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Analog Devices Inc./Maxim Integrated MAX6728KAZWD3+
- Part No.:
- MAX6728KAZWD3+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- -
- Datasheet:
-
MAX6728KAZWD3+.pdf
- Description:
- IC SUPERVISOR
- Quantity:
- Payment:
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Product details
Overview
MAX6728KAZWD3+ from Maxim Integrated is a triple-voltage microprocessor supervisory circuit in an 8-pin SOT23 package, monitoring VCC1 (1.62V threshold), VCC2 (0.788V threshold), and PFI (626.5mV internal reference) with push-pull RST and open-drain PFO outputs, 210ms reset timeout, and watchdog timer support - used in telecom power management to ensure reliable boot and brownout recovery.
For engineers reviewing the MAX6728KAZWD3+ datasheet, MAX6728KAZWD3+ pinout, MAX6728KAZWD3+ application, or MAX6728KAZWD3+ equivalent, this page delivers verified electrical specs, exact pin functions, dual-supply reset behavior, power-fail comparator timing, and validated alternative parts for multivoltage system design.
Technical Context
The MAX6728KAZWD3+ integrates three independent voltage monitors: primary supply (VCC1) with factory-trimmed 1.62V reset threshold, secondary supply (VCC2) at 0.788V, and power-fail input (PFI) referenced to a 626.5mV internal bandgap. It asserts active-low RST (push-pull) and PFO (open-drain) when any monitored voltage falls below its threshold.
It features a 210ms minimum reset timeout (D3 suffix), manual reset input (MR) with 50kΩ internal pullup, and power-fail detection with 2µs propagation delay from PFI to PFO. The device guarantees valid reset output down to VCC1 or VCC2 = 0.8V and draws only 14µA typical supply current at 3.6V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC1 Reset Threshold | 1.62V (typ), factory-trimmed - ensures precise reset assertion during 1.8V rail brownout |
| VCC2 Reset Threshold | 0.788V (typ), factory-trimmed - supports reliable monitoring of sub-1V core supplies |
| PFI Threshold Voltage | 626.5mV (typ), internal reference - enables accurate external power-fail detection via resistor divider |
| Reset Timeout Period | 210ms (min), D3 suffix - provides sufficient hold time for processor initialization sequences |
| Supply Current | 14µA (typ) at 3.6V - minimizes quiescent load in battery-backed or low-power systems |
| Operating Temperature | -40°C to +85°C - qualified for industrial and telecom equipment environments |
| Package | 8-pin SOT23 - compact footprint compatible with high-density PCB layouts |
Pinout & Package
MAX6728KAZWD3+ uses an 8-pin SOT23 package (KA suffix), with pins arranged in standard SOT23-8 configuration: GND on Pin 1, VCC2 on Pin 2, MR on Pin 3, VCC1 on Pin 4, PFO on Pin 5, RST on Pin 6, PFI on Pin 7, and NC on Pin 8.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | GND | Ground reference for all internal comparators and output drivers |
| 2 | VCC2 | Secondary supply input powering VCC2 monitor and RST2 logic (not used in MAX6728) |
| 3 | MR | Active-low manual reset input with 50kΩ internal pullup to VCC1 - initiates reset on logic-low pulse ≥1µs |
| 4 | VCC1 | Primary supply input powering device core, VCC1 monitor, and push-pull RST driver |
| 5 | PFO | Active-low power-fail output (open-drain) - asserts when PFI < 626.5mV, no timeout delay |
| 6 | RST | Active-low reset output (push-pull) - asserted during VCC1/VCC2/PFI undervoltage or MR low, held for 210ms |
| 7 | PFI | Power-fail input (high-impedance) - connected to resistor divider to set external trip point relative to 626.5mV reference |
| 8 | NC | No connect - internally unconnected, must be left floating or tied to GND per layout guidelines |
Key Features
| Feature | Design Value |
|---|---|
| Triple-voltage supervision | Simultaneous monitoring of VCC1 (1.62V), VCC2 (0.788V), and PFI (626.5mV) enables full-system power integrity coverage |
| Push-pull RST + open-drain PFO | Dual-output architecture allows direct µP reset assertion and independent power-fail interrupt signaling without external pullups |
| Guaranteed reset validity down to 0.8V | Ensures deterministic reset state even during deep brownout conditions on either supply rail |
| 2µs PFI-to-PFO propagation delay | Enables fast power-fail response for orderly software shutdown before critical voltage collapse |
| 210ms reset timeout (D3) | Matches typical bootloader execution windows in embedded telecom processors |
Applications
| Telecom Power Sequencing | Industrial PLC I/O Module |
|---|---|
|
Use Scenario: Monitoring 3.3V, 1.2V, and backup battery rails in LTE baseband power management. IC Role / Device Role / Timing Role: Triple-supply supervisor asserting RST during VCC1 brownout and PFO during battery sag to trigger firmware save. Use Value: Prevents corrupted configuration writes by synchronizing reset and power-fail interrupts with 210ms hold time and 2µs PFO latency. |
Use Scenario: Ensuring safe startup/shutdown of analog I/O channels powered by isolated DC/DC converters. IC Role / Device Role / Timing Role: Supervising primary 24V-derived 5V rail, isolated 3.3V logic rail, and PFI-connected auxiliary 12V supply. Use Value: Guarantees µP reset remains asserted until all rails stabilize above thresholds, eliminating spurious I/O activation. |
| Network Switch ASIC Boot | Medical Diagnostic Imaging PSU |
|
