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Analog Devices Inc./Maxim Integrated MAX6728KALTD3+
- Part No.:
- MAX6728KALTD3+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SOT-23-8
- Datasheet:
-
MAX6728KALTD3+.pdf
- Description:
- IC SUPERVISOR MPU
- Quantity:
- Payment:
- Shipping:
Inventory:617
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Product details
Overview
MAX6728KALTD3+ from Maxim Integrated is a dual-voltage microprocessor supervisory IC monitoring VCC1 (primary) and VCC2 (secondary) supply rails with factory-trimmed reset thresholds of 4.625V (VTH1) and 3.075V (VTH2), 210ms minimum reset timeout, open-drain active-low RST output, power-fail input/output (PFI/PFO), and manual-reset input (MR). It operates from -40°C to +125°C in an 8-pin SOT23 package and is used in telecom power systems requiring reliable brownout detection and orderly shutdown.
For engineers reviewing the MAX6728KALTD3+ datasheet, MAX6728KALTD3+ pinout, MAX6728KALTD3+ application, or MAX6728KALTD3+ equivalent, key selection criteria include dual-supply threshold accuracy (±1.5% over temperature), guaranteed reset validity down to VCC1/VCC2 = 0.8V, low 15µA typical supply current at 3.6V, PFI threshold of 626.5mV with 3mV hysteresis, and compatibility with battery-backed industrial controllers.
Technical Context
The MAX6728KALTD3+ integrates two independent voltage comparators for VCC1 and VCC2, each with ±1.5% threshold tolerance over -40°C to +125°C and 20ppm/°C tempco. Its internal reset timer guarantees ≥210ms assertion after all monitored supplies recover above threshold.
It features a dedicated PFI comparator referenced to a 626.5mV internal bandgap, driving an open-drain PFO output with 2µs propagation delay; MR input includes a 50kΩ internal pullup to VCC1 and supports 1µs minimum pulse width with 100ns glitch rejection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC1 Reset Threshold | 4.625V (factory-trimmed, ±1.5% over temp) - ensures reliable reset assertion before 5V rail collapse affects CPU operation |
| VCC2 Reset Threshold | 3.075V (factory-trimmed, ±1.5% over temp) - matches common 3.3V I/O supply margin for safe deassertion |
| Reset Timeout Period | 210ms (min) - provides sufficient hold time for full processor initialization and peripheral stabilization |
| Supply Current | 15µA (typ at 3.6V) - enables use in always-on battery-powered subsystems without significant drain |
| PFI Threshold Voltage | 626.5mV (±15mV) - allows precise external resistor-divider setup for early power-fail warning on auxiliary rails |
| Operating Temperature | -40°C to +125°C - qualified for under-hood automotive and industrial control environments |
| Reset Output Type | Open-drain active-low RST - supports flexible pullup to any logic rail and wired-OR reset bus configurations |
Pinout & Package
MAX6728KALTD3+ uses an 8-pin SOT23 package (3.0mm × 1.6mm × 1.1mm body, 0.65mm pitch) with exposed pad for thermal performance in high-density PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - RST | Active-low reset output | Open-drain output asserted low during fault; requires external pullup; drives system reset line |
| 2 - GND | Ground reference | Common return for all internal comparators, timers, and I/O; must be low-impedance connection |
| 3 - MR | Manual-reset input | Active-low input with 50kΩ internal pullup to VCC1; initiates reset when pulled ≤0.3×VCC1 |
| 4 - VCC2 | Secondary supply input | Powers internal circuitry when VCC2 > VCC1; monitored for 3.075V undervoltage condition |
| 5 - VCC1 | Primary supply input | Main power source and primary monitor rail; powers device when VCC1 > VCC2; monitored for 4.625V undervoltage |
| 6 - PFI | Power-fail input | High-impedance comparator input (626.5mV threshold); used to monitor auxiliary supplies via resistor divider |
| 7 - PFO | Power-fail output | Open-drain active-low output asserted when PFI < 626.5mV; deasserts immediately without timeout |
| 8 - NC | No connect | Internally unused pin; must remain unconnected per datasheet to avoid functional interference |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent voltage monitoring | Simultaneous VCC1 (4.625V) and VCC2 (3.075V) supervision with separate comparators avoids single-point failure in multirail systems |
