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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Supervisors

Analog Devices Inc./Maxim Integrated MAX6729KAWGD3+

Name: MAX6729KAWGD3+
Brand: Analog Devices Inc./Maxim Integrated
SKU: MAX6729KAWGD3+
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MAX6729KAWGD3+

Manufacturer:: Analog Devices Inc./Maxim Integrated

Category:: Supervisors

Package:: SOT-23-8

Datasheet:: MAX6729KAWGD3+.pdf

Description:: IC SUPERVISOR 3 CHANNEL SOT23-8

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Product details

Overview

MAX6729KAWGD3+ from Maxim Integrated is a triple-voltage microprocessor supervisory circuit in an 8-pin SOT23 package, monitoring VCC1 (1.575V threshold), VCC2 (3.075V threshold), and RSTIN (626.5mV reference) with push-pull active-low reset output, power-fail input/output (PFI/PFO), manual reset (MR), and watchdog timer (WDI). It guarantees valid reset assertion down to VCC1 or VCC2 = 0.8V and supports telecom equipment, industrial controllers, and battery-powered systems requiring reliable multi-rail power monitoring.

For engineers reviewing the MAX6729KAWGD3+ datasheet, MAX6729KAWGD3+ pinout, MAX6729KAWGD3+ application, or MAX6729KAWGD3+ equivalent, key selection criteria include its triple-supply monitoring capability, 210ms (min) reset timeout, push-pull RST output referenced to VCC1, integrated PFO with 2µs propagation delay, and guaranteed operation at ultra-low supply voltages - all critical for embedded systems with tight power integrity requirements.

Technical Context

The MAX6729KAWGD3+ implements dual independent voltage comparators for VCC1 and VCC2 plus a dedicated adjustable comparator for RSTIN (with internal 626.5mV reference), enabling precise triple-rail supervision. Its reset logic combines OR-ed fault conditions (VCC1/VCC2 undervoltage, RSTIN low, MR low, or WDI timeout) with a monolithic timeout counter that restarts on any new fault before timeout completion.

This device integrates a dual-mode watchdog timer: a 35s (min) startup period after reset events followed by a 1.12s (min) normal timeout period triggered by the first WDI edge; it also features a power-fail comparator with 3mV hysteresis and 2µs PFI-to-PFO delay, supporting early warning shutdown via PFO assertion without reset timeout dependency.

Key Specifications

Parameter	Value and Actual Design Meaning
VCC1 Reset Threshold	1.575V (typ), factory-trimmed - ensures reliable reset assertion when primary supply drops below nominal 1.6V rail, e.g., in 1.8V-core systems under brownout.
VCC2 Reset Threshold	3.075V (typ), factory-trimmed - monitors secondary 3.3V I/O supply with ±75mV tolerance, preventing false resets during transient dips.
RSTIN Reference Voltage	626.5mV (typ), internal - enables external resistor-divider setup for third-voltage monitoring down to 0.62V, ideal for auxiliary rails or battery voltage tracking.
Reset Timeout Period	210ms (min), D3 suffix - provides sufficient hold time for slow-starting DC/DC converters or FPGA configuration sequences before release.
Supply Current	14µA (typ) at 3.6V - minimizes quiescent load on battery-backed or energy-constrained subsystems without sacrificing supervision accuracy.
Watchdog Timeout	1.12s (min) normal mode - detects processor lockup within sub-second window while allowing 35s boot margin for complex firmware initialization.
PFI-to-PFO Delay	2µs (typ) - delivers near-instantaneous power-fail interrupt signaling for real-time software shutdown, independent of reset timing.

Pinout & Package

MAX6729KAWGD3+ is housed in an 8-pin SOT23-8 package (2.0mm × 2.5mm, 0.95mm height), optimized for space-constrained PCB layouts in portable and industrial applications.

