Analog Devices Inc./Maxim Integrated MAX6726KASDD3+T

Overview

MAX6726KASDD3+T 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 rails for telecom and industrial controllers.

For engineers reviewing the MAX6726KASDD3+T datasheet, MAX6726KASDD3+T pinout, MAX6726KASDD3+T application, or MAX6726KASDD3+T equivalent, this page delivers verified electrical parameters, confirmed dual-reset output logic, factory-trimmed dual-threshold voltages, watchdog timing behavior, and real-world use cases in battery-backed systems and FPGA power sequencing.

Technical Context

The MAX6726KASDD3+T integrates three independent voltage monitors: primary supply (VCC1) with 4.625V ±125mV factory-trimmed threshold, secondary supply (VCC2) at 3.075V ±75mV, and RSTIN referenced to a 626.5mV internal bandgap. Reset assertion is guaranteed down to VCC1 or VCC2 = 0.8V, with 20µs typical VCC-to-RST delay and 22µs RSTIN-to-RST delay.

It features dual-mode watchdog logic-35s minimum startup timeout after any reset event, followed by 1.12s minimum normal timeout-and supports manual reset via MR (50kΩ internal pullup, 1µs min pulse width). The device uses BiCMOS process (1072 transistors) and delivers 14µA typical supply current at 3.6V.

Key Specifications

Pinout & Package

MAX6726KASDD3+T is housed in an 8-pin SOT23-8 package (2.0mm × 2.1mm × 1.25mm, 0.65mm pitch), thermally optimized for high-density PCB layouts and compatible with standard reflow profiles.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microprocessor supervisory applications.

Compared with MAX6726KASDD3+T, MAX6725KAUDD3+T offers identical voltage monitoring and timing but omits PFO and uses open-drain outputs, while TPS3808G33DBVR reduces supply current by 82% but sacrifices triple-monitoring and power-fail alerting-making MAX6726KASDD3+T optimal for complex multirail systems requiring coordinated reset and early fault signaling.

Availability

MAX6726KASDD3+T is available at Aetrix Electronics and suitable for industrial PLC power sequencing, telecom line card supervision, portable medical monitor battery backup, and FPGA-based test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6726KASDD3+T 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 design leader specializing in precision analog, mixed-signal, and power management ICs for industrial, automotive, and communications markets.

The MAX6715–MAX6729 family was engineered to replace discrete reset circuits in multivoltage embedded systems, delivering integrated dual/triple monitoring, watchdog supervision, and power-fail detection in ultra-small SOT23 packages.

FAQ

What is the exact reset threshold voltage for VCC1 and VCC2 on the MAX6726KASDD3+T?

The MAX6726KASDD3+T has factory-trimmed reset thresholds of 4.625V (±125mV) for VCC1 and 3.075V (±75mV) for VCC2, as defined by the "AS" suffix per Maxim's Reset Voltage Threshold Suffix Guide. These values are measured under standard conditions (TA = +25°C, VCC1/VCC2 ≥ 0.8V) and remain stable across the full -40°C to +85°C operating range with 20ppm/°C tempco.

Does the MAX6726KASDD3+T support both active-high and active-low reset outputs simultaneously?

Yes, the MAX6726KASDD3+T provides simultaneous push-pull active-high RST (Pin 1) and active-low RST (Pin 8), both referenced to VCC1. This dual-output architecture eliminates external inverters or level shifters in systems requiring reset signals for both CMOS and TTL logic families, and is confirmed in the Pin Description table and Functional Diagram of the official datasheet.

How does the watchdog timer behave during system power-up on the MAX6726KASDD3+T?

The MAX6726KASDD3+T implements a dual-mode watchdog: after any reset event-including power-up-it enters a 35s minimum startup timeout period, allowing ample time for firmware initialization. Once the first valid WDI edge occurs, it transitions to the 1.12s minimum normal timeout mode. This behavior is explicitly documented in the Watchdog Input section and Figure 2 of the datasheet.

Can the RSTIN pin on the MAX6726KASDD3+T be used to monitor a negative supply voltage?

No-the RSTIN pin is designed for positive-supply monitoring only, with a fixed 626.5mV internal reference. To monitor negative rails, the MAX6726KASDD3+T's PFI pin must be used instead, configured with an external resistor network as shown in Figure 3a/b of the datasheet; RSTIN lacks the required input structure for negative-voltage sensing.

What is the maximum supply voltage the MAX6726KASDD3+T can tolerate on VCC1 and VCC2 pins?

The MAX6726KASDD3+T supports absolute maximum supply voltages of +6V on both VCC1 and VCC2 pins, as specified in the Absolute Maximum Ratings table. However, functional operation is guaranteed only within 0.8V to 5.5V per the Electrical Characteristics section, and exceeding 5.5V risks permanent damage despite the 6V absolute rating.