| Guaranteed reset validity down to 0.8V | Ensures correct RST logic state even during deep brownout-critical for fail-safe shutdown in automotive ECUs |
| Power-fail comparator with 2µs delay | Enables fast response to input rail collapse (e.g., battery sag), triggering PFO before system data corruption occurs |
| MR input with 100ns glitch rejection | Rejects EMI-induced noise on reset button lines, preventing spurious resets in electrically noisy industrial enclosures |
| Low 15µA supply current | Extends battery life in always-on telemetry modules where supervisor draws current continuously |
Applications
| Telecom Power Management | Industrial PLC I/O Modules |
|---|---|
Use Scenario: Monitoring 48V DC-DC converter output and 3.3V FPGA I/O rail in remote radio units. IC Role / Device Role / Timing Role: Dual-supply supervisor asserting RST on either rail collapse and generating PFO interrupt for graceful baseband processor shutdown. Use Value: Prevents firmware corruption during transient AC grid dips by holding reset until both rails stabilize for ≥210ms. | Use Scenario: Supervising 24V fieldbus supply and 5V logic rail in DIN-rail mounted programmable logic controllers. IC Role / Device Role / Timing Role: Primary/secondary voltage monitor with MR input for field technician-initiated reset and PFI for backup battery health check. Use Value: Enables deterministic restart after brownout without requiring external RC timing networks or discrete comparators. |
| Automotive Body Control Module | Medical Infusion Pump Power System |
Use Scenario: Validating 12V battery-derived main supply and 3.3V microcontroller core rail in under-hood BCMs. IC Role / Device Role / Timing Role: AEC-Q100-compliant dual-supply supervisor with reset timeout aligned to CAN bus wake-up sequence timing. Use Value: Guarantees reset remains asserted through cold-crank voltage dip (down to 6V) and recovers only after stable 12V/3.3V for ≥210ms. | Use Scenario: Monitoring main 24V DC supply and isolated 5V analog front-end rail in battery-operated infusion pumps. IC Role / Device Role / Timing Role: Dual-rail supervisor with PFI used to detect falling battery voltage and trigger alarm before critical shutdown. Use Value: Provides 626.5mV precision PFI threshold enabling accurate end-of-battery-life prediction within ±3% voltage error. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-supply supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6729KALTD3+ | Same pinout, identical VTH1/VTH2 thresholds and timeout, but adds watchdog input (WDI) capability | Required where software hang detection is needed alongside power monitoring | Select MAX6729KALTD3+ only if WDI functionality is implemented; otherwise MAX6728KALTD3+ reduces BOM count and layout complexity |
| TPS3808G33DBVR | Single-supply (3.3V only), no PFI/PFO, 200ms timeout, push-pull RST output | Limited to 3.3V-only systems without auxiliary rail monitoring or power-fail signaling | Use TPS3808G33DBVR only in cost-sensitive 3.3V-only designs lacking PFI requirements; MAX6728KALTD3+ supports dual-rail + PFI in same footprint |
Compared with MAX6729KALTD3+, MAX6728KALTD3+ removes WDI to reduce pin count and simplify firmware integration; compared with TPS3808G33DBVR, it adds VCC2 monitoring, PFI/PFO, and open-drain flexibility-making it suitable for complex multivoltage industrial systems where reliability trumps minimalism.
Availability
MAX6728KALTD3+ is available at Aetrix Electronics and suitable for telecom infrastructure, industrial PLCs, and automotive body control modules requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX6728KALTD3+ 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 demanding industrial, automotive, and communications applications.
The MAX6715A–MAX6729A family delivers ultra-low-voltage, multirail supervisory circuits optimized for space-constrained systems needing guaranteed reset behavior down to 0.8V and robust noise immunity in harsh environments.
FAQ
What is the exact reset threshold voltage for VCC1 and VCC2 on the MAX6728KALTD3+?
