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Analog Devices Inc./Maxim Integrated MAX6728KAYDD3+
- Part No.:
- MAX6728KAYDD3+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- -
- Datasheet:
-
MAX6728KAYDD3+.pdf
- Description:
- IC SUPERVISOR
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
MAX6728KAYDD3+ 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). It provides open-drain active-low RST and PFO outputs, manual reset input (MR), and a 210ms (min) reset timeout period. It ensures reliable system reset in multivoltage embedded power rails for telecom and industrial equipment.
For engineers reviewing the MAX6728KAYDD3+ datasheet, MAX6728KAYDD3+ pinout, MAX6728KAYDD3+ application, or MAX6728KAYDD3+ equivalent, key selection criteria include its triple-supply monitoring capability, guaranteed reset validity down to VCC1/VCC2 = 0.8V, 14µA typical supply current at 3.6V, immunity to short VCC transients, and compatibility with battery-operated and thermally demanding environments (-40°C to +85°C).
Technical Context
The MAX6728KAYDD3+ integrates three independent voltage comparators: one for VCC1 (4.625V threshold), one for VCC2 (3.075V threshold), and one for PFI (626.5mV internal reference). Reset assertion occurs if any monitored voltage falls below its threshold, and reset remains asserted for ≥210ms after all voltages recover.
It features an open-drain PFO output that deasserts immediately upon PFI recovery-without timeout-and an open-drain RST output asserted on VCC1/VCC2/PFI fault or MR low. The device uses BiCMOS process (1072 transistors) and guarantees correct reset logic state when either VCC1 or VCC2 ≥ 0.8V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC1 Threshold | 4.625V (factory-trimmed, ±125mV tolerance); sets primary supply brownout detection point for 5V rail systems. |
| VCC2 Threshold | 3.075V (factory-trimmed, ±75mV tolerance); enables reliable monitoring of 3.3V auxiliary or I/O supply rails. |
| PFI Threshold | 626.5mV (internal reference); allows precise external resistor-divider setup for custom power-fail trip points on any supply. |
| Reset Timeout | 210ms (minimum); ensures µP completes full initialization before release, avoiding premature execution. |
| Supply Current | 14µA (typ at 3.6V); enables ultra-low-power operation in battery-backed or energy-constrained systems. |
| Operating Temp | -40°C to +85°C; supports deployment in industrial control cabinets, outdoor telecom nodes, and automotive-adjacent applications. |
| Reset Valid Down To | VCC1 or VCC2 ≥ 0.8V; guarantees deterministic reset behavior during deep brownout or soft-start conditions. |
Pinout & Package
Package: 8-pin SOT23 (SOT23-8), surface-mount, lead-free (indicated by '+' suffix), footprint-compatible with industry-standard 8-pin SOT23 layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RST | Active-low open-drain reset output; requires external pullup; asserts when VCC1/VCC2/PFI fault or MR low. |
| 2 | GND | System ground reference for all internal comparators and logic; must be low-impedance connection. |
| 3 | MR | Active-low manual reset input; internal 50kΩ pullup to VCC1; debounced by design; no external RC needed. |
| 4 | PFO | Active-low open-drain power-fail output; asserts immediately when PFI < 626.5mV; no timeout delay. |
| 5 | VCC2 | Secondary supply input (3.075V threshold monitor); powers internal circuitry when > VCC1 or used as reference for RST2 (not present in MAX6728). |
| 6 | VCC1 | Primary supply input (4.625V threshold monitor); main power source and reference for RST/PFO drivers. |
| 7 | PFI | Power-fail comparator input; high-impedance (±25nA); connects to resistor divider for custom trip voltage. |
| 8 | NC | No connect; internally unconnected; must remain floating or tied to GND per layout best practice. |
Key Features
| Feature | Design Value |
|---|---|
| Triple-voltage monitoring | Simultaneous supervision of VCC1 (4.625V), VCC2 (3.075V), and PFI (626.5mV ref) eliminates need for discrete comparators or multiple supervisors. |