Pin/Terminal	Circuit Role	Design Meaning
1	RST	Active-low push-pull reset output referenced to VCC1; drives high to ≥0.8×VCC1 when deasserted, sinks ≤0.4V at 3.2mA when asserted - eliminates need for external pullup in most designs.
2	GND	System ground reference for all internal comparators and logic - must be low-impedance connection to avoid threshold shift or noise coupling.
3	MR	Active-low manual reset input with 50kΩ internal pullup to VCC1; accepts TTL/CMOS levels; 1µs minimum pulse width ensures robust switch debouncing without external RC.
4	PFO	Active-low push-pull power-fail output referenced to VCC1; asserts when PFI < 626.5mV; deasserts immediately (no timeout) - used for interrupt generation or auxiliary reset control.
5	VCC2	Secondary supply input (0.9V–3.3V range); powers internal VCC2 comparator and sets RST2 reference if enabled - allows independent monitoring of I/O or analog rails.
6	VCC1	Primary supply input (1.8V–5.0V range); powers core logic, VCC1 comparator, and references RST and PFO outputs - defines main system voltage domain.
7	PFI	Power-fail input with 626.5mV internal reference; high-impedance (±25nA) node for resistor-divider monitoring of auxiliary supplies - enables early warning of battery depletion or AC loss.
8	WDI	Watchdog input with 0.3×VCC1/0.7×VCC1 logic thresholds; clears timer on rising/falling edges; immune to glitches <100ns - requires periodic toggling to prevent timeout-induced reset.

Key Features

Feature	Design Value
Triple-voltage supervision	Simultaneously monitors VCC1 (1.575V), VCC2 (3.075V), and RSTIN (626.5mV reference) - eliminates need for three discrete supervisors in multirail systems like baseband processors or mixed-signal SoMs.
Dual-mode watchdog timer	35s startup + 1.12s normal timeout - accommodates lengthy boot sequences while maintaining rapid lockup detection during runtime, reducing firmware complexity.
Push-pull RST and PFO outputs	No external pullup required; RST drives high to ≥0.8×VCC1, PFO deasserts instantly - simplifies interface to µP reset pins and reduces BOM count vs. open-drain alternatives.
Guaranteed reset validity to 0.8V	Operates correctly even as VCC1 or VCC2 decays to 0.8V - ensures clean reset assertion during deep brownouts where other supervisors may fail.
Low 14µA supply current	Enables always-on supervision in battery-critical applications (e.g., smart meters, IoT sensors) without compromising runtime or requiring duty-cycled monitoring.

Applications

Telecom Line Card Power Monitoring	Industrial PLC I/O Module
Use Scenario: Monitors +3.3V I/O bus, +1.8V FPGA core, and -48V backup battery feed via resistor divider on PFI in carrier-grade line cards. IC Role / Device Role / Timing Role: MAX6729KAWGD3+ acts as centralized power supervisor, asserting RST during VCC1/VCC2 brownout and generating immediate PFO interrupt on battery sag for graceful switchover. Use Value: Prevents data corruption during AC loss by triggering controlled shutdown before backup rail collapses, leveraging 2µs PFI→PFO delay and 210ms reset hold.	Use Scenario: Supervises 24V DC input (via PFI divider), 5V logic rail (VCC1), and 3.3V microcontroller core (VCC2) in DIN-rail mounted PLC modules. IC Role / Device Role / Timing Role: MAX6729KAWGD3+ provides triple-rail fault detection, manual reset via front-panel button (MR), and watchdog supervision of ARM Cortex-M firmware execution. Use Value: Eliminates need for separate PFI comparator and reset IC, reducing footprint by 40% vs. discrete solution while ensuring deterministic reset behavior across wide temperature (-40°C to +85°C).
Portable Medical Device Battery Management	Set-Top Box Power Sequencing
Use Scenario: Tracks Li-ion battery voltage (RSTIN), 3.3V system rail (VCC1), and 1.2V sensor analog supply (VCC2) in handheld ultrasound units. IC Role / Device Role / Timing Role: MAX6729KAWGD3+ initiates emergency shutdown when battery drops below 3.2V (via RSTIN divider), holds reset for 210ms to allow EEPROM save, and monitors for processor hang via WDI. Use Value: Enables safe data preservation during battery exhaustion using 626.5mV precision reference and ultra-low 14µA quiescent current - extends usable runtime by >12% vs. higher-I_CC alternatives.	Use Scenario: Controls power-up sequence of 12V SMPS, 5V USB hub, and 1.1V SoC core in cable TV set-top boxes with HDMI and Ethernet interfaces. IC Role / Device Role / Timing Role: MAX6729KAWGD3+ verifies all three rails are stable before releasing RST, uses PFO to signal "power-good" to downstream PMICs, and watches firmware via WDI during boot. Use Value: Guarantees correct sequencing across diverse voltage domains with single-chip integration, avoiding timing mismatches that cause HDMI handshake failures or Ethernet PHY lockup.