The MAX6728KALTD3+ has factory-trimmed reset thresholds of 4.625V (VTH1) for VCC1 and 3.075V (VTH2) for VCC2, with ±1.5% tolerance over -40°C to +125°C and 20ppm/°C tempco. These values are fixed by the "KA" suffix per Maxim's Reset Voltage Threshold Suffix Guide and do not require external configuration. The MAX6728KALTD3+ uses these precise thresholds to ensure deterministic reset timing in 5V/3.3V dual-rail systems.
Does the MAX6728KALTD3+ support power-fail detection on a third supply rail?
No, the MAX6728KALTD3+ does not support a third monitored rail via RSTIN. Unlike MAX6723A–MAX6727A variants, MAX6728KALTD3+ omits the RSTIN pin (pin 5 is VCC1, pin 6 is PFI). Its PFI input is dedicated to power-fail monitoring only and cannot be repurposed as a third voltage supervisor. For triple-rail monitoring, consider MAX6723KALTD3+ instead. The MAX6728KALTD3+ focuses on dual-supply supervision plus PFI/PFO functionality.
What is the function of the NC pin on the MAX6728KALTD3+?
Pin 8 on the MAX6728KALTD3+ is designated NC (No Connect) and is internally unused. Per Maxim's datasheet, this pin must remain unconnected on the PCB to prevent unintended coupling or functional disruption. It is not tied to ground, VCC, or any internal node. Leaving it floating is acceptable, but soldering or routing to other nets may compromise device reliability. All functional signals for the MAX6728KALTD3+ are confined to pins 1–7.
Can the MAX6728KALTD3+ operate with VCC1 and VCC2 supplied from different voltage sources?
Yes, the MAX6728KALTD3+ is explicitly designed to monitor independent VCC1 and VCC2 supplies-for example, a 5V DC-DC output and a separate 3.3V LDO. The device powers itself from whichever supply is higher (VCC1 or VCC2), while independently comparing each against its factory-set threshold. This architecture allows true dual-rail supervision in systems where supplies ramp at different rates or originate from disparate regulators. The MAX6728KALTD3+ guarantees valid reset output as long as either VCC1 or VCC2 remains ≥0.8V.
Is the MAX6728KALTD3+ RoHS-compliant and lead-free?
Yes, the "+" suffix in MAX6728KALTD3+ indicates a lead(Pb)-free and RoHS-compliant package per Maxim Integrated's ordering nomenclature. The device uses matte-tin plating on its 8-pin SOT23 terminals and meets JEDEC J-STD-020 moisture sensitivity level 1 (MSL-1) requirements. No lead-based solder or finishes are used in the MAX6728KALTD3+ manufacturing process, making it suitable for environmentally regulated industrial and medical applications.
MAX6728KALTD3+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SOT-23-8
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Power Supply Monitor
- Number of Voltages Monitored:
- 2
- Voltage - Threshold:
- 3.075V, 4.625V, Adj
- Output:
- Open Drain or Open Collector
- Reset:
- Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-8
MAX6728KALTD3+ FAQ
1.How can I place an order for MAX6728KALTD3+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6728KALTD3+ 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 MAX6728KALTD3+ reliable?
The price and inventory of MAX6728KALTD3+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6728KALTD3+ is usually 5 days.
3.What payment methods are accepted for MAX6728KALTD3+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6728KALTD3+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6728KALTD3+?
MAX6728KALTD3+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6728KALTD3+ 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 MAX6728KALTD3+?
For technical support, including MAX6728KALTD3+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6728KALTD3+ requirements.
6.How does Aetrix verify that MAX6728KALTD3+ is sourced from the original manufacturer or authorized distributors?
All MAX6728KALTD3+ 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 MAX6728KALTD3+ meets industry standards.
7.What is the process for return or replacement of MAX6728KALTD3+?
All MAX6728KALTD3+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX6728KALTD3+, 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 MAX6728KALTD3+ part is unused and in its original packaging.
Return procedure for MAX6728KALTD3+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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