Analog Devices Inc./Maxim Integrated MAX6734KASHD3+T

Overview

MAX6734KASHD3+T from Maxim Integrated is a triple-voltage microprocessor supervisor IC with independent watchdog output, monitoring +3.075V (VCC1), +2.188V (VCC2), and an adjustable input down to +0.626V (RSTIN). It features open-drain RST and WDO outputs, manual reset input (MR), and a 210ms reset timeout period. Used in multivoltage embedded systems requiring reliable power-on reset and watchdog supervision during boot and runtime.

For engineers reviewing the MAX6734KASHD3+T datasheet, MAX6734KASHD3+T pinout, MAX6734KASHD3+T application, or MAX6734KASHD3+T equivalent, this page delivers verified electrical parameters, SOT23-8 pin mapping, real-world use cases in telecom and industrial equipment, and two validated alternative parts with documented functional and packaging differences.

Technical Context

The MAX6734KASHD3+T implements dual-mode watchdog logic: a 35s minimum startup delay after reset enables full system initialization, followed by a 1.12s minimum normal-mode timeout for rapid fault detection. Its triple-monitor architecture uses separate internal comparators for VCC1, VCC2, and RSTIN - the latter referenced to a precise 626mV bandgap threshold with ±3mV hysteresis and <100nA input current.

Reset assertion is guaranteed down to VCC1 or VCC2 = +0.8V, and the device maintains immunity to short VCC transients (e.g., ≤10µs at 75mV overdrive). All functions operate across –40°C to +125°C with supply current as low as 14µA typical at +3.6V.

Key Specifications

Pinout & Package

MAX6734KASHD3+T is housed in an 8-pin SOT23-8 package (Maxim package code K8S-3), measuring 3.00mm × 1.75mm × 1.30mm with gull-wing leads and JEDEC MO-178 compliance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6734KASHD3+T, MAX6734KASVD3+T changes only the VCC2 threshold - making it a direct substitution only in systems with matching secondary rail voltage. MAX6735KASHD3+T replaces open-drain outputs with push-pull, simplifying layout but requiring interface validation to prevent logic contention.

Availability

MAX6734KASHD3+T is available at Aetrix Electronics and suitable for telecom infrastructure, industrial PLCs, and automotive infotainment systems requiring stable component supply, extended temperature operation, and triple-rail supervision with integrated watchdog.

Supply support for MAX6734KASHD3+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, mixed-signal, and power management ICs for high-reliability applications in industrial, automotive, and communications markets.

The MAX6730A–MAX6735A family delivers integrated triple-voltage supervision with independent watchdog functionality - engineered specifically for space-constrained, multirail embedded systems needing deterministic reset behavior and robust fault detection.

FAQ

What is the exact reset threshold voltage for VCC1 and VCC2 on MAX6734KASHD3+T?

The MAX6734KASHD3+T has a VCC1 reset threshold of +3.075V (±1.5%) and a VCC2 reset threshold of +2.188V (±1.5%), as defined by the 'SH' suffix per Maxim's Reset Voltage Threshold Suffix Guide. These values are factory-trimmed and guaranteed over –40°C to +125°C. The MAX6734KASHD3+T uses these fixed thresholds to supervise primary and secondary supply rails independently.

Does MAX6734KASHD3+T support monitoring a third voltage higher than 0.626V?

Yes. The MAX6734KASHD3+T includes an RSTIN pin with a precise +626.5mV internal reference. To monitor voltages above this level - such as +5V or +12V - connect a resistive voltage divider between the target rail and RSTIN, sized so that the divided voltage equals 626.5mV at the trip point. The MAX6734KASHD3+T's high-impedance RSTIN input (<100nA leakage) ensures minimal loading on the divider network.

What is the function of the MR pin on MAX6734KASHD3+T, and how should it be used?

The MR (Manual Reset) pin on MAX6734KASHD3+T is an active-low input with an internal 50kΩ pullup to VCC1. Driving MR low forces RST low for the full reset timeout period (210ms), regardless of supply voltage status. It is commonly used with a momentary switch to GND for field service reset. The MAX6734KASHD3+T guarantees MR pulse rejection of 100ns glitches and accepts CMOS-level logic or open-drain signals.

How does the watchdog timer behave during power-up on MAX6734KASHD3+T?

The MAX6734KASHD3+T implements a dual-mode watchdog: after any reset event (power-up, brownout, or MR assertion), it enters a 35s minimum startup delay before enforcing the normal 1.12s timeout. This allows complex systems - such as those with multi-stage bootloaders or FPGA configuration - time to initialize fully before watchdog supervision begins. The MAX6734KASHD3+T transitions to normal mode either after the 35s elapses or upon the first valid WDI edge.

Is MAX6734KASHD3+T compatible with bidirectional µP reset pins?

Yes, but only when using the open-drain RST output (as on MAX6734KASHD3+T). To avoid logic contention with bidirectional µP reset I/O, connect a 10kΩ series resistor between RST and the µP pin. This limits current during potential voltage conflicts while preserving signal integrity. The MAX6734KASHD3+T's guaranteed reset validity down to +0.8V ensures correct behavior even during marginal supply conditions.