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Analog Devices Inc./Maxim Integrated MAX6728AKASYD3+T
- Part No.:
- MAX6728AKASYD3+T
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SOT-23-8
- Datasheet:
-
MAX6728AKASYD3+T.pdf
- Description:
- IC SUPERVISOR 3 CHANNEL SOT23-8
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
The MAX6728AKASYD3+T from Maxim Integrated is a dual-supply ultra-low-voltage microprocessor supervisory circuit in an 8-pin SOT23 package, monitoring VCC1 (1.8V–5.0V) and VCC2 (0.9V–3.3V) with factory-trimmed reset thresholds, 140ms minimum reset timeout, power-fail input/output (PFI/PFO), and manual-reset (MR) capability. It ensures reliable system reset during brownout conditions in telecom and industrial embedded systems.
For engineers reviewing the MAX6728AKASYD3+T datasheet, MAX6728AKASYD3+T pinout, MAX6728AKASYD3+T application, or MAX6728AKASYD3+T equivalent, key selection criteria include dual-supply threshold accuracy (±1.5% over temperature), guaranteed reset validity down to VCC = 0.8V, PFI trip at 626.5mV ±15.5mV, and compatibility with 1.2V–5.5V supply rails.
Technical Context
The MAX6728AKASYD3+T integrates two independent voltage comparators for VCC1 and VCC2 supervision, a dedicated power-fail comparator (PFI → PFO), and a manual-reset input with internal 50kΩ pullup to VCC1. Its reset logic asserts active-low RST and PFO outputs when either supply falls below its trimmed threshold or PFI drops below 626.5mV.
It features a fixed 140ms (min) reset timeout period (suffix D3), push-pull RST and PFO outputs referenced to VCC1, and operates across –40°C to +125°C. The device guarantees valid reset output state as long as VCC1 ≥ 0.8V or VCC2 ≥ 0.8V - critical for low-voltage battery-backed systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC1 Threshold | 4.500V–4.750V (factory-trimmed, L-suffix; enables reliable 5V rail supervision) |
| VCC2 Threshold | 3.000V–3.150V (factory-trimmed, T-suffix; matches common 3.3V secondary rails) |
| PFI Threshold | 611mV–642mV (internal reference; supports precise external voltage monitoring via resistor divider) |
| Reset Timeout | 140ms min (D3 suffix; provides sufficient hold time for processor initialization) |
| Supply Current | 15µA typ at 3.6V (ultra-low quiescent current extends battery life in portable equipment) |
| Operating Temp | –40°C to +125°C (AEC-Q100-qualified grade for automotive and harsh industrial use) |
| Reset Output Type | Push-pull active-low RST and PFO (no external pullup required; drives directly into µP reset pins) |
Pinout & Package
MAX6728AKASYD3+T is housed in an 8-pin SOT23 package (package code K8SN+1, outline 21-0078), with thermal resistance θJA = 180°C/W on multilayer board.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - RST | Active-low reset output | Push-pull driver referenced to VCC1; asserts low on VCC1/VCC2 undervoltage or MR activation |
| 2 - GND | Ground reference | Common return for all internal comparators and output drivers; must be low-impedance |
| 3 - MR | Active-low manual-reset input | Internal 50kΩ pullup to VCC1; logic-low pulse ≥1µs forces reset for full timeout period |
| 4 - PFO | Active-low power-fail output | Push-pull output referenced to VCC1; deasserts immediately (no timeout) when PFI rises above threshold |
| 5 - VCC2 | Secondary supply input | Powers internal circuitry when > VCC1; monitored by dedicated comparator with 3.000V–3.150V threshold |
| 6 - VCC1 | Primary supply input | Main power rail input (1.8V–5.5V); powers device and sets reset threshold reference (4.500V–4.750V) |
| 7 - PFI | Power-fail monitor input | High-impedance comparator input (IIN ≤ ±100nA); triggers PFO when voltage falls below 626.5mV |
| 8 - NC | No connect | Unused pin; must remain floating per datasheet; no internal connection |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent supply monitoring | Simultaneous VCC1 (5V domain) and VCC2 (3.3V domain) supervision with separate thresholds and hysteresis |
