Analog Devices Inc./Maxim Integrated MAX6725AKAVDD3+

Overview

MAX6725AKAVDD3+ from Maxim Integrated is a dual-voltage microprocessor supervisory circuit in 6-pin SOT23 package, monitoring VCC1 (4.625V threshold) and VCC2 (3.075V threshold) with 210ms reset timeout, push-pull active-low RST output, manual-reset input, and watchdog disable capability. It ensures reliable system reset during power-supply faults in battery-powered embedded controllers.

For engineers reviewing the MAX6725AKAVDD3+ datasheet, MAX6725AKAVDD3+ pinout, MAX6725AKAVDD3+ application, or MAX6725AKAVDD3+ equivalent, key selection factors include guaranteed reset validity down to VCC1/VCC2 = 0.8V, 14µA typical supply current at 3.6V, immunity to short VCC transients, and factory-trimmed dual-threshold supervision without external components.

Technical Context

The MAX6725AKAVDD3+ integrates two independent voltage comparators with factory-trimmed thresholds (VTH1 = 4.625V, VTH2 = 3.075V), a 210ms minimum reset timeout timer, and push-pull RST output referenced to VCC1. It supports manual reset via MR input with internal 50kΩ pullup and guarantees valid reset assertion even when VCC1 or VCC2 drops to 0.8V.

This variant lacks RSTIN, WDI, PFI, and PFO functions - confirmed by its suffix "KAVDD3+" mapping to MAX6725A series with dual-supply monitoring only. Its architecture omits watchdog and auxiliary voltage monitoring, distinguishing it from MAX6726A/MAX6727A variants.

Key Specifications

Pinout & Package

MAX6725AKAVDD3+ uses a 6-pin SOT23 package (JEDEC MO-178AA), 2.9mm × 1.6mm × 1.1mm body, 0.95mm pitch. Pin 1 is marked with dot; pin order follows standard SOT23 orientation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-voltage supervisory applications.

Compared with MAX6725AKAVDD3+, MAX6726AKAVDD3+ offers identical supervision timing and accuracy but requires redesign of reset signal path due to active-high output, while TPS3808G33DBVR reduces power consumption by 87% but sacrifices dual-supply fault detection capability entirely.

Availability

MAX6725AKAVDD3+ is available at Aetrix Electronics and suitable for industrial PLC controllers, automotive body control modules, and medical portable monitors requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6725AKAVDD3+ 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 demanding environments.

The MAX6715A–MAX6729A family delivers ultra-low-voltage µP supervision for space-constrained, battery-operated, and high-reliability systems requiring dual/three-rail monitoring with minimal external components.

FAQ

What is the exact reset threshold voltage for VCC1 on MAX6725AKAVDD3+?

The MAX6725AKAVDD3+ has a factory-trimmed VCC1 reset threshold of 4.625V, with ±125mV tolerance over temperature. This value is fixed by the "K" suffix in the part number and does not require external resistor configuration. The threshold is guaranteed to remain stable across the full -40°C to +125°C operating range, making MAX6725AKAVDD3+ suitable for applications monitoring nominal 5V rails where precise brownout detection is critical.

Does MAX6725AKAVDD3+ support watchdog functionality?

No, MAX6725AKAVDD3+ does not include watchdog functionality. Its part number suffix "KAVDD3+" maps to the MAX6725A variant, which is explicitly defined in the datasheet as a dual-supply supervisor without WDI (watchdog input) or associated timing circuitry. Watchdog capability is present only in MAX6721A–MAX6729A variants with "W" or "X" suffixes. For systems requiring watchdog monitoring, MAX6725AKAVDD3+ must be replaced with a compatible variant such as MAX6727AWAVDD3+.

What is the function of Pin 6 (NC) on MAX6725AKAVDD3+?

Pin 6 on MAX6725AKAVDD3+ is designated NC (No Connect) and is internally unconnected. It must not be used for signal routing or grounding in PCB layout. Maxim's datasheet specifies that this pin should remain floating or be tied to GND solely for mechanical stability - never to VCC or any active signal. Using Pin 6 as a signal terminal may cause undefined behavior or damage, as it has no internal bond wire or circuit connection in the MAX6725AKAVDD3+ die configuration.

Can MAX6725AKAVDD3+ monitor a 1.8V supply as VCC2?

No, MAX6725AKAVDD3+ cannot reliably monitor a 1.8V supply as VCC2. Its factory-trimmed VCC2 threshold is fixed at 3.075V, optimized for 3.3V rails. Attempting to apply 1.8V to VCC2 will result in continuous reset assertion because the input falls far below the 3.075V threshold. For 1.8V monitoring, a different variant such as MAX6720A (with VTH2 = 1.710V) or an externally adjustable supervisor like MAX6723A would be required. MAX6725AKAVDD3+ is strictly intended for 5V/3.3V dual-rail systems.

What is the maximum load current supported by the RST output of MAX6725AKAVDD3+?

The push-pull RST output of MAX6725AKAVDD3+ supports up to 3.2mA sink current at VCC1 ≥ 4.5V (VOL ≤ 0.4V), and up to 800µA source current (VOH ≥ 0.8 × VCC1). These values are specified in the Electrical Characteristics table and ensure direct interfacing with standard CMOS µP reset inputs without external buffering. Exceeding these limits risks violating VOL/VOH specifications and may cause unreliable reset signaling, especially under worst-case temperature and voltage conditions.