Analog Devices Inc./Maxim Integrated MAX6734KASDD3+T

Overview

The MAX6734KASDD3+T from Maxim Integrated is a triple-voltage microprocessor supervisor IC with independent watchdog output, monitoring VCC1 (+3.075V threshold), VCC2 (+2.313V threshold), and an adjustable RSTIN input (626mV reference). It features open-drain RST and WDO outputs, manual reset input, 140ms–280ms reset timeout, and operates from -40°C to +85°C in SOT23-8 package. Used in multivoltage telecom and industrial systems for reliable power-on reset and lockup recovery.

For engineers reviewing the MAX6734KASDD3+T datasheet, MAX6734KASDD3+T pinout, MAX6734KASDD3+T application, or MAX6734KASDD3+T equivalent, key selection criteria include dual fixed-voltage thresholds (VCC1/VCC2), third adjustable supply monitoring via RSTIN, watchdog startup delay (35s min), low 14µA typical supply current, and AEC-Q100 qualification eligibility for automotive designs.

Technical Context

The MAX6734KASDD3+T implements three independent voltage monitors: two factory-set comparators (VCC1 = 3.075V, VCC2 = 2.313V) and one high-impedance adjustable comparator (RSTIN = 626mV ±15.5mV) supporting external resistor-divider scaling. Its reset logic asserts active-low RST when any monitored voltage falls below its threshold or MR is pulled low, holding RST low for the D3 timeout period (140–280ms).

The watchdog subsystem uses a dual-mode timer: 35s minimum startup delay after reset, then transitions to 1.12s minimum normal timeout upon first WDI edge detection. WDO is open-drain and asserts low on WDI stall or undervoltage conditions at VCC1/VCC2/RSTIN. MR includes internal 50kΩ pullup and supports noise-immune manual reset with <1µs pulse width tolerance.

Key Specifications

Pinout & Package

Package: SOT23-8 (8-pin, surface-mount, 2.9mm × 1.6mm footprint, 1.1mm height).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6734KASDD3+T, MAX6734KATGD3+T shifts fixed thresholds downward for ultra-low-voltage systems, while MAX6735KASDD3+T replaces open-drain outputs with push-pull drivers-altering interface compatibility but preserving identical supervision logic and timing behavior.

Availability

MAX6734KASDD3+T is available at Aetrix Electronics and suitable for telecom infrastructure, industrial PLCs, and automotive infotainment systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6734KASDD3+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) designs precision analog and mixed-signal ICs for power management, sensing, and interface applications in industrial, automotive, and communications markets.

The MAX6730–MAX6735 family delivers integrated triple-voltage supervision with independent watchdog functionality, targeting high-reliability embedded systems where deterministic reset behavior and lockup recovery are critical.

FAQ

What is the exact reset threshold voltage for VCC1 on the MAX6734KASDD3+T?

The MAX6734KASDD3+T has a factory-set VCC1 reset threshold of 3.075V (minimum 3.000V, maximum 3.150V) with ±0.5% hysteresis. This value corresponds to the "T" suffix in the part number's threshold code and is guaranteed over the full -40°C to +85°C operating range. The threshold is referenced to an internal bandgap and exhibits 20ppm/°C tempco.

Does the MAX6734KASDD3+T support monitoring a third voltage below 0.63V?

No, the MAX6734KASDD3+T does not support monitoring voltages below 0.63V. Its RSTIN input uses a fixed 626mV internal reference with ±15.5mV tolerance; the lowest detectable input is 611mV (typical), and the datasheet explicitly states monitoring "down to +0.63V". Voltages below this require external level-shifting circuitry not supported by the device.

What is the function of the WDI pin on the MAX6734KASDD3+T and how should it be driven?

The WDI (Watchdog Input) pin on the MAX6734KASDD3+T clears the watchdog timer on each rising or falling edge. It must be toggled within 1.12s (normal mode) or 35s (startup mode) to prevent WDO assertion. Drive WDI with CMOS/TTL logic levels; if unused, connect to GND via ≤100kΩ resistor to maintain watchdog enable. Leaving WDI floating may cause erratic timeout behavior.

Can the MAX6734KASDD3+T operate with VCC1 and VCC2 supplied from different voltage sources?

Yes, the MAX6734KASDD3+T is designed to monitor independent voltage rails: VCC1 and VCC2 can be sourced from separate regulators or power domains. The device guarantees valid reset operation as long as either supply remains ≥+0.8V, and both thresholds (3.075V and 2.313V) are independently referenced. No synchronization between the rails is required.

Is the MAX6734KASDD3+T qualified for automotive applications?

The MAX6734KASDD3+T itself is not AEC-Q100 qualified; however, the MAX6734KATGD3/V+T and MAX6734KALTD3/V+T variants are explicitly listed as AEC-Q100 qualified in the datasheet. The "/V" suffix denotes automotive qualification. For automotive use, select a /V-part number - the MAX6734KASDD3+T is rated for industrial (-40°C to +85°C) only.