| Power-fail detection with immediate response | PFI→PFO path delay <2µs; enables early warning shutdown before main supplies collapse |
| Guaranteed reset validity at ultra-low VCC | Outputs remain functional and logic-valid even when VCC1 or VCC2 drops to 0.8V |
| Immunity to short VCC transients | Rejects glitches <20µs wide at 100mV overdrive; prevents spurious resets in noisy environments |
| Low-power operation | 15µA typical supply current at 3.6V enables multi-year battery life in always-on monitoring applications |
Applications
| Telecom Power Management | Industrial PLC I/O Modules |
|---|---|
Use Scenario: Monitoring primary 48V-to-5V DC-DC converter output and isolated 3.3V FPGA core supply in base station line cards. IC Role / Device Role / Timing Role: Dual-supply supervisor asserting RST if either rail drops below spec, while PFO signals imminent AC loss to trigger graceful shutdown. Use Value: Prevents data corruption during brownout by holding µP in reset until both rails stabilize; PFO interrupt allows firmware to save state before backup capacitor depletion. | Use Scenario: Supervising 24V field bus input and 5V logic supply in DIN-rail mounted programmable logic controllers. IC Role / Device Role / Timing Role: Ensures deterministic boot sequence by enforcing 140ms reset hold time after cold start or voltage sag on either supply. Use Value: Eliminates need for discrete RC reset circuits; push-pull RST drives PLC µP directly without pullup resistors, reducing BOM count and layout area. |
| Automotive Infotainment Head Units | Medical Portable Diagnostic Devices |
Use Scenario: Validating 5V USB-C PD input and 1.2V SoC core supply in vehicle-mounted infotainment systems operating across –40°C to +105°C. IC Role / Device Role / Timing Role: AEC-Q100 qualified dual supervisor providing fail-safe reset during engine cranking-induced voltage dips. Use Value: Factory-trimmed thresholds ensure ±1.5% accuracy over temperature - critical for meeting ISO 16750-2 transient immunity requirements. | Use Scenario: Monitoring lithium-ion battery voltage (via PFI divider) and regulated 3.3V system rail in handheld ultrasound scanners. IC Role / Device Role / Timing Role: PFI detects battery drop to 3.2V; PFO triggers firmware-controlled shutdown before cutoff, preserving calibration data. Use Value: 626.5mV internal reference enables accurate low-voltage monitoring with high-value resistors (e.g., 1MΩ/200kΩ), minimizing battery drain. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-supply supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6729AKASYD3+T | Same pinout and electrical specs, but includes watchdog timer (WDI input); adds 35s startup + 1.12s normal timeout modes | Required where µP activity monitoring is needed alongside supply supervision | Select MAX6729AKASYD3+T only if watchdog functionality is mandatory; otherwise MAX6728AKASYD3+T reduces design complexity and cost |
| TPS3808G33DBVR | Single-supply (3.3V only), no PFI/PFO, no VCC2 monitoring; 200ms reset timeout; SOT23-6 package | Limited to single-rail systems; lacks auxiliary voltage monitoring and power-fail signaling | Use only in cost-sensitive, single-rail designs where dual-supply supervision and PFO are unnecessary |
Compared with MAX6729AKASYD3+T, the MAX6728AKASYD3+T omits watchdog circuitry - simplifying firmware integration and reducing susceptibility to false resets from WDI noise. Against TPS3808G33DBVR, it delivers true dual-rail supervision and integrated power-fail signaling in the same 8-pin footprint, enabling higher system reliability without adding discrete comparators.
Availability
MAX6728AKASYD3+T is available at Aetrix Electronics and suitable for telecom infrastructure, industrial PLCs, automotive infotainment, and medical portable devices requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX6728AKASYD3+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, multi-rail supervisory circuits optimized for space-constrained, high-reliability embedded systems requiring guaranteed reset behavior down to 0.8V supply.
