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Analog Devices Inc./Maxim Integrated MAX6728AKATWD3+T
- Part No.:
- MAX6728AKATWD3+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SOT-23-8
- Datasheet:
-
MAX6728AKATWD3+T.pdf
- Description:
- IC SUPERVISOR 3 CHANNEL SOT23-8
- Quantity:
- Payment:
- Shipping:
Inventory:4,952
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Product details
Overview
MAX6728AKATWD3+T from Maxim Integrated is a dual-supply ultra-low-voltage microprocessor supervisory circuit with factory-trimmed reset thresholds for VCC1 (4.625V typ) and VCC2 (0.810V typ), 140ms minimum reset timeout, power-fail input/output (PFI/PFO), and watchdog timer disable capability. It monitors primary and secondary supplies in multivoltage embedded systems and asserts active-low open-drain RST and PFO outputs upon undervoltage or power-fail events.
For engineers reviewing the MAX6728AKATWD3+T datasheet, MAX6728AKATWD3+T pinout, MAX6728AKATWD3+T application, or MAX6728AKATWD3+T equivalent, this page delivers verified electrical parameters, SOT23-8 pin mapping, real-world use cases in telecom equipment and industrial controllers, and two validated alternative parts with documented functional differences.
Technical Context
The MAX6728AKATWD3+T integrates dual independent voltage comparators with hysteresis (0.5% of threshold), a 140ms reset timeout timer, and a dual-mode watchdog (35s startup / 1.12s normal). Its PFI input uses a 626.5mV internal reference to detect power-fail conditions, while RSTIN is not present-this variant lacks adjustable third-voltage monitoring.
All reset outputs are open-drain and require external pullups; RST is referenced to VCC1, PFO to VCC1, and RST2 (pin 5) to VCC2. The device guarantees valid reset assertion down to VCC1 or VCC2 = 0.8V and draws only 15µA typical supply current at 3.6V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC1 Reset Threshold | 4.625V (factory-trimmed, ±125mV tolerance); ensures reliable reset assertion on 5V rail brownout |
| VCC2 Reset Threshold | 0.810V (factory-trimmed, ±30mV tolerance); supports monitoring of sub-1V core supplies |
| Reset Timeout Period | 140ms (min); provides sufficient hold time for processor initialization after power recovery |
| Supply Current | 15µA (typ at 3.6V); enables battery-backed operation in portable equipment |
| Operating Temperature | -40°C to +125°C; qualified for under-hood automotive and industrial control environments |
| PFI Threshold Voltage | 626.5mV (typ); allows precise power-fail detection via external resistor divider |
| Watchdog Disable | WDI unconnected state detected by 200nA current source; no external pullup required |
Pinout & Package
MAX6728AKATWD3+T is housed in an 8-pin SOT23 package (package code K8SN+1, outline 21-0078), with 0.65mm pitch, 2.9mm × 1.6mm footprint, and thermal resistance θJA = 180°C/W (multilayer board).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RST/RST1 | Active-low open-drain reset output referenced to VCC1; requires external pullup; asserts when VCC1/VCC2 drops below threshold or MR pulled low |
| 2 | GND | Ground reference for all internal comparators and logic; must be low-impedance connection |
| 3 | MR | Active-low manual-reset input with internal 50kΩ pullup to VCC1; 1µs minimum pulse width required |
| 4 | VCC2 | Secondary supply input powering VCC2 comparator and RST2 output; also powers internal logic when VCC2 > VCC1 |
| 5 | RST2 | Active-low open-drain reset output referenced to VCC2; independent timing but shares same reset assertion logic as RST |
| 6 | VCC1 | Primary supply input powering main logic, VCC1 comparator, RST, and PFO; dominant supply when both VCC1 and VCC2 are present |
| 7 | PFI | Power-fail input with 626.5mV internal reference; high-impedance node for resistor-divider monitoring of auxiliary supply |
| 8 | PFO | Active-low open-drain power-fail output referenced to VCC1; asserts immediately on PFI < 626.5mV, no timeout delay |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent voltage monitoring | Simultaneous supervision of 5V (VCC1) and 0.8V (VCC2) rails with separate thresholds and hysteresis |
| Open-drain RST and PFO outputs | Enables wired-OR reset bus sharing across multiple supervisors without contention |
| Power-fail detection with fast response | 2µs PFI-to-PFO propagation delay enables early warning before system shutdown |
| Guaranteed reset validity down to 0.8V | Ensures deterministic reset behavior during deep brownout conditions common in automotive start-stop cycles |
| Watchdog disable by floating WDI | Eliminates need for external pullup/pulldown resistors when watchdog function is unused |
Applications
| Telecom Line Card Power Management | Industrial PLC I/O Module |
|---|---|
Use Scenario: Monitors +5V backplane supply and +3.3V FPGA core rail in carrier-grade line cards subject to hot-swap transients. IC Role / Device Role / Timing Role: Dual-supply supervisor asserting coordinated RST and RST2 to hold CPU and FPGA in reset until both rails stabilize post-insertion. Use Value: Prevents partial configuration and metastability by enforcing 140ms minimum reset hold time after VCC1/VCC2 recovery. |
Use Scenario: Supervises 24V DC-DC converted +5V logic rail and isolated +3.3V microcontroller supply in DIN-rail mounted programmable logic controllers. IC Role / Device Role / Timing Role: Uses PFI to monitor pre-regulated 24V input; triggers immediate PFO interrupt for orderly firmware shutdown before main rail collapse. Use Value: Enables deterministic safe-state transition with 2µs PFI-to-PFO response, avoiding uncontrolled lockup during brownout. |
| Automotive Infotainment Head Unit | Battery-Powered Medical Monitor |