Use Scenario: Validating 1.8V core, 3.3V I/O, and 12V bias supplies before releasing ASIC reset in 10G Ethernet switch line cards. IC Role / Device Role / Timing Role: Dual-rail supervisor with PFI used to monitor pre-regulated 12V - triggers PFO interrupt for early warning prior to main rail failure. Use Value: Enables firmware-controlled graceful traffic failover using PFO edge detection, while RST enforces hard reset if thresholds violated. |
Use Scenario: Monitoring high-precision ±15V and +5V analog supplies feeding CT scanner detector front-ends. IC Role / Device Role / Timing Role: Using PFI to detect negative rail collapse via inverted resistor network; RST holds FPGA in reset until all rails settle. Use Value: Eliminates image artifacts by preventing data acquisition during unstable supply conditions, leveraging guaranteed 0.8V reset validity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar triple-voltage supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6729KAZWD3+ | Push-pull PFO output (vs. open-drain in MAX6728); identical VCC1/VCC2/PFI thresholds and 210ms timeout | Requires no external PFO pullup; better suited for driving CMOS inputs directly | Select MAX6729KAZWD3+ when PFO must drive logic without external components; otherwise MAX6728KAZWD3+ offers lower BOM count with open-drain flexibility |
| TPS3808G33DBVR | Dual-supply monitor only (no PFI); 3.3V fixed VDD threshold; 200ms timeout; SOT23-6 package | Lacks third-monitor capability and power-fail interrupt; suitable only for simpler two-rail systems | Choose TPS3808G33DBVR for cost-sensitive dual-rail designs where PFI functionality is unnecessary and board space is constrained |
Compared with MAX6728KAZWD3+, MAX6729KAZWD3+ eliminates need for PFO pullup resistor but shares identical supervision accuracy and timing; TPS3808G33DBVR reduces feature set and package size but cannot replace triple-monitoring requirements.
Availability
MAX6728KAZWD3+ is available at Aetrix Electronics and suitable for telecom infrastructure, industrial PLCs, and medical imaging equipment requiring stable component supply, long-lifecycle assurance, and guaranteed -40°C to +85°C operation.
Supply support for MAX6728KAZWD3+ 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 power, sensing, and interface applications, with leadership in supervisory, PMIC, and data-converter technologies.
The MAX6715–MAX6729 family was engineered specifically for multivoltage embedded systems needing compact, ultra-low-current supervision with configurable reset timing and auxiliary monitoring inputs like PFI.
FAQ
What is the exact reset threshold voltage for VCC1 on the MAX6728KAZWD3+?
The MAX6728KAZWD3+ has a factory-trimmed VCC1 reset threshold of 1.62V (typical), with min/max values of 1.575V and 1.665V across temperature and process variation. This value is encoded in the 'Z' suffix per Maxim's Reset Voltage Threshold Suffix Guide and applies specifically to the MAX6728KAZWD3+ variant.
Does the MAX6728KAZWD3+ support monitoring a negative supply voltage?
Yes - the MAX6728KAZWD3+ can monitor negative supplies using the PFI input with an appropriate resistor-divider network as shown in Figure 3b of the datasheet. When the negative rail drops, PFI falls below 626.5mV and PFO asserts, enabling early warning or controlled shutdown.
What is the function of Pin 8 (NC) on the MAX6728KAZWD3+?
Pin 8 on the MAX6728KAZWD3+ is a no-connect terminal - it is internally unconnected and must be left floating or tied to GND per Maxim's layout recommendations to avoid parasitic coupling. It is not used for reset, watchdog, or power-fail functions in this variant.
How does the watchdog timer behave after power-up on the MAX6728KAZWD3+?
The MAX6728KAZWD3+ implements a dual-mode watchdog: after power-up or reset, it enters a 35s minimum startup period before transitioning to the normal 1.12s timeout mode. This allows complex boot sequences to complete before watchdog enforcement begins.
Can the MAX6728KAZWD3+ operate with VCC1 = 1.5V?
No - the MAX6728KAZWD3+ requires VCC1 ≥ 1.62V to guarantee proper reset assertion, and its absolute minimum operating voltage is 0.8V only for maintaining valid reset logic state (not full functionality). At 1.5V, VCC1 is below the 1.575V minimum threshold, so reset will be asserted continuously.
MAX6728KAZWD3+ 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:
- -
MAX6728KAZWD3+ FAQ
1.How can I place an order for MAX6728KAZWD3+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6728KAZWD3+ 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 MAX6728KAZWD3+ reliable?
The price and inventory of MAX6728KAZWD3+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6728KAZWD3+ is usually 5 days.
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Once your MAX6728KAZWD3+ 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 MAX6728KAZWD3+?
For technical support, including MAX6728KAZWD3+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6728KAZWD3+ requirements.
6.How does Aetrix verify that MAX6728KAZWD3+ is sourced from the original manufacturer or authorized distributors?
All MAX6728KAZWD3+ 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 MAX6728KAZWD3+ meets industry standards.
7.What is the process for return or replacement of MAX6728KAZWD3+?
All MAX6728KAZWD3+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX6728KAZWD3+, 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 MAX6728KAZWD3+ part is unused and in its original packaging.
Return procedure for MAX6728KAZWD3+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MAX6728KAZWD3+ Tags
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MIC826SYMT-TR
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