Telecom Line Card Power Monitoring

Industrial PLC I/O Module

Use Scenario: Monitors +3.3V I/O bus, +1.8V FPGA core, and -48V backup battery feed via resistor divider on PFI in carrier-grade line cards.

IC Role / Device Role / Timing Role: MAX6729KAWGD3+ acts as centralized power supervisor, asserting RST during VCC1/VCC2 brownout and generating immediate PFO interrupt on battery sag for graceful switchover.

Use Value: Prevents data corruption during AC loss by triggering controlled shutdown before backup rail collapses, leveraging 2µs PFI→PFO delay and 210ms reset hold.

Use Scenario: Supervises 24V DC input (via PFI divider), 5V logic rail (VCC1), and 3.3V microcontroller core (VCC2) in DIN-rail mounted PLC modules.

IC Role / Device Role / Timing Role: MAX6729KAWGD3+ provides triple-rail fault detection, manual reset via front-panel button (MR), and watchdog supervision of ARM Cortex-M firmware execution.

Use Value: Eliminates need for separate PFI comparator and reset IC, reducing footprint by 40% vs. discrete solution while ensuring deterministic reset behavior across wide temperature (-40°C to +85°C).

Portable Medical Device Battery Management

Set-Top Box Power Sequencing

Use Scenario: Tracks Li-ion battery voltage (RSTIN), 3.3V system rail (VCC1), and 1.2V sensor analog supply (VCC2) in handheld ultrasound units.

IC Role / Device Role / Timing Role: MAX6729KAWGD3+ initiates emergency shutdown when battery drops below 3.2V (via RSTIN divider), holds reset for 210ms to allow EEPROM save, and monitors for processor hang via WDI.

Use Value: Enables safe data preservation during battery exhaustion using 626.5mV precision reference and ultra-low 14µA quiescent current - extends usable runtime by >12% vs. higher-I_CC alternatives.

Use Scenario: Controls power-up sequence of 12V SMPS, 5V USB hub, and 1.1V SoC core in cable TV set-top boxes with HDMI and Ethernet interfaces.

IC Role / Device Role / Timing Role: MAX6729KAWGD3+ verifies all three rails are stable before releasing RST, uses PFO to signal "power-good" to downstream PMICs, and watches firmware via WDI during boot.

Use Value: Guarantees correct sequencing across diverse voltage domains with single-chip integration, avoiding timing mismatches that cause HDMI handshake failures or Ethernet PHY lockup.

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 pinout and feature set but open-drain PFO output instead of push-pull; identical VTH1/VTH2/RSTIN specs and D3 timeout.	Requires external pullup on PFO for interrupt signaling; suitable where level-shifting or wired-OR is needed.	Select MAX6728KA+T only if open-drain PFO is required for bus sharing; otherwise MAX6729KAWGD3+ simplifies design with push-pull drive.
TPS3808G33DBVR	Dual-supply monitor (VDD/VDD2) only; no RSTIN or PFI/PFO; fixed 3.3V threshold on VDD, 2.93V on VDD2; 200ms timeout.	Lacks third-voltage monitoring and power-fail functionality; limited to two-rail systems without auxiliary supply tracking.	Choose TPS3808G33DBVR only for cost-sensitive dual-rail applications without PFI/RSTIN needs; MAX6729KAWGD3+ adds critical third-rail and PFI capability.

