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Analog Devices Inc./Maxim Integrated MAX6728KASYD3+
- Part No.:
- MAX6728KASYD3+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- -
- Datasheet:
-
MAX6728KASYD3+.pdf
- Description:
- IC SUPERVISOR
- Quantity:
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Product details
Overview
MAX6728KASYD3+ 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 guaranteed reset validity down to VCC1 or VCC2 = 0.8V - used in telecom power sequencing and multivoltage server management.
For engineers reviewing the MAX6728KASYD3+ datasheet, MAX6728KASYD3+ pinout, MAX6728KASYD3+ application, or MAX6728KASYD3+ equivalent, key selection criteria include triple-supply monitoring capability, integrated power-fail comparator with PFO output, 210ms factory-set reset timeout, push-pull RST logic compatibility with bidirectional µP reset pins, and operation across –40°C to +85°C industrial temperature range.
Technical Context
The MAX6728KASYD3+ implements dual independent voltage comparators for VCC1 and VCC2, plus a dedicated power-fail comparator referenced to a 626.5mV internal bandgap, enabling simultaneous monitoring of primary, secondary, and auxiliary supply rails. Its reset assertion logic combines ORed fault conditions (VCC1/VCC2 undervoltage, PFI trip, MR low) with a monolithic timeout timer.
It features a push-pull active-low RST output referenced to VCC1 and an open-drain active-low PFO output referenced to VCC1, both asserted independently of each other; PFO deasserts immediately upon PFI recovery without timeout delay, while RST remains asserted for the full 210ms period after all monitored voltages exceed thresholds.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC1 Threshold | 4.625V (factory-trimmed, ±125mV tolerance) - sets precise brownout detection point for main system rail |
| VCC2 Threshold | 3.075V (factory-trimmed, ±75mV tolerance) - enables reliable monitoring of I/O or memory supply |
| PFI Threshold | 626.5mV (internal reference, ±15.5mV) - allows resistor-divider-based monitoring of third supply down to 0.62V |
| Reset Timeout | 210ms (minimum) - ensures sufficient hold time for processor initialization and peripheral stabilization |
| Supply Current | 14µA typical at 3.6V - minimizes quiescent load on battery-backed or low-power systems |
| Operating Temp | –40°C to +85°C - supports deployment in industrial and telecom equipment without derating |
| Reset Validity | Down to VCC1 or VCC2 = 0.8V - guarantees correct reset state during deep brownout or power ramp-down |
Pinout & Package
MAX6728KASYD3+ uses an 8-pin SOT23-8 package (3.0mm × 1.6mm × 1.1mm body, 0.65mm pitch), optimized for high-density PCB layouts in space-constrained telecom and embedded applications.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RST | Active-low push-pull reset output referenced to VCC1; asserts when any monitored supply fails or MR is pulled low |
| 2 | GND | System ground reference for all internal comparators and output drivers |
| 3 | MR | Active-low manual reset input with 50kΩ internal pullup to VCC1; forces reset on logic-low pulse ≥1µs |
| 4 | PFO | Active-low open-drain power-fail output referenced to VCC1; asserts immediately when PFI < 626.5mV, no timeout |
| 5 | VCC2 | Secondary supply input powering VCC2 comparator and RST2 logic (not used in MAX6728); must be connected for proper operation |
| 6 | VCC1 | Primary supply input powering core logic, RST driver, and PFO driver; defines reset output voltage levels |
| 7 | PFI | Power-fail monitor input with 626.5mV internal reference; high-impedance node for external resistor-divider network |
| 8 | RSTIN | Unused in MAX6728KASYD3+; tied internally to VCC1 per device variant configuration - not functional |
Key Features
| Feature | Design Value |
|---|---|
| Triple-supply monitoring | Simultaneous VCC1 (4.625V), VCC2 (3.075V), and PFI (626.5mV) supervision eliminates need for discrete comparators or additional supervisors |
| Independent PFO output | Open-drain PFO asserts instantly on power-fail event and deasserts immediately on recovery - enables real-time power-good signaling without reset interference |
| Push-pull RST with low-VCC validity | RST remains logically valid down to VCC1 = 0.8V and drives full rail-to-rail logic levels - ensures robust reset assertion during brownout transitions |
| 210ms factory-set timeout | Monolithic timeout period calibrated over temperature - removes external RC timing components and associated drift/error sources |
| Immunity to VCC transients | Withstands negative-going VCC glitches ≤20µs at 100mV overdrive - prevents spurious resets in noisy power environments |
Applications
| Telecom Power Sequencing | Server Board Management |
|---|---|
|
Use Scenario: Monitoring primary 4.8V DC/DC output, secondary 3.3V I/O rail, and backup battery voltage in LTE base station power modules. IC Role / Device Role / Timing Role: MAX6728KASYD3+ acts as centralized supervisor triggering coordinated reset and power-fail interrupt to BMC when any rail falls out of spec. Use Value: Eliminates three discrete voltage monitors and provides deterministic 210ms reset hold time for FPGA configuration and PHY initialization. |
Use Scenario: Ensuring safe boot sequence across CPU core (1.2V), memory (1.5V), and PCIe switch (3.3V) supplies in 1U rack server motherboards. IC Role / Device Role / Timing Role: MAX6728KASYD3+ monitors VCC1 (3.3V), VCC2 (1.5V), and PFI (derived from 12V input) to assert RST until all rails stabilize. Use Value: Guarantees reset remains asserted until all critical supplies reach regulation, preventing partial initialization and firmware corruption. |
| Industrial PLC Controller | Battery-Backed Data Logger |
|