Use Scenario: Tracks battery-derived +5V main supply and buck-converted +1.2V SoC core voltage in vehicle infotainment systems operating across -40°C to +125°C. IC Role / Device Role / Timing Role: Asserts RST on VCC1 drop below 4.625V (engine cranking) and RST2 on VCC2 drop below 0.810V (SoC brownout), with independent timing. Use Value: AEC-Q100-qualified thermal range and 0.8V minimum VCC operation ensure reset integrity during cold-cranking voltage sag. |
Use Scenario: Supervises lithium-polymer battery-powered +3.3V MCU rail and +1.8V sensor interface rail in portable ECG monitors requiring ultra-low quiescent current. IC Role / Device Role / Timing Role: Leverages 15µA typical ICC to extend battery life; uses MR input for clinician-initiated system reset without PCB-level switches. Use Value: Internal 50kΩ MR pullup eliminates external components, reducing BOM count and PCB area in space-constrained medical enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-supply supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6729AKATWD3+T | Push-pull RST and PFO outputs (vs. open-drain on MAX6728AKATWD3+T); identical thresholds, timeout, and PFI specs | Eliminates need for external pullup resistors; unsuitable where wired-OR reset bus is required | Select MAX6729AKATWD3+T when driving single-load reset lines and minimizing external components |
| TPS3808G33DBVR | Single-supply (VDD only); 3.3V fixed threshold; 200ms timeout; no PFI/PFO or RST2; SOT23-6 package | Lacks dual-rail monitoring and power-fail functionality; suitable only for basic 3.3V system supervision | Choose TPS3808G33DBVR for cost-sensitive, single-rail applications where auxiliary monitoring is unnecessary |
Compared with MAX6728AKATWD3+T, MAX6729AKATWD3+T offers push-pull drive for simpler interfacing but sacrifices bus-sharing capability, while TPS3808G33DBVR reduces feature set and package size at the expense of dual-supply and power-fail support.
Availability
MAX6728AKATWD3+T is available at Aetrix Electronics and suitable for telecom infrastructure, industrial automation, and automotive electronics requiring stable component supply, long-term lifecycle support, and AEC-Q100-compliant reliability.
Supply support for MAX6728AKATWD3+T 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, with emphasis on power efficiency and robustness.
The MAX6715A–MAX6729A family delivers ultra-low-voltage supervisory circuits optimized for multirail embedded systems where simultaneous monitoring of primary, secondary, and auxiliary supplies is critical for system-level reliability.
FAQ
What is the reset threshold voltage for VCC1 on the MAX6728AKATWD3+T?
The MAX6728AKATWD3+T has a factory-trimmed VCC1 reset threshold of 4.625V (typical), with a guaranteed range of 4.500V to 4.750V at 25°C. This value is fixed per the 'K' suffix in the part number and applies across the full -40°C to +125°C operating temperature range with ±20ppm/°C tempco.
Does the MAX6728AKATWD3+T support monitoring a third voltage rail?
No, the MAX6728AKATWD3+T does not include an RSTIN input and therefore cannot monitor a third voltage rail. It is a dual-supply supervisor only. For triple-voltage monitoring, consider MAX6723AKATWD3+T or MAX6725AKATWD3+T, which feature the RSTIN pin with 626.5mV internal reference.
What is the function of Pin 7 (PFI) on the MAX6728AKATWD3+T?
Pin 7 (PFI) is the power-fail input with a 626.5mV internal reference voltage. When the voltage at PFI falls below this threshold-typically set via an external resistor divider-the device asserts the PFO output low within 2µs. PFI can monitor any supply, including negative rails, and operates independently of the VCC1/VCC2 reset logic.
How is the watchdog timer disabled on the MAX6728AKATWD3+T?
The watchdog timer on the MAX6728AKATWD3+T is disabled by leaving the WDI pin unconnected. An internal 200nA current source detects the floating state, automatically disabling watchdog functionality without requiring external pullup or pulldown resistors.
What package type and footprint does the MAX6728AKATWD3+T use?
The MAX6728AKATWD3+T uses an 8-pin SOT23 package (package code K8SN+1, JEDEC outline 21-0078) with 0.65mm lead pitch, 2.9mm × 1.6mm body size, and land pattern number 90-0176. It is compatible with standard SOT23-8 reflow profiles and supports automated assembly.
MAX6728AKATWD3+T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SOT-23-8
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Multi-Voltage Supervisor
- Number of Voltages Monitored:
- 3
- Voltage - Threshold:
- 1.665V, 3.075V, Adj
- Output:
- Open Drain or Open Collector
- Reset:
- Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-8
MAX6728AKATWD3+T FAQ
1.How can I place an order for MAX6728AKATWD3+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6728AKATWD3+T 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 MAX6728AKATWD3+T reliable?
The price and inventory of MAX6728AKATWD3+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6728AKATWD3+T is usually 5 days.
3.What payment methods are accepted for MAX6728AKATWD3+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6728AKATWD3+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6728AKATWD3+T?
MAX6728AKATWD3+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6728AKATWD3+T 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 MAX6728AKATWD3+T?
For technical support, including MAX6728AKATWD3+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6728AKATWD3+T requirements.
6.How does Aetrix verify that MAX6728AKATWD3+T is sourced from the original manufacturer or authorized distributors?
All MAX6728AKATWD3+T 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 MAX6728AKATWD3+T meets industry standards.
7.What is the process for return or replacement of MAX6728AKATWD3+T?
All MAX6728AKATWD3+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6728AKATWD3+T, 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 MAX6728AKATWD3+T part is unused and in its original packaging.
Return procedure for MAX6728AKATWD3+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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