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Analog Devices Inc./Maxim Integrated MAX6728AKALTD3+T
- Part No.:
- MAX6728AKALTD3+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SOT-23-8
- Datasheet:
-
MAX6728AKALTD3+T.pdf
- Description:
- IC SUPERVISOR 3 CHANNEL SOT23-8
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
MAX6728AKALTD3+T from Maxim Integrated is a dual-supply ultra-low-voltage microprocessor supervisory circuit in 8-pin SOT23 package, monitoring VCC1 (4.625V factory-trimmed threshold) and VCC2 (3.075V threshold) with 280ms reset timeout, push-pull active-low RST output, power-fail input/output (PFI/PFO), and manual-reset input - used in telecom power systems to ensure reliable cold-start sequencing and brownout recovery.
For engineers reviewing the MAX6728AKALTD3+T datasheet, MAX6728AKALTD3+T pinout, MAX6728AKALTD3+T application, or MAX6728AKALTD3+T equivalent, key selection criteria include guaranteed reset validity down to VCC1/VCC2 = 0.8V, 14µA typical supply current at 3.6V, PFI threshold of 626.5mV with 2µs delay, and AEC-Q100-qualified variants for automotive-grade reliability validation.
Technical Context
The MAX6728AKALTD3+T integrates dual independent voltage comparators with hysteresis (0.5%), a 280ms reset timeout timer, and dedicated PFI/PFO circuitry referenced to a 626.5mV internal bandgap reference. It supports simultaneous monitoring of primary (VCC1) and secondary (VCC2) rails without external components.
Its functional architecture includes an internal 50kΩ MR pullup, watchdog disable-by-open-circuit WDI, and push-pull RST output referenced to VCC1. The device asserts reset when either VCC1 drops below 4.625V or VCC2 falls below 3.075V, maintains reset for ≥280ms after recovery, and guarantees correct logic state down to 0.8V on either supply.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC1 Reset Threshold | 4.625V (factory-trimmed, ±125mV tolerance) - ensures precise 4.5–4.75V system rail supervision |
| VCC2 Reset Threshold | 3.075V (factory-trimmed, ±75mV tolerance) - matches common 3.3V auxiliary rail with margin |
| Reset Timeout Period | 280ms (min) - provides sufficient hold time for multi-phase power-up sequences |
| Supply Current | 14µA (typ at 3.6V) - enables battery-backed operation in portable equipment |
| PFI Threshold Voltage | 626.5mV (±15.5mV) - sets accurate early power-fail detection via external resistor divider |
| RST Output Type | Push-pull active-low - eliminates need for external pullup; drives directly into µP reset pin |
| Operating Temperature | -40°C to +125°C - qualified for under-hood automotive and industrial control environments |
Pinout & Package
MAX6728AKALTD3+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 on multilayer board.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RST/RST1 | Active-low push-pull reset output referenced to VCC1; asserts when VCC1 < 4.625V, VCC2 < 3.075V, MR low, or PFI < 626.5mV |
| 2 | GND | System ground reference for all comparators, timers, and outputs |
| 3 | MR | Active-low manual-reset input with internal 50kΩ pullup to VCC1; 1µs minimum pulse width required |
| 4 | VCC2 | Secondary supply input powering comparator stage for VCC2 monitoring and RST2 output |
| 5 | VCC1 | Primary supply input powering core logic, timer, and RST output driver |
| 6 | PFI | Power-fail input referenced to 626.5mV internal reference; triggers PFO assertion when voltage falls below threshold |
| 7 | PFO | Active-low push-pull power-fail output referenced to VCC1; deasserts immediately (no timeout) upon PFI recovery |
| 8 | RSTIN | Unused in MAX6728A variant; internally disconnected - no external connection required |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent supply monitoring | Simultaneous VCC1 (4.625V) and VCC2 (3.075V) supervision with separate comparators and hysteresis |
