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Analog Devices Inc./Maxim Integrated MAX6728KASDD3+
- Part No.:
- MAX6728KASDD3+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- -
- Datasheet:
-
MAX6728KASDD3+.pdf
- Description:
- IC SUPERVISOR
- Quantity:
- Payment:
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Product details
Overview
MAX6728KASDD3+ 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 - used in telecom power systems to ensure orderly shutdown during brownout events.
For engineers reviewing the MAX6728KASDD3+ datasheet, MAX6728KASDD3+ pinout, MAX6728KASDD3+ application, or MAX6728KASDD3+ equivalent, this page delivers verified electrical specs, exact pin functions, real-world use cases in multivoltage embedded systems, and two validated alternative parts with documented functional differences.
Technical Context
The MAX6728KASDD3+ 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 210ms after recovery.
It features open-drain PFO output tied to PFI comparator (2µs delay), 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 in low-voltage brownout conditions without external support circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC1 Threshold | 4.625V (factory-trimmed, ±125mV tolerance) - ensures reliable reset assertion on 5V rail undervoltage |
| VCC2 Threshold | 3.075V (factory-trimmed, ±75mV tolerance) - matches common 3.3V I/O supply monitoring |
| PFI Threshold | 626.5mV (internal reference) - enables precise external resistor-divider setup for custom power-fail trip points |
| Reset Timeout | 210ms (min) - provides sufficient hold time for processor initialization and peripheral stabilization |
| Supply Current | 14µA (typ at 3.6V) - minimizes quiescent load in battery-backed or energy-sensitive systems |
| Operating Temp | -40°C to +85°C - qualified for industrial and telecom equipment environments |
| Package | 8-pin SOT23 - surface-mount footprint compatible with high-density PCB layouts and automated assembly |
Pinout & Package
MAX6728KASDD3+ uses an 8-pin SOT23 package (3.0mm × 1.6mm × 1.1mm height), optimized for space-constrained applications requiring triple-supply monitoring and power-fail signaling.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RST | Active-low push-pull reset output referenced to VCC1; drives low during fault and holds for 210ms post-recovery |
| 2 | GND | System ground reference for all internal comparators and logic |
| 3 | MR | Active-low manual reset input with 50kΩ internal pullup to VCC1; initiates reset on logic-low pulse ≥1µs |
| 4 | PFO | Active-low open-drain power-fail output; asserts immediately (2µs delay) when PFI < 626.5mV, no timeout |
| 5 | VCC2 | Secondary supply input (0.9V–3.3V range); powers internal VCC2 monitor and RST2 logic (not used in MAX6728) |
| 6 | VCC1 | Primary supply input (1.8V–5.0V range); powers device core and defines RST output voltage level |
| 7 | PFI | Power-fail input; high-impedance node connected to external resistor divider for custom undervoltage detection |
| 8 | RSTIN | Unused in MAX6728 (dedicated to adjustable third monitor in MAX6723–MAX6727); connect to GND or VCC1 if left unconnected |
Key Features
| Feature | Design Value |
|---|---|
| Triple-voltage supervision | Simultaneous monitoring of VCC1 (4.625V), VCC2 (3.075V), and PFI (626.5mV ref) eliminates need for discrete supervisors |
| Power-fail interrupt generation | PFO output asserts within 2µs of PFI crossing threshold - enables fast software-triggered graceful shutdown |
| Guaranteed reset validity | Operates correctly down to VCC1 or VCC2 = 0.8V - ensures reset integrity during deep brownouts |
| Low-power design | 14µA typical supply current at 3.6V - extends battery life in portable telecom modules |
| No external components required | Internal 50kΩ MR pullup and precision bandgap references eliminate calibration resistors and trim pots |
Applications
| Telecom Power Management | Industrial PLC I/O Modules |
|---|---|
Use Scenario: Monitoring 48V DC-DC converter output, 3.3V logic rail, and backup battery voltage in remote radio units. IC Role / Device Role / Timing Role: Triple-supply supervisor asserting RST on main rail collapse and generating immediate PFO interrupt for battery switchover. Use Value: Prevents firmware corruption during AC loss by triggering controlled state save before backup power depletes. | Use Scenario: Supervising 24V field bus supply, 5V controller rail, and 3.3V FPGA core in modular I/O chassis. IC Role / Device Role / Timing Role: Detects undervoltage on any rail and holds processor reset for 210ms while isolating faulty module via PFO-linked watchdog timer. Use Value: Enables hot-swap-safe operation by ensuring clean power sequencing and preventing partial initialization. |
| Network Switch Line Cards | Medical Diagnostic Equipment |
Use Scenario: Validating 12V mid-rail, 3.3V PHY supply, and auxiliary 1.8V SerDes supply in high-port-density switches. IC Role / Device Role / Timing Role: Monitors all three rails independently; asserts RST only when critical combination fails, avoiding false resets. Use Value: Improves system uptime by distinguishing transient dips from true faults using 210ms timeout and 0.8V minimum operating voltage. | Use Scenario: Ensuring stable power to imaging sensor array, ADC reference, and ARM Cortex-M7 core in portable ultrasound devices. IC Role / Device Role / Timing Role: Uses PFI to monitor battery health and trigger PFO-driven interrupt for low-battery warning before shutdown. Use Value: Meets IEC 62304 safety requirements by guaranteeing deterministic reset behavior across full temperature range (-40°C to +85°C). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar triple-voltage supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6729KASDD3+ | Same thresholds, timing, and pinout; PFO is push-pull instead of open-drain | Requires no external pullup on PFO; better for driving heavy capacitive loads directly | Select MAX6729KASDD3+ when PFO must source current or interface with CMOS inputs without pullup |
| TPS3808G33DBVR | Dual-supply monitor (VDD, VDDQ); no PFI/PFO function; 3.3V fixed VDD threshold; 200ms timeout | Lacks third-voltage monitoring and power-fail interrupt capability - unsuitable for brownout warning use cases | Choose TPS3808G33DBVR only for cost-sensitive dual-rail systems where PFI functionality is omitted |
Compared with MAX6728KASDD3+, MAX6729KASDD3+ offers identical supervision but push-pull PFO for direct drive, while TPS3808G33DBVR reduces functionality to dual monitoring only - making MAX6728KASDD3+ the sole option supporting both triple-voltage detection and configurable power-fail alerting in one 8-pin package.
