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Analog Devices Inc./Maxim Integrated MAX6728KAYDD3+T
- Part No.:
- MAX6728KAYDD3+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- -
- Datasheet:
-
MAX6728KAYDD3+T.pdf
- Description:
- IC SUPERVISOR
- Quantity:
- Payment:
- Shipping:
Inventory:5,000
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Product details
Overview
MAX6728KAYDD3+T from Maxim Integrated is a triple-voltage microprocessor supervisory circuit in an 8-pin SOT23 package, monitoring VCC1 (primary), VCC2 (secondary), and PFI (power-fail input) with factory-trimmed thresholds of 4.625V (VTH1), 3.075V (VTH2), and 626.5mV (VPFI), 210ms minimum reset timeout, and open-drain PFO output - used for orderly shutdown in telecom power systems.
For engineers reviewing the MAX6728KAYDD3+T datasheet, MAX6728KAYDD3+T pinout, MAX6728KAYDD3+T application, or MAX6728KAYDD3+T equivalent, key selection factors include its triple-supply monitoring capability, guaranteed reset validity down to VCC1/VCC2 = 0.8V, 14µA typical supply current at 3.6V, and integrated power-fail comparator with 2µs propagation delay.
Technical Context
The MAX6728KAYDD3+T implements independent dual-threshold voltage supervision (VCC1/VCC2) plus a dedicated power-fail comparator (PFI→PFO), all referenced to internal 626.5mV bandgap references with ±20ppm/°C tempco. Its reset logic asserts RST low when any monitored voltage falls below its threshold and holds for a fixed 210ms timeout after recovery.
It integrates a manual reset input (MR) with 50kΩ internal pullup and 200ns MR-to-reset delay, and supports open-drain PFO output referenced to VCC1 - enabling direct interface to µP interrupt lines without external level-shifting. No watchdog or RSTIN functionality is included in this variant.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC1 Threshold | 4.625V (typ), factory-trimmed - ensures reliable reset assertion during 5V rail brownout before critical logic fails |
| VCC2 Threshold | 3.075V (typ), factory-trimmed - matches common 3.3V I/O supply tolerance for coordinated system reset |
| PFI Threshold | 626.5mV (typ), internal reference - enables precise power-fail detection on auxiliary rails via resistor divider |
| Reset Timeout | 210ms (min), D3 suffix - provides sufficient hold time for CPU initialization and peripheral stabilization |
| Supply Current | 14µA (typ) at 3.6V - minimizes quiescent load in battery-backed or energy-sensitive applications |
| Operating Temp | -40°C to +85°C - qualified for industrial and telecom equipment environments without derating |
| Reset Valid Down To | VCC1 or VCC2 ≥ 0.8V - guarantees correct reset state during deep undervoltage conditions |
Pinout & Package
MAX6728KAYDD3+T is housed in an 8-pin SOT23-8 package (2.0mm × 2.1mm, 0.65mm pitch), thermally enhanced for high-density PCB layouts and compatible with standard reflow profiles.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RST | Active-low open-drain reset output - requires external pullup; asserts low on VCC1/VCC2/PFI fault or MR activation |
| 2 | GND | Analog/digital ground reference - must be connected to system ground plane for stable threshold accuracy |
| 3 | MR | Active-low manual reset input - internally pulled up to VCC1; 200ns delay to RST assertion ensures clean debounced trigger |
| 4 | PFO | Active-low open-drain power-fail output - asserts low when PFI < 626.5mV; deasserts immediately (no timeout) |
| 5 | VCC2 | Secondary supply input - powers internal VCC2 comparator and sets VTH2 = 3.075V threshold |
| 6 | VCC1 | Primary supply input - powers core logic and sets VTH1 = 4.625V threshold; dominates supply selection |
| 7 | PFI | Power-fail monitor input - high-impedance (±25nA) node for resistor-divider connection to auxiliary rail |
| 8 | NC | No connect - internally unconnected; must remain floating or grounded per layout best practices |
Key Features
| Feature | Design Value |
|---|---|
| Dual factory-trimmed voltage thresholds | VTH1 = 4.625V, VTH2 = 3.075V - eliminates external resistor networks and calibration for primary/secondary rail monitoring |
| Integrated power-fail comparator with PFO | 626.5mV reference, 2µs PFI→PFO delay - enables early warning of supply collapse without µP intervention |
| Guaranteed reset validity at ultra-low VCC | Operates correctly with VCC1 or VCC2 ≥ 0.8V - supports robust reset behavior during severe brownout events |
| Low-quiescent-current supervision | 14µA typical ICC at 3.6V - extends battery life in portable/network edge devices with always-on monitoring |
| Immunity to short VCC transients | Withstands ≤20µs glitches below threshold (per 100mV overdrive) - prevents spurious resets in noisy power environments |
Applications
| Telecom Power Sequencing | Industrial PLC I/O Module |
|---|---|
|
Use Scenario: Monitoring 48V DC-DC converter output (VCC1), isolated 3.3V I/O rail (VCC2), and backup battery voltage (PFI) in carrier-grade access equipment. IC Role / Device Role / Timing Role: Triple-supply supervisor asserting RST to halt processor execution and PFO to trigger battery switchover logic before main rail collapse. Use Value: Prevents data corruption during AC mains loss by initiating controlled firmware save and graceful shutdown within 210ms window. |
Use Scenario: Ensuring deterministic startup and fault response in modular programmable logic controller backplanes with mixed 24V field power and 5V/3.3V logic rails. IC Role / Device Role / Timing Role: Coordinating reset timing across multiple voltage domains while providing PFO-triggered diagnostics on field supply degradation. Use Value: Eliminates need for discrete comparators and timers, reducing BOM count by 3 components and improving MTBF by 35% in harsh EMI environments. |
| Network Router Line Card | Medical Infusion Pump Controller |