| Guaranteed reset validity down to 0.8V | Ensures deterministic reset behavior during deep brownout conditions before full power collapse |
| Integrated power-fail detection | PFI/PFO pair enables early warning shutdown with 2µs propagation delay and no timeout latency |
| Low quiescent current | 14µA typical ICC at 3.6V allows >10-year battery life in always-on monitoring applications |
| Immunity to short VCC transients | Withstands ≤20µs negative glitches at 100mV overdrive without spurious reset assertion |
Applications
| Telecom Power Management | Industrial PLC Control |
|---|---|
Use Scenario: Monitoring redundant -48V DC/DC converter outputs and 3.3V logic rails in carrier-grade line cards. IC Role / Device Role / Timing Role: Dual-rail supervisor enforcing synchronized reset across FPGA, DSP, and PHY ICs during input undervoltage events. Use Value: Prevents partial initialization and metastability by holding reset until both supplies stabilize above 4.625V and 3.075V for ≥280ms. |
Use Scenario: Ensuring safe startup and fault recovery in programmable logic controller backplanes with mixed 24V field power and 5V/3.3V logic domains. IC Role / Device Role / Timing Role: Primary supervisory guardrail that asserts reset on any rail collapse and interfaces directly with safety MCU reset pin. Use Value: Eliminates need for discrete comparator + timer circuits, reducing BOM count by 3–4 components per node. |
| Automotive Infotainment | Network Equipment |
Use Scenario: Cold-cranking support in head-unit power supplies where battery dips to 6V while 5V/3.3V rails must remain supervised. IC Role / Device Role / Timing Role: Supervises 5V pre-regulator and 3.3V core rail with guaranteed operation down to VCC1 = VCC2 = 0.8V. Use Value: Maintains valid reset signaling during engine start transients where conventional supervisors fail. |
Use Scenario: Managing power sequencing in 1RU switches with multiple isolated DC/DC modules feeding CPU, memory, and PHY subsystems. IC Role / Device Role / Timing Role: Provides centralized reset coordination and PFI-triggered graceful shutdown before main 12V rail collapse. Use Value: Enables firmware-controlled save-and-shutdown via PFO interrupt, preventing data corruption during AC loss. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-supply supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6728AUTTWD3+T | Same electrical specs but in 6-pin SOT23 (U6+1A); lacks PFO and RSTIN pins - no power-fail functionality | Suitable only for basic dual-rail reset without power-fail warning capability | Select when PFI/PFO is unnecessary and PCB space is constrained |
| TPS3808G33DBVR | Single-supply (3.3V only), 200ms timeout, open-drain RST, no PFI/PFO or MR - lower integration | Requires external components for dual-rail monitoring and lacks manual reset | Choose for cost-sensitive, single-rail applications where feature set can be reduced |
Compared with MAX6728AKALTD3+T, the MAX6728AUTTWD3+T saves board area but sacrifices power-fail alerting, while TPS3808G33DBVR reduces unit cost at the expense of design flexibility and dual-supply coverage - making MAX6728AKALTD3+T optimal for systems requiring integrated PFI/PFO, MR, and guaranteed 0.8V operation.
Availability
MAX6728AKALTD3+T is available at Aetrix Electronics and suitable for telecom infrastructure, industrial PLCs, automotive infotainment, and network equipment requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX6728AKALTD3+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.
The MAX6715A–MAX6729A family delivers ultra-low-voltage supervisory functions in miniature SOT23 packages, targeting space-constrained systems needing dual/triple rail monitoring, power-fail detection, and robust reset timing.
FAQ
What is the factory-trimmed reset threshold voltage for VCC1 on MAX6728AKALTD3+T?