FAQ
What is the exact reset timeout period of the MAX6728AKASYD3+T?
The MAX6728AKASYD3+T has a guaranteed minimum reset timeout period of 140ms, corresponding to the "D3" suffix in its part number. This value is factory-trimmed and specified over the full –40°C to +125°C operating temperature range, ensuring consistent reset hold time regardless of environmental conditions. The MAX6728AKASYD3+T does not include adjustable timeout options - the 140ms duration is fixed and production-tested.
Does the MAX6728AKASYD3+T support monitoring a third voltage rail?
No, the MAX6728AKASYD3+T does not support a third monitored voltage. Unlike variants such as MAX6723A–MAX6727A (which feature RSTIN input), the MAX6728AKASYD3+T is configured exclusively for dual-supply supervision (VCC1 and VCC2) and includes PFI/PFO for auxiliary power-fail detection - not adjustable undervoltage monitoring. For triple-rail supervision, select MAX6723AKASYD3+T or equivalent with RSTIN functionality.
What are the absolute maximum ratings for VCC1 and VCC2 on the MAX6728AKASYD3+T?
The MAX6728AKASYD3+T specifies absolute maximum ratings of –0.3V to +6V for both VCC1 and VCC2 terminals. However, functional operation is guaranteed only between 0.8V and 5.5V per supply. Exceeding 5.5V risks permanent damage, and operation below 0.8V invalidates reset output logic states. These limits are defined in the Absolute Maximum Ratings table of the official datasheet (Rev 6, 7/19).
Can the PFO output of the MAX6728AKASYD3+T drive a microcontroller interrupt pin directly?
Yes, the PFO output of the MAX6728AKASYD3+T is a push-pull active-low signal referenced to VCC1, capable of directly driving a µP interrupt pin without external pullup. With VOH ≥ 0.8 × VCC1 and VOL ≤ 0.3V at ISINK = 1.2mA, it meets standard CMOS input thresholds. Ensure the µP interrupt pin is configured for active-low edge-triggered or level-sensitive detection, and verify voltage compatibility - e.g., PFO driven from 3.3V VCC1 works reliably with 3.3V-tolerant µP inputs.
Is the MAX6728AKASYD3+T qualified for automotive applications?
The MAX6728AKASYD3+T is not individually AEC-Q100 qualified; however, it belongs to the MAX6715A–MAX6729A family, within which specific variants (e.g., MAX6719AUTTWD1/V+T) carry AEC-Q100 Grade 1 certification. The MAX6728AKASYD3+T shares identical process, design, and test methodology but lacks the formal qualification suffix. For production automotive use, confirm qualification status with Analog Devices' latest product change notices and consult the Automotive Product Selector Guide before final design-in.
MAX6728AKASYD3+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:
- 2.188V, 2.925V, 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
MAX6728AKASYD3+T FAQ
1.How can I place an order for MAX6728AKASYD3+T through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6728AKASYD3+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 MAX6728AKASYD3+T reliable?
The price and inventory of MAX6728AKASYD3+T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6728AKASYD3+T is usually 5 days.
3.What payment methods are accepted for MAX6728AKASYD3+T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6728AKASYD3+T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6728AKASYD3+T?
MAX6728AKASYD3+T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6728AKASYD3+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 MAX6728AKASYD3+T?
For technical support, including MAX6728AKASYD3+T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6728AKASYD3+T requirements.
6.How does Aetrix verify that MAX6728AKASYD3+T is sourced from the original manufacturer or authorized distributors?
All MAX6728AKASYD3+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 MAX6728AKASYD3+T meets industry standards.
7.What is the process for return or replacement of MAX6728AKASYD3+T?
All MAX6728AKASYD3+T units undergo pre-shipment inspection (PSI). If there is an issue with MAX6728AKASYD3+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 MAX6728AKASYD3+T part is unused and in its original packaging.
Return procedure for MAX6728AKASYD3+T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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