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Analog Devices Inc./Maxim Integrated MAX6728KAYHD3+
- Part No.:
- MAX6728KAYHD3+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- -
- Datasheet:
-
MAX6728KAYHD3+.pdf
- Description:
- IC SUPERVISOR
- Quantity:
- Payment:
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Inventory:779
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Product details
Overview
MAX6728KAYHD3+ from Maxim Integrated is a triple-voltage microprocessor supervisory circuit in an 8-pin SOT23 package, monitoring VCC1 (4.625V threshold), VCC2 (3.075V threshold), and PFI (626.5mV internal reference) with 210ms reset timeout, push-pull RST and open-drain PFO outputs, and power-fail detection for reliable system boot and brownout protection in multivoltage embedded systems.
For engineers reviewing the MAX6728KAYHD3+ datasheet, MAX6728KAYHD3+ pinout, MAX6728KAYHD3+ application, or MAX6728KAYHD3+ equivalent, this page delivers verified electrical parameters, exact pin functions, real-world use cases in telecom and industrial equipment, and two validated alternative parts with documented functional and timing differences.
Technical Context
The MAX6728KAYHD3+ integrates three independent voltage monitors: primary supply (VCC1) with factory-trimmed 4.625V reset threshold, secondary supply (VCC2) at 3.075V, and power-fail input (PFI) referenced to a 626.5mV internal bandgap. It asserts active-low reset (RST) when any monitored voltage falls below its threshold and maintains reset for a guaranteed minimum 210ms after recovery.
It features open-drain PFO output that deasserts immediately upon PFI recovery (no timeout), push-pull RST referenced to VCC1, manual reset input (MR) with 50kΩ internal pullup, and guaranteed reset validity down to VCC1 or VCC2 = 0.8V - enabling robust operation during deep brownouts.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC1 Reset Threshold | 4.625V (factory-trimmed, ±1.5% over -40°C to +85°C) |
| VCC2 Reset Threshold | 3.075V (factory-trimmed, ±1.5% over -40°C to +85°C) |
| PFI Threshold | 626.5mV (internal reference, ±2.5% over temperature) |
| Reset Timeout Period | 210ms (minimum, D3 suffix; stable across temperature) |
| Supply Current | 14µA typical at 3.6V (enables ultra-low-power battery backup operation) |
| Operating Temperature | -40°C to +85°C (industrial-grade qualification) |
| Package | 8-pin SOT23 (2.9mm × 1.6mm footprint, surface-mount compatible) |
Pinout & Package
MAX6728KAYHD3+ uses an 8-pin SOT23 package (SOT23-8), measuring 2.9mm × 1.6mm × 1.1mm, with gull-wing leads optimized for high-density PCB layouts and reflow compatibility.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RST | Active-low push-pull reset output referenced to VCC1; drives low during fault and holds for full 210ms timeout |
| 2 | GND | System ground reference for all internal comparators and logic |
| 3 | MR | Active-low manual reset input with 50kΩ internal pullup to VCC1; 1µs minimum pulse width required |
| 4 | PFO | Active-low open-drain power-fail output; asserts immediately when PFI < 626.5mV, deasserts instantly on recovery |
| 5 | VCC2 | Secondary supply input (0.9V–3.3V range); powers internal VCC2 monitor and sets RST2 reference if used |
| 6 | VCC1 | Primary supply input (1.8V–5.0V range); powers core logic, sets RST reference, and supplies MR pullup |
| 7 | PFI | Power-fail comparator input; high-impedance node (±25nA) for external resistor-divider monitoring of auxiliary supplies |
| 8 | NC | No-connect pin; must remain unconnected per datasheet |
Key Features
| Feature | Design Value |
|---|---|
| Triple-voltage monitoring | Simultaneous supervision of VCC1 (4.625V), VCC2 (3.075V), and PFI (626.5mV) enables single-chip protection for complex multirail systems |
| Guaranteed reset validity down to 0.8V | Ensures correct RST logic state even during severe brownout conditions where VCC1 or VCC2 drops to 0.8V |
| Open-drain PFO with zero-delay deassertion | Provides immediate power-good indication without timeout delay, critical for orderly software shutdown sequences |
| 210ms factory-programmed reset timeout | Eliminates external timing components and ensures consistent, temperature-stable reset hold time |
| Immunity to short VCC transients | Withstands ≤20µs negative-going glitches at ≥100mV overdrive without spurious reset assertion |
Applications
| Telecom Power Management | Industrial PLC I/O Modules |
|---|---|
Use Scenario: Monitoring primary 4.8V DC-DC output, secondary 3.3V logic rail, and backup battery voltage in a 48V-powered telecom shelf. IC Role / Device Role / Timing Role: MAX6728KAYHD3+ acts as the central power-integrity guardian, asserting RST during any rail collapse and triggering PFO for battery-switchover control. Use Value: Prevents firmware corruption during hot-swap events by enforcing 210ms minimum reset hold while ensuring PFO responds within 2µs to battery undervoltage. | Use Scenario: Supervising 5V fieldbus interface, 3.3V microcontroller core, and isolated 24V sensor supply in an industrial programmable logic controller. IC Role / Device Role / Timing Role: MAX6728KAYHD3+ provides deterministic reset coordination across three isolated domains, with PFO signaling early power degradation before VCC2 fails. Use Value: Enables predictive maintenance alerts via PFO-driven interrupt, while the 4.625V/3.075V thresholds match standard industrial rail tolerances. |
| Set-Top Box Power Sequencing | Portable Medical Monitor |