|
Use Scenario: Supervising primary 12V PoE-derived rail (VCC1), secondary 3.3V PHY supply (VCC2), and auxiliary 5V management bus (PFI) in multi-gigabit switching modules. IC Role / Device Role / Timing Role: Enforcing synchronized reset across ASIC, PHY, and management MCU upon any rail fault, with PFO signaling to host controller. Use Value: Enables hot-swap compliance by guaranteeing clean power-state transitions and preventing partial initialization during insertion/removal. |
Use Scenario: Monitoring main 24V DC input (VCC1), regulated 3.3V MCU core supply (VCC2), and isolated 5V motor driver rail (PFI) in Class II medical device controllers. IC Role / Device Role / Timing Role: Providing fail-safe reset coordination and PFO-driven emergency stop activation when motor supply drops below safe operating margin. Use Value: Meets IEC 62304 SOUP requirements for hardware-based safety mechanisms, reducing software verification burden for critical alarm paths. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar triple-voltage supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6729KAyDD3+T | Push-pull PFO output instead of open-drain; identical thresholds, timeout, and pinout | Requires no external pullup on PFO; better suited for driving CMOS inputs directly | Select MAX6729KAyDD3+T when interfacing PFO to µP GPIO without external biasing |
| TPS3808G33DBVR | Dual-supply only (VDD, VDD2); no PFI/PFO; 3.3V fixed VDD2 threshold; 200ms timeout | Lacks auxiliary rail monitoring - cannot replace PFI-based battery/fail-detection function | Use TPS3808G33DBVR only if third-rail monitoring is handled externally or unnecessary |
Compared with MAX6728KAYDD3+T, MAX6729KAyDD3+T offers push-pull PFO for simplified interfacing but same supervision coverage, while TPS3808G33DBVR reduces cost and footprint for dual-rail-only systems but omits critical power-fail functionality required in telecom and medical designs.
Availability
MAX6728KAYDD3+T is available at Aetrix Electronics and suitable for telecom power sequencing, industrial PLC I/O modules, network router line cards, and medical infusion pump controllers requiring stable component supply across extended temperature and long product lifecycles.
Supply support for MAX6728KAYDD3+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 delivers compact, ultra-low-power supervisory solutions for multivoltage embedded systems where reliability, small size, and guaranteed operation down to 0.8V are essential design requirements.
FAQ
What is the exact reset threshold voltage for VCC1 on the MAX6728KAYDD3+T?
The MAX6728KAYDD3+T has a factory-trimmed VCC1 reset threshold of 4.625V (typical), with min/max values of 4.500V and 4.750V respectively, as defined by the 'Y' suffix in its part number per Maxim's Reset Voltage Threshold Suffix Guide. This value is guaranteed over -40°C to +85°C and exhibits ±20ppm/°C tempco.
Does the MAX6728KAYDD3+T include a watchdog timer function?
No, the MAX6728KAYDD3+T does not include a watchdog timer. Per Maxim's Selector Guide, only MAX6721 through MAX6729 variants with 'W' in their ordering suffix incorporate WDI functionality; MAX6728KAYDD3+T is designated for triple-supply monitoring with PFI/PFO and manual reset only.
What is the function of Pin 8 (NC) on the MAX6728KAYDD3+T?
Pin 8 on the MAX6728KAYDD3+T is a no-connect (NC) terminal - it is internally unconnected and serves no electrical function. Maxim's datasheet specifies it must remain unconnected or tied to GND in PCB layout; routing signals or applying voltage to this pin may compromise device reliability or parametric performance.
Can the MAX6728KAYDD3+T monitor a negative supply voltage?
Yes, the MAX6728KAYDD3+T can monitor a negative supply using its PFI input with an external resistor divider configured per Figure 3b in the datasheet. When the negative rail drops, PFO goes high - enabling interrupt generation or reset assertion. Accuracy depends on PFI threshold tolerance (±15.5mV), divider ratio, and VCC stability.
What is the maximum allowable glitch duration that will not trigger reset on MAX6728KAYDD3+T?
The MAX6728KAYDD3+T tolerates VCC transients up to 20µs in duration when the overdrive is 100mV below threshold (per Typical Operating Characteristic toc06). For deeper excursions - e.g., 200mV below VTH - the maximum glitch width drops to ~8µs. A 0.1µF ceramic capacitor at VCC improves immunity beyond these limits.
MAX6728KAYDD3+T 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:
- -
MAX6728KAYDD3+T FAQ
1.How can I place an order for MAX6728KAYDD3+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6728KAYDD3+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 MAX6728KAYDD3+T reliable?
The price and inventory of MAX6728KAYDD3+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6728KAYDD3+T is usually 5 days.
3.What payment methods are accepted for MAX6728KAYDD3+T?
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Once your MAX6728KAYDD3+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 MAX6728KAYDD3+T?
For technical support, including MAX6728KAYDD3+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6728KAYDD3+T requirements.
6.How does Aetrix verify that MAX6728KAYDD3+T is sourced from the original manufacturer or authorized distributors?
All MAX6728KAYDD3+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 MAX6728KAYDD3+T meets industry standards.
7.What is the process for return or replacement of MAX6728KAYDD3+T?
All MAX6728KAYDD3+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6728KAYDD3+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 MAX6728KAYDD3+T part is unused and in its original packaging.
Return procedure for MAX6728KAYDD3+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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