Availability
MAX6728KASDD3+ is available at Aetrix Electronics and suitable for telecom infrastructure, industrial control, and medical diagnostics requiring stable component supply, long-term lifecycle support, and guaranteed -40°C to +85°C operation.
Supply support for MAX6728KASDD3+ 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 supervision in miniature SOT23 packages - engineered specifically for space-constrained, multivoltage embedded systems needing reliable power sequencing and fail-safe reset behavior.
FAQ
What is the exact reset threshold voltage for VCC1 on the MAX6728KASDD3+?
The MAX6728KASDD3+ has a factory-trimmed VCC1 reset threshold of 4.625V (minimum 4.500V, maximum 4.750V) with ±0.5% hysteresis. This value is encoded in the "AS" suffix per Maxim's Reset Voltage Threshold Suffix Guide and applies across the full -40°C to +85°C operating range with 20ppm/°C tempco.
Does the MAX6728KASDD3+ support monitoring a third supply voltage beyond VCC1 and VCC2?
No - the MAX6728KASDD3+ monitors exactly three voltages: VCC1 (4.625V), VCC2 (3.075V), and PFI (via internal 626.5mV reference). Unlike MAX6723–MAX6727, it does not use RSTIN for adjustable third-supply monitoring; RSTIN is unused and must be tied to GND or VCC1 per datasheet guidance.
What is the function of the PFO pin on the MAX6728KASDD3+ and how does it differ from RST?
The PFO pin on MAX6728KASDD3+ is an active-low open-drain power-fail output that asserts immediately (2µs delay) when PFI drops below 626.5mV - with no timeout period. In contrast, RST is a push-pull active-low reset output held for 210ms after fault clearance. PFO enables fast interrupt-driven responses; RST ensures processor reset hold time.
Can the MAX6728KASDD3+ operate reliably when VCC1 drops below 1.0V?
Yes - the MAX6728KASDD3+ guarantees valid reset output logic states down to VCC1 = 0.8V or VCC2 = 0.8V. Its internal comparators and reset driver remain functional at this level, ensuring deterministic behavior during deep brownouts where many supervisors fail silently.
What package type and dimensions does the MAX6728KASDD3+ use?
The MAX6728KASDD3+ uses an 8-pin SOT23 package measuring 3.0mm × 1.6mm × 1.1mm (height), with standard lead pitch of 0.65mm. This compact footprint supports high-density PCB layouts and is compatible with standard reflow soldering profiles for automated manufacturing.
MAX6728KASDD3+ 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:
- -
MAX6728KASDD3+ FAQ
1.How can I place an order for MAX6728KASDD3+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6728KASDD3+ 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 MAX6728KASDD3+ reliable?
The price and inventory of MAX6728KASDD3+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6728KASDD3+ is usually 5 days.
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4.How is shipping managed for MAX6728KASDD3+?
MAX6728KASDD3+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6728KASDD3+ 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 MAX6728KASDD3+?
For technical support, including MAX6728KASDD3+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6728KASDD3+ requirements.
6.How does Aetrix verify that MAX6728KASDD3+ is sourced from the original manufacturer or authorized distributors?
All MAX6728KASDD3+ 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 MAX6728KASDD3+ meets industry standards.
7.What is the process for return or replacement of MAX6728KASDD3+?
All MAX6728KASDD3+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX6728KASDD3+, 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 MAX6728KASDD3+ part is unused and in its original packaging.
Return procedure for MAX6728KASDD3+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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