limits. Below 0.8V, reset behavior is not characterized.
MAX6721UTSYD3+ 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:
- -
MAX6721UTSYD3+ FAQ
1.How can I place an order for MAX6721UTSYD3+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6721UTSYD3+ 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 MAX6721UTSYD3+ reliable?
The price and inventory of MAX6721UTSYD3+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6721UTSYD3+ is usually 5 days.
3.What payment methods are accepted for MAX6721UTSYD3+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6721UTSYD3+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6721UTSYD3+?
MAX6721UTSYD3+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6721UTSYD3+ 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 MAX6721UTSYD3+?
For technical support, including MAX6721UTSYD3+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6721UTSYD3+ requirements.
6.How does Aetrix verify that MAX6721UTSYD3+ is sourced from the original manufacturer or authorized distributors?
All MAX6721UTSYD3+ 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 MAX6721UTSYD3+ meets industry standards.
7.What is the process for return or replacement of MAX6721UTSYD3+?
All MAX6721UTSYD3+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX6721UTSYD3+, 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 MAX6721UTSYD3+ part is unused and in its original packaging.
Return procedure for MAX6721UTSYD3+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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