| Open-drain PFO with immediate response | PFO asserts/deasserts without timeout-enabling real-time power-fail interrupt generation to µP without reset interference. |
| Guaranteed reset validity at 0.8V | Ensures clean, predictable reset signaling even during severe brownout or slow power ramp-up, critical for flash programming safety. |
| 14µA typical supply current | Reduces quiescent load on backup batteries or low-power rails, extending hold-up time in UPS or RTC subsystems. |
| Immunity to short VCC transients | Rejects sub-20µs glitches (per typical operating curves), preventing spurious resets in electrically noisy industrial environments. |
Applications
| Telecom Line Cards | Industrial PLC I/O Modules |
|---|---|
Use Scenario: Monitoring primary 5V backplane supply, secondary 3.3V FPGA I/O rail, and -48V DC/DC converter output via PFI divider in carrier-grade line cards. IC Role / Device Role / Timing Role: Triple-supply supervisor asserting RST on any rail failure and generating immediate PFO interrupt for graceful service handover. Use Value: Prevents corrupted packet forwarding during partial power loss and enables firmware-triggered failover within 210ms. | Use Scenario: Supervising 24V field bus supply (via PFI divider), 5V controller rail (VCC1), and 3.3V sensor interface rail (VCC2) in modular PLC chassis. IC Role / Device Role / Timing Role: Centralized reset arbiter ensuring coordinated restart of CPU, FPGA, and analog front-end after undervoltage event. Use Value: Eliminates need for three separate supervisors, reducing BOM count and PCB area while guaranteeing synchronized reset timing. |
| Medical Infusion Pumps | Set-Top Box Power Sequencing |
Use Scenario: Monitoring main 12V battery-derived rail (VCC1), isolated 3.3V MCU supply (VCC2), and backup coin-cell voltage (PFI) in battery-powered infusion devices. IC Role / Device Role / Timing Role: Safety-critical reset generator with guaranteed operation down to 0.8V to prevent motor runaway during battery sag. Use Value: Meets IEC 62304 Class C software safety requirements by ensuring deterministic reset under worst-case brownout. | Use Scenario: Coordinating power-up sequence of SoC (VCC1), DDR memory (VCC2), and tuner IC (PFI-monitored 1.8V rail) in consumer STB designs. IC Role / Device Role / Timing Role: Single-chip sequencer enforcing minimum 210ms hold time before releasing reset to avoid SoC boot failure. Use Value: Replaces discrete RC timers and logic gates, improving timing accuracy and eliminating component aging drift. |
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+ | Push-pull RST and PFO outputs instead of open-drain; identical thresholds, timeout, and pinout except PFO drive strength. | Requires no external pullup on PFO; better suited for driving LEDs or level-shifting into CMOS inputs directly. | Select MAX6729KAyDD3+ when PFO must sink/source current without external components; otherwise MAX6728KAYDD3+ offers greater flexibility with pullup choice. |
| TPS3808G33DBVR | Dual-supply monitor only (VDD, VDD1); no PFI input; fixed 3.3V VDD threshold; 200ms timeout; SOT23-6 package. | Lacks third-monitor capability and power-fail interrupt; suitable only where only two rails require supervision. | Choose TPS3808G33DBVR for cost-sensitive dual-rail apps without PFI need; MAX6728KAYDD3+ is required for true triple-voltage or power-fail alerting. |
Compared with MAX6729KAyDD3+, MAX6728KAYDD3+ provides open-drain PFO for flexible interfacing but requires a pullup; compared with TPS3808G33DBVR, it adds critical PFI functionality and third-rail monitoring-making it the only option for applications requiring coordinated triple-supply fault detection and immediate power-fail signaling.
Availability
MAX6728KAYDD3+ is available at Aetrix Electronics and suitable for telecom infrastructure, industrial PLCs, and medical infusion pumps requiring stable component supply across extended temperature and long product lifecycles.