Use Scenario: Supervising 24V field bus supply, 5V logic rail, and 3.3V MCU core in programmable logic controller I/O modules. IC Role / Device Role / Timing Role: MAX6728KASYD3+ uses PFI to monitor 24V input via resistor divider, asserting PFO to trigger early shutdown before brownout affects analog inputs. Use Value: Enables graceful firmware-controlled data save and watchdog-triggered safe state entry prior to complete power loss. |
Use Scenario: Managing power integrity in remote environmental sensor nodes powered by Li-ion battery with 3.6V nominal and 2.8V cutoff. IC Role / Device Role / Timing Role: MAX6728KASYD3+ monitors VCC1 (3.6V battery), VCC2 (3.3V LDO output), and PFI (battery voltage divider) to initiate controlled shutdown at 2.9V. Use Value: 14µA quiescent current extends battery life; 0.8V reset validity ensures reset remains asserted even during final discharge phase. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar triple-supply supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6729KASYD3+ | Same pinout and thresholds, but push-pull PFO instead of open-drain; higher drive strength (800µA sink) | Requires external pullup if interfacing to open-collector interrupt lines; better suited for driving LEDs or direct µP GPIO | Select MAX6729KASYD3+ when PFO must drive heavier loads or interface to CMOS inputs without pullup |
| TPS3808G33DBVR | Dual-supply monitor only (no PFI/PFO), 3.3V fixed VDD threshold, 200ms timeout, SOT23-6 package | Lacks third-supply monitoring and independent power-fail signaling; requires external circuitry for auxiliary rail supervision | Choose TPS3808G33DBVR only when system has exactly two rails and PFI functionality is unnecessary |
Compared with MAX6728KASYD3+, MAX6729KASYD3+ offers stronger PFO drive but less flexibility for open-drain interrupt buses, while TPS3808G33DBVR reduces cost and footprint but sacrifices triple-monitoring capability and independent PFO signaling - making MAX6728KASYD3+ optimal for systems requiring autonomous power-fail response without µP intervention.
Availability
MAX6728KASYD3+ is available at Aetrix Electronics and suitable for telecom infrastructure, server board management, and industrial PLC applications requiring stable component supply, long-term lifecycle support, and guaranteed performance across –40°C to +85°C.
Supply support for MAX6728KASYD3+ 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 demanding industrial, automotive, and communications applications.
The MAX6715–MAX6729 family delivers ultra-low-voltage, multi-rail supervisory functions in miniature SOT23 packages - engineered specifically for space-constrained, multivoltage systems where reliability, low quiescent current, and deterministic reset timing are critical.
FAQ
What is the exact reset threshold voltage for VCC1 on MAX6728KASYD3+?
The MAX6728KASYD3+ has a factory-trimmed VCC1 reset threshold of 4.625V, with a guaranteed tolerance of ±125mV over temperature. This value is encoded in the "SY" suffix per Maxim's Reset Voltage Threshold Suffix Guide and is confirmed in the Electrical Characteristics table under VTH1 parameter for the "S" threshold option.
Does MAX6728KASYD3+ support monitoring a third supply voltage via RSTIN?
No, MAX6728KASYD3+ does not use the RSTIN pin for third-supply monitoring. Per the Selector Guide and Pin Description, MAX6728 implements PFI/PFO for auxiliary monitoring - RSTIN is internally tied to VCC1 and nonfunctional. The device monitors VCC1, VCC2, and PFI exclusively.
What is the function of the PFO pin on MAX6728KASYD3+?
The PFO pin on MAX6728KASYD3+ is an active-low open-drain power-fail output that asserts immediately when the PFI input falls below 626.5mV and deasserts immediately when PFI rises above threshold - with no timeout delay. It is designed for real-time power-fail interrupts, not reset generation.
Can MAX6728KASYD3+ operate with VCC1 below 1.8V?
Yes, MAX6728KASYD3+ guarantees valid reset output logic states down to VCC1 = 0.8V, as specified in the Absolute Maximum Ratings and Detailed Description sections. Its internal comparators and push-pull RST driver remain fully functional across this extended low-voltage range.
What is the reset timeout period for MAX6728KASYD3+ and how is it set?
The MAX6728KASYD3+ has a factory-set minimum reset timeout period of 210ms, indicated by the "D3" suffix in the part number. This value is implemented using a monolithic timer circuit and is guaranteed over temperature without external components - eliminating timing uncertainty from RC networks.
MAX6728KASYD3+ 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:
- -
MAX6728KASYD3+ FAQ
1.How can I place an order for MAX6728KASYD3+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6728KASYD3+ 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 MAX6728KASYD3+ reliable?
The price and inventory of MAX6728KASYD3+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6728KASYD3+ is usually 5 days.
3.What payment methods are accepted for MAX6728KASYD3+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6728KASYD3+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6728KASYD3+?
MAX6728KASYD3+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6728KASYD3+ 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 MAX6728KASYD3+?
For technical support, including MAX6728KASYD3+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6728KASYD3+ requirements.
6.How does Aetrix verify that MAX6728KASYD3+ is sourced from the original manufacturer or authorized distributors?
All MAX6728KASYD3+ 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 MAX6728KASYD3+ meets industry standards.
7.What is the process for return or replacement of MAX6728KASYD3+?
All MAX6728KASYD3+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX6728KASYD3+, 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 MAX6728KASYD3+ part is unused and in its original packaging.
Return procedure for MAX6728KASYD3+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MAX6728KASYD3+ Tags
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MIC826SYMT-TR
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