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Analog Devices Inc./Maxim Integrated MAX6729KALTD3+
- Part No.:
- MAX6729KALTD3+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Supervisors
- Package:
- SOT-23-8
- Datasheet:
-
MAX6729KALTD3+.pdf
- Description:
- IC SUPERVISOR MPU SOT23-8
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
MAX6729KALTD3+ from Maxim Integrated is a triple-voltage microprocessor supervisory circuit in an 8-pin SOT23 package, monitoring VCC1 (4.625V threshold), VCC2 (3.075V threshold), and an auxiliary voltage via RSTIN (626.5mV reference). It provides push-pull active-low reset output, power-fail input/output (PFI/PFO), manual reset input (MR), and watchdog timer with 35s startup / 1.12s normal timeout. Used in telecom power sequencing and multivoltage server management.
For engineers reviewing the MAX6729KALTD3+ datasheet, MAX6729KALTD3+ pinout, MAX6729KALTD3+ application, or MAX6729KALTD3+ equivalent, key selection criteria include guaranteed reset validity down to VCC1/VCC2 = 0.8V, 14µA typical supply current at 3.6V, 22µs RSTIN-to-reset delay, and compatibility with battery-backed systems requiring precise undervoltage detection across three rails.
Technical Context
The MAX6729KALTD3+ integrates dual independent voltage comparators for VCC1 and VCC2 plus a high-impedance RSTIN comparator referenced to a 626.5mV internal bandgap. Its reset logic asserts RST low when any monitored rail falls below its factory-trimmed threshold and holds for a minimum 210ms timeout after all rails recover.
It features a dual-mode watchdog timer: 35s minimum initial timeout after power-up or reset, then 1.12s minimum normal timeout after first WDI edge; PFO operates independently of reset timing with 2µs propagation delay from PFI to PFO and no timeout delay on deassertion.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC1 Reset Threshold | 4.625V (factory-trimmed, ±125mV tolerance) - sets primary supply brownout detection point for 5V/4.8V system rails |
| VCC2 Reset Threshold | 3.075V (factory-trimmed, ±75mV tolerance) - enables reliable monitoring of 3.3V I/O or intermediate supply rails |
| RSTIN Reference Voltage | 626.5mV (±15.5mV) - allows external resistor-divider to monitor third supply as low as 0.62V with <25nA input bias |
| Reset Timeout Period | 210ms (typical), min 140ms - ensures sufficient hold time for processor initialization and memory stabilization |
| Supply Current | 14µA (typ) at 3.6V - supports ultra-low-power operation in battery-critical applications like portable networking gear |
| Watchdog Timeout | 1.12s (min) normal mode - provides rapid fault detection during runtime without false triggers during boot |
| Operating Temperature | -40°C to +85°C - qualified for industrial and telecom equipment deployed in uncontrolled environments |
Pinout & Package
MAX6729KALTD3+ uses an 8-pin SOT23-8 package with exposed pad (thermal enhancement), footprint compatible with industry-standard 8-pin SOT23 layouts. Pin 1 is marked by dot; device orientation follows JEDEC MO-203AA standard.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | RST | Active-low push-pull reset output referenced to VCC1; sinks 3.2mA at VCC1 ≥ 4.5V; no external pullup required |
| 2 | GND | Analog/digital ground reference; must be connected to system ground plane with low-inductance path |
| 3 | MR | Active-low manual reset input with 50kΩ internal pullup to VCC1; 1µs minimum pulse width; immune to <100ns glitches |
| 4 | PFO | Active-low push-pull power-fail output referenced to VCC1; asserts when PFI < 626.5mV; no timeout delay on deassertion |
| 5 | VCC2 | Secondary supply input (0.9V–3.3V range); powers internal VCC2 comparator and RST2 logic (not used in MAX6729) |
| 6 | VCC1 | Primary supply input (1.8V–5.0V range); powers core logic, VCC1 comparator, and RST/PFO drivers |
| 7 | PFI | Power-fail input with 626.5mV internal reference; high-impedance node (<25nA bias) for resistor-divider monitoring of auxiliary supplies |