Compared with MAX6728KA+T and TPS3808G33DBVR, the MAX6729KAWGD3+ uniquely delivers integrated push-pull PFO, triple-supply monitoring with adjustable RSTIN, and guaranteed 0.8V operation - making it the only option for compact, battery-aware systems requiring both power-fail interrupt and brownout reset in one 8-pin package.

Availability

MAX6729KAWGD3+ is available at Aetrix Electronics and suitable for telecom infrastructure, industrial automation, and portable medical devices requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for MAX6729KAWGD3+ 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 leader specializing in high-performance analog, mixed-signal, and power management ICs for demanding industrial, communications, and computing applications.

The MAX6715–MAX6729 family was designed specifically for ultra-low-voltage, multi-rail microprocessor supervision in space- and power-constrained systems - emphasizing precision threshold matching, minimal quiescent current, and robust glitch immunity.

FAQ

What are the factory-trimmed reset thresholds for MAX6729KAWGD3+?

The MAX6729KAWGD3+ has VCC1 reset threshold of 1.575V (typ) and VCC2 reset threshold of 3.075V (typ), as indicated by the 'K' and 'W' suffixes per Maxim's Reset Voltage Threshold Suffix Guide. These values are laser-trimmed at wafer test and guaranteed over -40°C to +85°C with ±1.5% tolerance, enabling accurate supervision of 1.6V and 3.3V rails without external calibration.

Does MAX6729KAWGD3+ support monitoring a negative supply voltage?

Yes, MAX6729KAWGD3+ 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 - providing interrupt capability for battery backup or AC-loss detection in systems like set-top boxes or industrial gateways.

How does the watchdog timer in MAX6729KAWGD3+ behave after power-up?

After power-up or any reset event, MAX6729KAWGD3+ enters a 35s (min) long initial watchdog period, allowing ample time for firmware initialization. Once the first valid WDI edge occurs, it switches to 1.12s (min) normal timeout mode - ensuring rapid detection of subsequent hangs while accommodating complex boot sequences.

What is the maximum allowable VCC transient duration before MAX6729KAWGD3+ asserts reset?

Per the Typical Operating Characteristics graph (toc06), MAX6729KAWGD3+ tolerates VCC transients up to ~10µs when the overdrive is 100mV below threshold, and down to ~1µs at 300mV overdrive. This immunity prevents spurious resets from switching noise, especially when combined with a 0.1µF bypass capacitor placed close to the VCC1 pin.

Can MAX6729KAWGD3+ operate with VCC1 = 1.8V and VCC2 = 1.2V simultaneously?

Yes, MAX6729KAWGD3+ supports VCC1 as low as 1.8V and VCC2 as low as 0.9V per datasheet specifications. With VCC1 = 1.8V and VCC2 = 1.2V, it maintains full functionality including RST assertion, MR response, and WDI monitoring - validated across -40°C to +85°C with typical supply current of 10µA (ICC1) + 4µA (ICC2).

MAX6729KAWGD3+ 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:: 1.11V, 1.665V, 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

MAX6729KAWGD3+ FAQ

1.How can I place an order for MAX6729KAWGD3+ through Aetrix?

Please submit a Request for Quotation (RFQ) for MAX6729KAWGD3+ 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 MAX6729KAWGD3+ reliable?

The price and inventory of MAX6729KAWGD3+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX6729KAWGD3+ is usually 5 days.

3.What payment methods are accepted for MAX6729KAWGD3+?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX6729KAWGD3+ transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MAX6729KAWGD3+?

MAX6729KAWGD3+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MAX6729KAWGD3+ 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 MAX6729KAWGD3+?

For technical support, including MAX6729KAWGD3+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX6729KAWGD3+ requirements.

6.How does Aetrix verify that MAX6729KAWGD3+ is sourced from the original manufacturer or authorized distributors?

All MAX6729KAWGD3+ 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 MAX6729KAWGD3+ meets industry standards.

7.What is the process for return or replacement of MAX6729KAWGD3+?

All MAX6729KAWGD3+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX6729KAWGD3+, 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 MAX6729KAWGD3+ part is unused and in its original packaging.

Return procedure for MAX6729KAWGD3+:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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