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Analog Devices Inc./Maxim Integrated MAX6729KAYHD3+
- Part No.:
- MAX6729KAYHD3+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SOT-23-8
- Datasheet:
-
MAX6729KAYHD3+.pdf
- Description:
- IC SUPERVISOR 3 CHANNEL SOT23-8
- Quantity:
- Payment:
- Shipping:
Inventory:1,462
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Product details
Overview
MAX6729KAYHD3+ from Maxim Integrated is a triple-voltage microprocessor supervisory circuit in an 8-pin SOT23 package, monitoring VCC1 (1.575V threshold), VCC2 (0.788V threshold), and an externally adjustable RSTIN input (626.5mV reference). It provides push-pull active-low reset output, power-fail input/output (PFI/PFO), manual reset (MR), and watchdog timer with 35s startup / 1.12s normal timeout. Used in multivoltage telecom and industrial systems requiring reliable brownout detection and orderly shutdown.
For engineers reviewing the MAX6729KAYHD3+ datasheet, MAX6729KAYHD3+ pinout, MAX6729KAYHD3+ application, or MAX6729KAYHD3+ equivalent, key selection criteria include its triple-supply monitoring capability, guaranteed reset validity down to VCC1/VCC2 = 0.8V, push-pull RST output referenced to VCC1, PFO with push-pull drive, and factory-trimmed dual-threshold configuration with 210ms (min) reset timeout.
Technical Context
The MAX6729KAYHD3+ integrates three independent voltage monitors: primary (VCC1), secondary (VCC2), and auxiliary (RSTIN), each with dedicated comparators and hysteresis. Its reset logic asserts RST low when any monitored voltage falls below its threshold and holds for a minimum 210ms timeout after all voltages recover - with internal timer restart on re-fall before timeout completion.
This device implements a dual-mode watchdog: a 35s minimum initial timeout after power-up/manual reset, followed by a 1.12s minimum normal timeout triggered by the first WDI edge; PFI feeds a dedicated comparator driving PFO with 2µs typical delay and 3mV hysteresis, enabling early power-fail warning without reset assertion.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC1 Threshold | 1.575V (typ), factory-trimmed; ensures reliable reset assertion during 1.8V rail brownout |
| VCC2 Threshold | 0.788V (typ), factory-trimmed; supports monitoring of sub-1V core supplies like 0.9V DSPs |
| RSTIN Reference | 626.5mV (typ); enables precise third-supply monitoring via external resistor divider |
| Reset Timeout | 210ms (min); guarantees sufficient hold time for processor initialization and memory stabilization |
| Supply Current | 14µA (typ at 3.6V); minimizes quiescent load in battery-operated or always-on systems |
| Operating Temp | -40°C to +85°C; qualified for industrial and telecom equipment environments |
| PFO Drive Type | Push-pull active-low; eliminates need for external pullup and simplifies interrupt signaling |
Pinout & Package
MAX6729KAYHD3+ is housed in an 8-pin SOT23-8 package (2.0mm × 2.1mm × 1.25mm), thermally enhanced with exposed pad for improved power dissipation in compact layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RST | Active-low push-pull reset output referenced to VCC1; asserts low on fault and holds for 210ms min |
| 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; forces reset when pulled low |
| 4 | PFO | Active-low push-pull power-fail output; asserts independently of reset when PFI < 626.5mV |
| 5 | VCC2 | Secondary supply input (0.9V–3.3V range); powers internal VCC2 monitor and RST2 logic |
| 6 | VCC1 | Primary supply input (1.8V–5.0V range); powers main circuitry and references RST/PFO outputs |
| 7 | PFI | Power-fail comparator noninverting input; high-impedance node for setting fail threshold via resistor divider |
| 8 | WDI | Watchdog input; resets internal timer on rising/falling edge; triggers reset if idle > 1.12s (normal mode) |
Key Features
| Feature | Design Value |
|---|---|
| Dual factory-trimmed thresholds | VCC1 = 1.575V and VCC2 = 0.788V enable precise, zero-calibration monitoring of 1.8V/0.9V rail pairs |
| Externally adjustable RSTIN | 626.5mV internal reference allows third-supply monitoring down to 0.62V with <25nA input bias current |
| Dual-mode watchdog timer | 35s startup + 1.12s normal timeout prevents false resets during boot while ensuring rapid fault response in runtime |
| Guaranteed reset validity to 0.8V | Ensures clean reset assertion even during deep brownout conditions where VCC1 or VCC2 drops to 0.8V |
| Push-pull PFO output | Eliminates external pullup requirement and provides robust interrupt signaling to µP without bus contention |
Applications
| Telecom Power Sequencing | Industrial PLC I/O Modules |
|---|---|
|
Use Scenario: Monitoring 3.3V backplane, 1.2V FPGA core, and -12V analog supply in carrier-grade line cards. IC Role / Device Role / Timing Role: Triple-voltage supervisor asserting RST on any rail collapse and PFO on negative supply decay. Use Value: Prevents partial initialization and latch-up by enforcing coordinated reset across mixed-signature rails. |
Use Scenario: Ensuring safe startup/shutdown of 24V field power, 5V logic, and 3.3V MCU in programmable logic controllers. IC Role / Device Role / Timing Role: Simultaneous VCC1/VCC2/RSTIN monitoring with MR-triggered firmware recovery and PFO-driven emergency stop. Use Value: Enables deterministic state recovery and failsafe I/O isolation during brownout or power-fail events. |
| Battery-Powered Medical Sensors | Set-Top Box Power Management |
|
Use Scenario: Supervising Li-ion battery (3.0V), LDO output (1.8V), and sensor bias (0.9V) in portable ECG units. IC Role / Device Role / Timing Role: Low-current (14µA) triple-monitor with 210ms reset hold and WDI-driven firmware watchdog. Use Value: Extends battery life while guaranteeing clean reboot before data corruption occurs during voltage sag. |