| 8 | WDI | Watchdog input; resets internal timer on rising/falling edge; long startup mode (35s) transitions to short mode (1.12s) after first valid edge |
Key Features
| Feature | Design Value |
|---|---|
| Triple-voltage supervision | Simultaneous monitoring of VCC1 (4.625V), VCC2 (3.075V), and auxiliary rail via RSTIN/PFI with single IC reduces BOM count vs. discrete solutions |
| Guaranteed reset validity | Reset output remains logically valid even when VCC1 or VCC2 drops to 0.8V - critical for graceful shutdown in brownout conditions |
| Dual-mode watchdog timer | 35s startup timeout prevents spurious resets during boot; 1.12s runtime timeout detects software hangs without compromising initialization time |
| Push-pull RST and PFO outputs | Eliminates need for external pullup resistors, reducing board space and enabling direct interface to µP reset pins without contention risk |
| Low 14µA supply current | Enables use in always-on subsystems (e.g., RTC backup, wake-on-LAN circuits) without significant battery drain over years |
Applications
| Telecom Power Sequencing | Server Board Management |
|---|---|
|
Use Scenario: Monitoring primary 48V DC-DC converter output, intermediate 12V bus, and 3.3V management controller supply in carrier-grade routers. IC Role / Device Role / Timing Role: MAX6729KALTD3+ asserts RST only after all three rails stabilize above thresholds and maintains reset for 210ms to ensure FPGA configuration completes before CPU release. Use Value: Prevents partial initialization failures caused by uneven rail ramp rates; eliminates need for discrete RC timers or FPGA-based sequencing logic. |
Use Scenario: Supervising 5V standby, 3.3V main, and 1.8V core voltages on x86 server motherboard with IPMI BMC integration. IC Role / Device Role / Timing Role: MAX6729KALTD3+ uses PFI to monitor 5VSB rail and drives PFO to BMC interrupt line, enabling early power-fail warning before VCC1 collapse. Use Value: Enables OS-level graceful shutdown within 2µs of PFI threshold breach - 100× faster than polling-based detection. |
| Industrial PLC I/O Module | Battery-Backed Network Appliance |
|
Use Scenario: Ensuring deterministic reset behavior across 24V field bus, 5V logic, and 3.3V sensor interface rails in harsh EMI environments. IC Role / Device Role / Timing Role: MAX6729KALTD3+ leverages MR input for emergency hardware reset triggered by front-panel button, with glitch rejection filtering noise from relay contacts. Use Value: Guarantees reset assertion even if 24V rail dips to 0.8V during motor switching transients - avoids firmware lockup in safety-critical loops. |
Use Scenario: Maintaining system integrity in 4G/LTE CPE devices powered by Li-ion battery with 3.7V nominal, 2.8V cutoff, and 3.3V LDO output. IC Role / Device Role / Timing Role: MAX6729KALTD3+ monitors battery voltage via RSTIN divider (set to 2.9V trip), asserting RST at 2.85V to initiate controlled save-and-shutdown sequence. Use Value: Achieves 0.05V hysteresis using internal 3mV comparator hysteresis plus external resistor network - prevents oscillation near battery cutoff. |
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 | Identical pinout and electrical specs except PFO is open-drain (requires external pullup) vs. push-pull in MAX6729KALTD3+ | Suitable where PFO must drive multiple loads or interface to different voltage domains via level-shifting | Select MAX6728KA+T when PFO load requires higher sink current or isolation from VCC1 rail |
| TPS3808G33DBVR | Dual-voltage supervisor only (VDD1/VDD2), no RSTIN/PFI/WDI; 3.3V fixed VDD1 threshold; 200ms timeout; 1.6µA quiescent current | Limited to two-rail systems; lacks auxiliary monitoring and watchdog functionality | Choose TPS3808G33DBVR for cost-sensitive dual-rail designs where third-rail monitoring is handled separately |
Compared with MAX6728KA+T, MAX6729KALTD3+ eliminates external pullup components for PFO, simplifying layout; versus TPS3808G33DBVR, it adds critical third-rail supervision and watchdog capability essential for complex embedded systems.