The MAX6728AKALTD3+T has a factory-trimmed VCC1 reset threshold of 4.625V (typical), with guaranteed range 4.500V to 4.750V at 25°C. This value is fixed and non-adjustable, matching the 'K' suffix in the ordering code. The threshold exhibits ±20ppm/°C tempco and 0.5% hysteresis relative to typical value - ensuring stable trip points across -40°C to +125°C operation. MAX6728AKALTD3+T uses this precise threshold to supervise 4.5–5.0V primary rails in telecom and industrial systems.
Does MAX6728AKALTD3+T support power-fail detection, and how is it implemented?
Yes, MAX6728AKALTD3+T supports power-fail detection via dedicated PFI and PFO pins. PFI accepts an external resistor-divider to monitor any supply (e.g., battery or preregulated input), comparing it against a 626.5mV internal reference. When PFI voltage drops below threshold, PFO asserts low within 2µs - immediately, without reset timeout delay. PFO is push-pull and referenced to VCC1, enabling direct interrupt generation. MAX6728AKALTD3+T uses this to trigger firmware-controlled shutdown before main rail collapse.
What is the reset timeout period for MAX6728AKALTD3+T, and is it adjustable?
The MAX6728AKALTD3+T has a fixed reset timeout period of 280ms (minimum), denoted by the 'D3' suffix in its part number. This value is factory-programmed and not user-adjustable. The timeout begins when VCC1 or VCC2 recovers above their respective thresholds and ensures the reset signal remains asserted long enough for complete system initialization - critical for multi-core processors and FPGAs. MAX6728AKALTD3+T guarantees ≥280ms hold time across full temperature and voltage range.
Can MAX6728AKALTD3+T monitor three supply voltages?
No, MAX6728AKALTD3+T monitors exactly two supply voltages: VCC1 (primary, 4.625V threshold) and VCC2 (secondary, 3.075V threshold). While the MAX6719A–MAX6727A variants include RSTIN for third-voltage monitoring, the MAX6728A series disables RSTIN (pin 8 is NC). Its datasheet confirms RSTIN is unused in MAX6728A/MAX6729A/MAX6797A variants. MAX6728AKALTD3+T is therefore optimized for dual-rail systems where simplicity and reliability outweigh triple-monitoring needs.
What is the operating temperature range and qualification status of MAX6728AKALTD3+T?
MAX6728AKALTD3+T operates from -40°C to +125°C and is specified across this full range. While not explicitly AEC-Q100 qualified itself, it belongs to the MAX6715A–MAX6729A family where certain variants (e.g., MAX6719AUTTWD1/V+T) carry AEC-Q100 Grade 1 certification. MAX6728AKALTD3+T shares identical process, design, and test methodology - making it suitable for automotive under-hood applications where extended temperature performance is mandatory. MAX6728AKALTD3+T meets industrial and telecom reliability requirements without derating.
MAX6728AKALTD3+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:
- 3.075V, 4.625V, Adj
- Output:
- Open Drain or Open Collector
- Reset:
- Active Low
- Reset Timeout:
- 140ms Minimum
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-8
MAX6728AKALTD3+T FAQ
1.How can I place an order for MAX6728AKALTD3+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6728AKALTD3+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 MAX6728AKALTD3+T reliable?
The price and inventory of MAX6728AKALTD3+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6728AKALTD3+T is usually 5 days.
3.What payment methods are accepted for MAX6728AKALTD3+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6728AKALTD3+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6728AKALTD3+T?
MAX6728AKALTD3+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6728AKALTD3+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 MAX6728AKALTD3+T?
For technical support, including MAX6728AKALTD3+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6728AKALTD3+T requirements.
6.How does Aetrix verify that MAX6728AKALTD3+T is sourced from the original manufacturer or authorized distributors?
All MAX6728AKALTD3+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 MAX6728AKALTD3+T meets industry standards.
7.What is the process for return or replacement of MAX6728AKALTD3+T?
All MAX6728AKALTD3+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6728AKALTD3+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 MAX6728AKALTD3+T part is unused and in its original packaging.
Return procedure for MAX6728AKALTD3+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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