Use Scenario: Coordinating 12V SMPS, 3.3V SoC rail, and 1.1V DDR termination in digital video receivers. IC Role / Device Role / Timing Role: Dual-threshold supervision plus PFI-driven PFO for early AC loss detection and graceful OS shutdown. Use Value: Avoids filesystem corruption by triggering software-initiated power-down before VCC1 collapses. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar triple-voltage supervisory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX6728KAHBD3+ | Same pinout and thresholds, but open-drain PFO instead of push-pull | Requires external pullup for PFO; suitable where interrupt line sharing is needed | Select when system-level bus arbitration requires open-drain PFO behavior |
| TPS3808G33DBVR | Dual-supply monitor only (no RSTIN or PFI); 3.3V fixed VDD threshold; 200ms timeout | Lacks third-supply monitoring and power-fail functionality; simpler BOM | Choose only if triple-monitoring and PFI/PFO are not required |
Compared with MAX6729KAYHD3+, MAX6728KAHBD3+ offers identical supervision and timing but requires external pullup for PFO, while TPS3808G33DBVR reduces feature set to dual monitoring only - making MAX6729KAYHD3+ the sole option supporting simultaneous VCC1/VCC2/RSTIN monitoring with integrated push-pull PFO and watchdog in SOT23-8.
Availability
MAX6729KAYHD3+ is available at Aetrix Electronics and suitable for telecom infrastructure, industrial PLCs, and medical sensor designs requiring stable component supply, long-lifecycle assurance, and guaranteed reset validity down to 0.8V.
Supply support for MAX6729KAYHD3+ 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 MAX6715–MAX6729 family delivers ultra-low-voltage, multi-rail supervision in miniature SOT23 packages - engineered specifically for space-constrained, multivoltage systems needing deterministic reset, power-fail warning, and watchdog safety.
FAQ
What is the exact reset threshold voltage for VCC1 on MAX6729KAYHD3+?
The MAX6729KAYHD3+ has a factory-trimmed VCC1 reset threshold of 1.575V (typical), with a guaranteed range of 1.530V to 1.620V over temperature. This value is encoded in the "Y" suffix per Maxim's Reset Voltage Threshold Suffix Guide and applies specifically to the MAX6729KAYHD3+ variant - not the broader MAX6729 family.
Does MAX6729KAYHD3+ support monitoring a negative supply voltage?
Yes, MAX6729KAYHD3+ can monitor negative supplies using the PFI input with an external resistor network as shown in Figure 3b of the datasheet. When the negative rail drops, PFI falls below 626.5mV and PFO asserts low - enabling early warning without resetting the system. The accuracy depends on resistor tolerance and PFI input bias (<25nA).
What is the function of the WDI pin on MAX6729KAYHD3+ and how is it timed?
The WDI pin on MAX6729KAYHD3+ enables dual-mode watchdog operation: after reset, it enters a 35s minimum startup period, then switches to a 1.12s minimum normal timeout upon first valid edge. If WDI remains static beyond the active timeout, MAX6729KAYHD3+ asserts RST for 210ms. Edges must exceed 50ns pulse width and meet VIH/VIL thresholds relative to VCC1.
How does the PFO output behave relative to reset assertion on MAX6729KAYHD3+?
On MAX6729KAYHD3+, PFO operates independently of the reset function: it asserts low when PFI < 626.5mV and deasserts immediately when PFI rises above threshold - with no timeout delay. This allows real-time power-fail interrupt generation while RST maintains its 210ms hold time for processor recovery, supporting both fast alerting and safe reboot.
Is MAX6729KAYHD3+ compatible with 1.8V-only systems lacking a secondary supply?
Yes, MAX6729KAYHD3+ functions correctly in 1.8V-only systems: VCC2 may be tied to GND or left floating (per datasheet guidance), and the VCC2 monitor is disabled. VCC1 (1.575V threshold) and RSTIN remain fully operational, preserving triple-monitor capability for VCC1, auxiliary rail, and PFI - with reset asserted only on violations of active thresholds.
MAX6729KAYHD3+ 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:
- 1.313V, 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
MAX6729KAYHD3+ FAQ
1.How can I place an order for MAX6729KAYHD3+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6729KAYHD3+ 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 MAX6729KAYHD3+ reliable?
The price and inventory of MAX6729KAYHD3+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6729KAYHD3+ is usually 5 days.
3.What payment methods are accepted for MAX6729KAYHD3+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6729KAYHD3+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6729KAYHD3+?
MAX6729KAYHD3+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6729KAYHD3+ 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 MAX6729KAYHD3+?
For technical support, including MAX6729KAYHD3+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6729KAYHD3+ requirements.
6.How does Aetrix verify that MAX6729KAYHD3+ is sourced from the original manufacturer or authorized distributors?
All MAX6729KAYHD3+ 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 MAX6729KAYHD3+ meets industry standards.
7.What is the process for return or replacement of MAX6729KAYHD3+?
All MAX6729KAYHD3+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX6729KAYHD3+, 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 MAX6729KAYHD3+ part is unused and in its original packaging.
Return procedure for MAX6729KAYHD3+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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