Availability
MAX6729KALTD3+ is available at Aetrix Electronics and suitable for telecom infrastructure, server board management, industrial PLCs, and battery-backed network appliances requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for MAX6729KALTD3+ 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 management, sensing, and interface applications in industrial, automotive, and communications markets.
The MAX6715–MAX6729 family delivers compact, ultra-low-power supervisory solutions optimized for multivoltage systems where reliability, small footprint, and guaranteed operation down to 0.8V are mandatory design requirements.
FAQ
What is the exact reset threshold voltage for VCC1 on MAX6729KALTD3+?
The MAX6729KALTD3+ has a factory-trimmed VCC1 reset threshold of 4.625V, with a guaranteed tolerance of ±125mV (4.500V to 4.750V) over -40°C to +85°C. This value is encoded in the "LA" suffix per Maxim's Reset Voltage Threshold Suffix Guide and applies specifically to the MAX6729KALTD3+ variant.
Does MAX6729KALTD3+ support monitoring a negative supply voltage?
Yes, MAX6729KALTD3+ can monitor negative supplies using the PFI input with an external resistor divider configured per Figure 3b in the datasheet. When the negative rail drops, PFI falls below 626.5mV and PFO asserts low - enabling early warning for systems with split-rail power architectures.
What is the function of the WDI pin on MAX6729KALTD3+ and how does its dual-mode timeout work?
The WDI pin on MAX6729KALTD3+ enables watchdog functionality: after each reset event, it enters a 35s minimum startup mode to allow full system boot, then transitions to 1.12s minimum normal mode upon first WDI edge. This prevents false timeouts during initialization while ensuring rapid fault detection during runtime.
Can MAX6729KALTD3+ operate with VCC1 below 1.8V?
Yes, MAX6729KALTD3+ guarantees correct reset output logic state with VCC1 or VCC2 as low as 0.8V. However, VCC1 must remain ≥0.8V for the device to function - operation below this violates Absolute Maximum Ratings and may cause undefined behavior or damage.
How does the RSTIN input on MAX6729KALTD3+ differ from the PFI input?
RSTIN on MAX6729KALTD3+ is an undervoltage reset comparator input tied to the same 626.5mV reference as PFI but directly controls the main RST output assertion. PFI drives the independent PFO output with no reset timeout delay, making RSTIN ideal for critical third-rail reset generation and PFI better suited for non-reset power-fail interrupts.
MAX6729KALTD3+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- SOT-23-8
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Multi-Voltage Supervisor
- Number of Voltages Monitored:
- 3
- Voltage - Threshold:
- 3.075V, 4.625V, 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
MAX6729KALTD3+ FAQ
1.How can I place an order for MAX6729KALTD3+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX6729KALTD3+ 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 MAX6729KALTD3+ reliable?
The price and inventory of MAX6729KALTD3+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6729KALTD3+ is usually 5 days.
3.What payment methods are accepted for MAX6729KALTD3+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6729KALTD3+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX6729KALTD3+?
MAX6729KALTD3+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX6729KALTD3+ 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 MAX6729KALTD3+?
For technical support, including MAX6729KALTD3+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6729KALTD3+ requirements.
6.How does Aetrix verify that MAX6729KALTD3+ is sourced from the original manufacturer or authorized distributors?
All MAX6729KALTD3+ 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 MAX6729KALTD3+ meets industry standards.
7.What is the process for return or replacement of MAX6729KALTD3+?
All MAX6729KALTD3+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX6729KALTD3+, 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 MAX6729KALTD3+ part is unused and in its original packaging.
Return procedure for MAX6729KALTD3+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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