Analog Devices Inc./Maxim Integrated MAX6726KALTD3+

Overview

MAX6726KALTD3+ 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 externally adjustable RSTIN input (626.5mV reference). It provides push-pull active-high RST and active-low RST outputs, manual reset input (MR), watchdog timer (1.12s normal / 35s startup timeout), and operates from -40°C to +85°C. It ensures reliable system reset in multivoltage embedded power management applications.

For engineers reviewing the MAX6726KALTD3+ datasheet, MAX6726KALTD3+ pinout, MAX6726KALTD3+ application, or MAX6726KALTD3+ equivalent, key selection criteria include dual reset output polarity, factory-trimmed dual-threshold supervision with auxiliary voltage monitoring capability, guaranteed reset validity down to VCC = 0.8V, low 14µA typical supply current, and integrated watchdog with long startup period for complex boot sequences.

Technical Context

The MAX6726KALTD3+ implements independent dual-threshold voltage comparators for VCC1 and VCC2, plus a high-impedance RSTIN comparator referenced to a 626.5mV internal bandgap. Reset assertion is triggered by any monitored supply falling below its threshold, MR activation, or watchdog timeout - with reset held for a minimum 210ms (D3 suffix) after recovery.

It integrates a dual-mode watchdog timer: 35s minimum initial timeout after power-up/manual reset, transitioning to 1.12s minimum normal timeout after first WDI edge detection. The device supports both push-pull RST (VCC1-referenced) and open-drain RST2 (VCC2-referenced), with internal 50kΩ MR pullup and 200ns MR-to-reset delay.

Key Specifications

Pinout & Package

MAX6726KALTD3+ is housed in an 8-pin SOT23-8 package (2.0mm × 2.1mm × 1.25mm), surface-mount, lead-free compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6726KALTD3+, MAX6725KAUTD3+ offers identical supervision accuracy and timing but replaces push-pull RST with open-drain for bus sharing, while TPS3808G33DBVR reduces functionality and current draw but omits critical triple-monitoring and watchdog features required for complex systems.

Availability

MAX6726KALTD3+ is available at Aetrix Electronics and suitable for industrial PLC power management, telecom line card supervision, medical imaging sensor modules, and automotive ADAS camera ECUs requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6726KALTD3+ 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 industrial, communications, and computing markets.

The MAX6715–MAX6729 family was designed to replace discrete reset circuits in multivoltage embedded systems, delivering compact, factory-trimmed supervision with configurable watchdog and power-fail functions in ultra-small SOT23 packages.

FAQ

What is the exact reset timeout period for MAX6726KALTD3+?

The MAX6726KALTD3+ has a minimum reset timeout period of 210ms, as 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 ensures sufficient hold time for microprocessor initialization before release from reset. The actual timeout may vary slightly due to process and temperature, but remains within specification limits defined in the datasheet.

Does MAX6726KALTD3+ support both active-high and active-low reset outputs?

Yes, MAX6726KALTD3+ provides both active-high RST (pin 1, push-pull) and active-low RST2 (pin 8, open-drain). The RST output is referenced to VCC1 and drives high during reset assertion; RST2 is referenced to VCC2 and pulls low. This dual-polarity capability eliminates external level shifters when interfacing with mixed-logic systems, and is confirmed in the Pin Description table and Selector Guide for MAX6726.

How is the third-supply monitoring implemented on MAX6726KALTD3+?

MAX6726KALTD3+ uses the RSTIN/PFI pin (pin 7) as an adjustable third-supply monitor with a precise 626.5mV internal reference. By connecting an external resistor divider between the target supply and ground, with the midpoint fed to RSTIN, the device triggers reset when the divided voltage falls below 626.5mV - enabling supervision of supplies as low as 0.62V. This function is explicitly documented in the Electrical Characteristics and Detailed Description sections.

What watchdog timeout modes does MAX6726KALTD3+ support?

MAX6726KALTD3+ implements a dual-mode watchdog timer: a 35s minimum initial timeout after power-up or manual reset, followed by a 1.12s minimum normal timeout after the first valid WDI transition. This architecture accommodates lengthy boot sequences while ensuring rapid response to runtime hangs. The behavior is confirmed in the Watchdog Input section and Figure 2 of the datasheet.

Is MAX6726KALTD3+ compatible with 1.8V-only systems?

MAX6726KALTD3+ supports VCC1 down to 1.8V and VCC2 down to 0.9V, but its factory-trimmed thresholds (4.625V and 3.075V) require VCC1 ≥ 4.625V and VCC2 ≥ 3.075V to supervise those rails. For true 1.8V-only systems, it can monitor lower supplies via RSTIN (e.g., 1.2V core using resistor divider), but cannot supervise VCC1/VCC2 themselves at 1.8V. This limitation is inherent to the selected threshold suffix "AL" per the Reset Voltage Threshold Suffix Guide.