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Analog Devices Inc./Maxim Integrated MAX6729KAYDD3+
- Part No.:
- MAX6729KAYDD3+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SOT-23-8
- Datasheet:
-
MAX6729KAYDD3+.pdf
- Description:
- IC SUPERVISOR 3 CHANNEL SOT23-8
- Quantity:
- Payment:
- Shipping:
Inventory:1,232
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Product details
Overview
MAX6729KAYDD3+ from Maxim Integrated is a triple-voltage microprocessor supervisory circuit in an 8-pin SOT23 package, monitoring VCC1 (primary), VCC2 (secondary), and an externally adjustable RSTIN input down to 0.626V. It provides push-pull active-low reset output (RST), manual reset (MR), watchdog timer (WDI), and power-fail input/output (PFI/PFO) with 210ms minimum reset timeout. It ensures reliable system boot and brownout recovery in battery-powered telecom and industrial controllers.
For engineers reviewing the MAX6729KAYDD3+ datasheet, MAX6729KAYDD3+ pinout, MAX6729KAYDD3+ application, or MAX6729KAYDD3+ equivalent, this page delivers verified electrical specs, exact pin functions, real-world use cases for multivoltage systems, and two confirmed alternative parts with documented functional differences - all validated against Maxim's official datasheet Rev 5 (12/2005).
Technical Context
The MAX6729KAYDD3+ integrates three independent voltage monitors: factory-trimmed thresholds on VCC1 (1.8V–5.0V range) and VCC2 (0.9V–3.3V range), plus an adjustable RSTIN comparator referenced to a 626.5mV internal bandgap. Its dual-mode watchdog features a 35s startup period followed by a 1.12s normal timeout, triggered by WDI edge transitions.
It supports push-pull RST output referenced to VCC1, open-drain PFO referenced to VCC1, and includes MR with 50kΩ internal pullup. Reset assertion is guaranteed valid down to VCC1 or VCC2 = 0.8V, and immunity to sub-20µs VCC transients is confirmed per typical operating characteristics.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC1 Threshold | 4.625V (typ), factory-trimmed - sets primary supply brownout detection point for 5V logic rails |
| VCC2 Threshold | 3.075V (typ), factory-trimmed - enables precise monitoring of 3.3V I/O or auxiliary supplies |
| RSTIN Threshold | 626.5mV (typ), internal reference - allows external resistor-divider to monitor third supply as low as 0.62V |
| Reset Timeout | 210ms (min), D3 suffix - ensures µP reset hold time meets boot sequence timing requirements |
| Supply Current | 14µA (typ) at 3.6V - enables ultra-low-power operation in battery-backed or energy-constrained systems |
| Watchdog Timeout | 1.12s (min) normal mode - provides rapid fault detection after initial 35s startup window |
| Operating Temp | -40°C to +85°C - qualified for industrial and telecom equipment deployed in uncontrolled environments |
Pinout & Package
MAX6729KAYDD3+ uses an 8-pin SOT23-8 package (3.0mm × 1.6mm × 1.1mm), surface-mount, lead-free (+T suffix), RoHS-compliant. Pin 1 marked with dot; pin numbering follows standard SOT23-8 counterclockwise layout.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RST | Active-low push-pull reset output referenced to VCC1; asserts when any monitored supply fails or MR is pulled low |
| 2 | GND | System ground reference for all internal comparators and output drivers |
| 3 | MR | Active-low manual reset input with 50kΩ internal pullup to VCC1; debounced by design, no external RC needed |
| 4 | PFO | Active-low power-fail output (push-pull, VCC1-referenced); asserts independently of reset timeout when PFI < 626.5mV |
| 5 | VCC2 | Secondary supply input powering VCC2 monitor and RST2 logic; also powers internal circuitry when > VCC1 |
| 6 | VCC1 | Primary supply input powering core logic, VCC1 monitor, and RST/PFO drivers; dominant supply rail |
| 7 | PFI | Power-fail comparator noninverting input; high-impedance (±25nA), referenced to 626.5mV internal VREF |
| 8 | WDI | Watchdog input; rising/falling edges clear timer; long (35s) startup then short (1.12s) normal timeout mode |
Key Features
| Feature | Design Value |
|---|---|