Supply support for MAX6728KAYDD3+ 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 and mixed-signal ICs for power, sensing, and connectivity in harsh and space-constrained environments.
The MAX6715–MAX6729 family delivers ultra-low-voltage, multi-rail supervisory circuits optimized for reliability-critical embedded systems where simultaneous monitoring of primary, secondary, and auxiliary supplies is mandatory.
FAQ
What is the exact reset threshold voltage for VCC1 on the MAX6728KAYDD3+?
The MAX6728KAYDD3+ has a factory-trimmed VCC1 reset threshold of 4.625V (with ±125mV tolerance over temperature), corresponding to the 'Y' suffix in the part number per Maxim's Reset Voltage Threshold Suffix Guide. This value is measured at the VCC1 pin and triggers reset assertion when VCC1 falls below this level.
Does the MAX6728KAYDD3+ provide a watchdog timer function?
No, the MAX6728KAYDD3+ does not include a watchdog timer. Per Maxim's Selector Guide, only MAX6721–MAX6729 variants with 'W' in the functional suffix (e.g., MAX6728W) integrate watchdog input; the MAX6728KAYDD3+ is designated for triple-voltage supervision with PFI/PFO only.
How is the power-fail threshold set on the MAX6728KAYDD3+?
The MAX6728KAYDD3+ uses an internal 626.5mV reference for the PFI comparator. To set a custom power-fail trip point, connect PFI to a resistor divider between the supply to monitor and ground-the divider ratio determines the trip voltage using VTRIP = 626.5mV × (R1 + R2)/R2.
What is the reset timeout period of the MAX6728KAYDD3+?
The MAX6728KAYDD3+ has a minimum reset timeout period of 210ms, indicated by the 'D3' suffix in the part number per Maxim's Reset Timeout Period Suffix Guide. This duration is guaranteed over the full -40°C to +85°C operating range and begins after all monitored supplies exceed their thresholds.
Can the MAX6728KAYDD3+ monitor negative supply voltages?
Yes-the MAX6728KAYDD3+ can monitor negative supplies using the PFI input with an appropriate resistor divider configuration, as shown in Figure 3b of the datasheet. When the negative supply drops, PFO asserts low; accuracy depends on PFI threshold tolerance, divider resistor matching, and VCC stability.
MAX6728KAYDD3+ 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+ FAQ
1.How can I place an order for MAX6728KAYDD3+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6728KAYDD3+ 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+ reliable?
The price and inventory of MAX6728KAYDD3+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6728KAYDD3+ is usually 5 days.
3.What payment methods are accepted for MAX6728KAYDD3+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6728KAYDD3+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6728KAYDD3+?
MAX6728KAYDD3+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6728KAYDD3+ 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+?
For technical support, including MAX6728KAYDD3+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6728KAYDD3+ requirements.
6.How does Aetrix verify that MAX6728KAYDD3+ is sourced from the original manufacturer or authorized distributors?
All MAX6728KAYDD3+ 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+ meets industry standards.
7.What is the process for return or replacement of MAX6728KAYDD3+?
All MAX6728KAYDD3+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX6728KAYDD3+, 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+ part is unused and in its original packaging.
Return procedure for MAX6728KAYDD3+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MAX6728KAYDD3+ Tags
-
MIC826SYMT-TR
Microchip Technology
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APX803S-31SA-7
Diodes Incorporated
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APX803L20-29SA-7
Diodes Incorporated
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TPS3828-33DBVR
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V6340RSP3B+
EM Microelectronic
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EM6325CXSP5B-2.9+
EM Microelectronic
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MCP120T-300I/TT
Microchip Technology
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MCP130T-315I/TT
Microchip Technology
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MCP120T-475I/TT
Microchip Technology
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MCP111T-300E/TT
Microchip Technology
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MCP120T-315I/TT
Microchip Technology
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MCP809T-315I/TT
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