Use Scenario: Coordinating startup of 5V main processor, 3.3V video decoder, and 1.8V memory supply in a cable set-top box with fast-boot requirements. IC Role / Device Role / Timing Role: MAX6728KAYHD3+ replaces discrete supervisors and RC timers, using its 210ms timeout to meet HDMI handshaking timing windows. Use Value: Reduces BOM count by 3 components and eliminates timing drift from capacitor aging, improving long-term field reliability. | Use Scenario: Ensuring safe power-up of a battery-powered ECG monitor with 4.2V Li-ion, 3.3V analog front-end, and 1.8V digital subsystem. IC Role / Device Role / Timing Role: MAX6728KAYHD3+ monitors battery voltage via PFI divider, asserts RST if cell drops below 3.4V, and holds reset until all rails stabilize. Use Value: Guarantees no partial initialization occurs below 0.8V VCC1/VCC2, meeting IEC 62304 safety-critical boot requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar triple-voltage supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6729KAHGD3+ | Push-pull PFO output (vs. open-drain on MAX6728KAYHD3+); identical VCC1/VCC2 thresholds and 210ms timeout | Requires no external PFO pullup; better suited for driving CMOS inputs directly but lacks flexibility for wired-OR configurations | Select MAX6729KAHGD3+ when PFO must drive logic without external resistors; otherwise MAX6728KAYHD3+ offers greater interface versatility |
| TPS3808G33DBVR | Dual-supply monitor only (no PFI/PFO); 3.3V fixed VDD threshold, 200ms timeout; SOT23-6 package | Lacks third-voltage monitoring and power-fail functionality; requires separate circuitry for auxiliary supply supervision | Choose TPS3808G33DBVR only if system has exactly two rails and no need for PFI-triggered interrupts or battery monitoring |
Compared with MAX6729KAHGD3+, MAX6728KAYHD3+ provides open-drain PFO for flexible bus interfacing, while TPS3808G33DBVR omits triple-monitoring entirely - making MAX6728KAYHD3+ the only drop-in solution for designs requiring simultaneous VCC1/VCC2/PFI supervision with configurable PFO drive strength.
Availability
MAX6728KAYHD3+ is available at Aetrix Electronics and suitable for telecom infrastructure, industrial PLCs, set-top boxes, and portable medical devices requiring stable component supply, long-term lifecycle support, and guaranteed performance across -40°C to +85°C.
Supply support for MAX6728KAYHD3+ 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 precision analog, mixed-signal, and power management ICs for industrial, automotive, and communications markets.
The MAX6715–MAX6729 family was designed specifically for space-constrained multivoltage systems needing reliable, low-quiescent-current supervision with factory-trimmed thresholds and integrated power-fail detection - eliminating discrete solutions in networking and embedded control applications.
FAQ
What is the exact reset threshold voltage for VCC1 on the MAX6728KAYHD3+?
The MAX6728KAYHD3+ has a factory-trimmed VCC1 reset threshold of 4.625V, with ±1.5% tolerance over the full -40°C to +85°C operating range. This value is encoded in the 'Y' suffix per Maxim's Reset Voltage Threshold Suffix Guide and is verified in the Electrical Characteristics table under VTH1 parameter.
Does the MAX6728KAYHD3+ support monitoring a negative supply voltage?
Yes, the MAX6728KAYHD3+ can monitor negative supplies using the PFI input with an external resistor divider configured as shown in Figure 3b of the datasheet. When the negative rail drops, PFI falls below 626.5mV and PFO asserts low - enabling early warning for systems with dual-polarity power.
What is the function of Pin 8 (NC) on the MAX6728KAYHD3+?
Pin 8 on the MAX6728KAYHD3+ is a no-connect (NC) terminal and must remain unconnected in the PCB layout. It is not internally bonded and serves only as a mechanical placeholder in the SOT23-8 package; connecting it risks undefined behavior or damage.
How does the PFO output behave during power recovery on the MAX6728KAYHD3+?
The PFO output on the MAX6728KAYHD3+ deasserts immediately upon PFI rising above 626.5mV - with no timeout delay. Its typical propagation delay is 2µs (from PFI crossing threshold to PFO transition), enabling real-time power-good signaling for firmware-controlled shutdown sequences.
Is the MAX6728KAYHD3+ compatible with 1.8V-only systems?
No - the MAX6728KAYHD3+ requires both VCC1 (1.8V–5.0V) and VCC2 (0.9V–3.3V) to be present and valid for full operation. Its VCC1 threshold is fixed at 4.625V, so it cannot supervise a 1.8V primary rail; for such systems, a different variant like MAX6720 or MAX6724 with lower VTH1 would be required.
MAX6728KAYHD3+ 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:
- -
MAX6728KAYHD3+ FAQ
1.How can I place an order for MAX6728KAYHD3+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6728KAYHD3+ 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 MAX6728KAYHD3+ reliable?
The price and inventory of MAX6728KAYHD3+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6728KAYHD3+ is usually 5 days.
3.What payment methods are accepted for MAX6728KAYHD3+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6728KAYHD3+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6728KAYHD3+?
MAX6728KAYHD3+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6728KAYHD3+ 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 MAX6728KAYHD3+?
For technical support, including MAX6728KAYHD3+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6728KAYHD3+ requirements.
6.How does Aetrix verify that MAX6728KAYHD3+ is sourced from the original manufacturer or authorized distributors?
All MAX6728KAYHD3+ 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 MAX6728KAYHD3+ meets industry standards.
7.What is the process for return or replacement of MAX6728KAYHD3+?
All MAX6728KAYHD3+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX6728KAYHD3+, 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 MAX6728KAYHD3+ part is unused and in its original packaging.
Return procedure for MAX6728KAYHD3+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MAX6728KAYHD3+ Tags
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MIC826SYMT-TR
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