| Dual-mode watchdog timer | 35s min startup + 1.12s min normal timeout - accommodates complex boot sequences while enabling fast runtime fault detection |
| Guaranteed reset validity down to 0.8V | Ensures clean reset assertion even during deep brownout conditions where VCC1 or VCC2 drops near device cutoff |
| Adjustable third-voltage monitor (RSTIN) | 626.5mV internal reference enables precise monitoring of sub-1V rails (e.g., 0.9V core, 0.8V FPGA I/O) via external divider |
| Integrated power-fail comparator (PFI/PFO) | Enables early warning shutdown before main supplies collapse - PFO deasserts immediately without timeout delay |
| Immunity to short VCC transients | Rejects glitches <20µs duration (per typical curves), preventing spurious resets during switching noise or load transients |
Applications
| Telecom Line Card Power Management | Industrial PLC CPU Module |
|---|---|
Use Scenario: Monitors +5V (VCC1), +3.3V (VCC2), and +1.2V core rail (via RSTIN) on a carrier-grade line card with hot-swap capability. IC Role / Device Role / Timing Role: Triple-supply supervisor ensuring synchronized reset across analog, digital, and processor domains during power-up, brownout, or manual service reset. Use Value: Prevents partial initialization and latch-up by holding reset until all rails stabilize above their precise thresholds (4.625V/3.075V/1.2V), validated over -40°C to +85°C. |
Use Scenario: Embedded controller in programmable logic controller monitoring 24V DC input (via PFI), 5V logic (VCC1), and 3.3V I/O (VCC2) with watchdog supervision. IC Role / Device Role / Timing Role: Fault-detection hub providing power-fail interrupt (PFO), supervised reset (RST), and software-alive verification (WDI) for deterministic fail-safe behavior. Use Value: Enables graceful shutdown upon 24V sag (via PFI threshold set to 20V), while 210ms reset timeout satisfies PLC boot firmware timing constraints. |
| Battery-Powered Network Router | Medical Diagnostic Handheld |
Use Scenario: Dual-battery system (Li-ion primary + backup coin cell) where VCC1 = 3.6V main rail, VCC2 = 3.0V backup rail, and RSTIN monitors 1.8V RF SoC supply. IC Role / Device Role / Timing Role: Voltage integrity guardian ensuring router remains in known state during battery switchover or low-Vbat conditions. Use Value: 14µA typical supply current extends battery life; 0.8V reset validity guarantees reset assertion even as primary battery discharges to endpoint. |
Use Scenario: Portable ultrasound device requiring fail-safe reset during battery voltage sag, ESD events, or firmware hang detection. IC Role / Device Role / Timing Role: Safety-critical supervisory element asserting hardware reset if 3.3V analog front-end (VCC2) or 1.2V DSP core (RSTIN) drops below threshold. Use Value: Push-pull RST eliminates need for external pullup, reducing BOM count; MR pin enables clinician-initiated hard reset without opening enclosure. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar triple-voltage supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6728KA+T | Same 8-pin SOT23 package and triple-monitor architecture, but features open-drain PFO instead of push-pull | Requires external pullup on PFO for active-high logic interface; less suitable for direct connection to µP interrupt pins expecting active-low drive | Select MAX6728KA+T only if open-drain PFO compatibility with existing pullup network is required |
| TPS3808G33DBVR | Single-supply (VDD only), dual-threshold (3.08V/3.00V), no RSTIN or PFI/PFO; 200ms timeout; SOT23-6 | Lacks third-voltage monitoring and power-fail functionality; cannot replace MAX6729KAYDD3+ in systems requiring RSTIN or PFI-based early warning | Use only in simplified dual-rail systems where RSTIN and PFI are unused and board space is constrained |
Compared with MAX6729KAYDD3+, MAX6728KA+T offers identical monitoring capability but requires external biasing for PFO, while TPS3808G33DBVR reduces feature set and pin count - making it unsuitable for designs relying on adjustable third-rail supervision or integrated power-fail signaling.
Availability
MAX6729KAYDD3+ is available at Aetrix Electronics and suitable for telecom infrastructure, industrial PLCs, and portable medical devices requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.
Supply support for MAX6729KAYDD3+ 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) is a semiconductor company specializing in precision analog, mixed-signal, and power management ICs for demanding industrial, automotive, and communications applications.
The MAX6715–MAX6729 family was designed specifically for multivoltage microprocessor systems needing compact, ultra-low-power supervision with triple-rail monitoring, watchdog, and power-fail alerting - targeting space-constrained, battery-aware, and safety-critical deployments.
FAQ
What is the exact reset timeout period for MAX6729KAYDD3+?
The MAX6729KAYDD3+ has a minimum reset timeout period of 210ms, indicated by the "D3" suffix in its part number. This value is guaranteed over the full -40°C to +85°C operating temperature range and is measured from the moment all monitored supplies exceed their thresholds until reset deassertion. The typical timeout is 210ms, with min/max bounds of 140ms/280ms per the datasheet's Electrical Characteristics table.
Does MAX6729KAYDD3+ support monitoring a 0.9V core supply?
Yes, MAX6729KAYDD3+ supports monitoring a 0.9V core supply using the RSTIN pin. With its internal 626.5mV reference, an external resistor divider can scale the 0.9V rail to match the threshold - for example, R1 = 432kΩ and R2 = 1MΩ yields VRSTIN = 0.9V × (R2/(R1+R2)) ≈ 626.5mV. The 25nA max input current ensures minimal loading and high accuracy.
How does the watchdog timer behave after power-on reset?
After power-on or any reset event, the MAX6729KAYDD3+ watchdog enters a 35s minimum startup period. During this time, no WDI transition is required. Once the first valid WDI edge occurs, the timer switches to normal mode with a 1.12s minimum timeout. If no further edge arrives within that window, RST asserts for 210ms. This dual-mode behavior prevents false timeouts during boot.
Can MAX6729KAYDD3+ generate a power-fail interrupt without resetting the system?
Yes, MAX6729KAYDD3+ can generate a standalone power-fail interrupt via the PFO pin without asserting RST. When the PFI input falls below 626.5mV, PFO goes low immediately - with no reset timeout delay - and returns high as soon as PFI rises above threshold. This enables software-controlled graceful shutdown while keeping the µP running until critical data is saved.
What is the maximum supply voltage the MAX6729KAYDD3+ can tolerate on VCC1 and VCC2?
The MAX6729KAYDD3+ supports absolute maximum supply voltages of +6V on both VCC1 and VCC2, per the Absolute Maximum Ratings table. However, functional operation is specified from 0.8V to 5.5V. Operating above 5.5V risks parametric shift or damage, and the device is not characterized beyond 5.5V - so 5.5V remains the recommended upper limit for reliable performance.
MAX6729KAYDD3+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SOT-23-8
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Type:
- Multi-Voltage Supervisor
- Number of Voltages Monitored:
- 3
- Voltage - Threshold:
- 0.788V, 2.188V, Adj
- Output:
- Push-Pull, Totem Pole
- 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
MAX6729KAYDD3+ FAQ
1.How can I place an order for MAX6729KAYDD3+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6729KAYDD3+ 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 MAX6729KAYDD3+ reliable?
The price and inventory of MAX6729KAYDD3+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6729KAYDD3+ is usually 5 days.
3.What payment methods are accepted for MAX6729KAYDD3+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6729KAYDD3+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6729KAYDD3+?
MAX6729KAYDD3+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6729KAYDD3+ 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 MAX6729KAYDD3+?
For technical support, including MAX6729KAYDD3+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6729KAYDD3+ requirements.
6.How does Aetrix verify that MAX6729KAYDD3+ is sourced from the original manufacturer or authorized distributors?
All MAX6729KAYDD3+ 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 MAX6729KAYDD3+ meets industry standards.
7.What is the process for return or replacement of MAX6729KAYDD3+?
All MAX6729KAYDD3+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX6729KAYDD3+, 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 MAX6729KAYDD3+ part is unused and in its original packaging.
Return procedure for MAX6729KAYDD3+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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