Analog Devices Inc./Maxim Integrated MAX6739XKRD3+T

Overview

MAX6739XKRD3+T from Maxim Integrated is a dual-voltage microprocessor supervisor IC with one factory-trimmed reset threshold (VTH1 = 3.075V) and one adjustable reset input (RSTIN, 488mV internal reference), manual reset input (MR), open-drain RESET output, and SC70-5 package. It monitors primary supply VCC1 (1.0–5.5V) and secondary supply VCC2 (0.9–3.3V), asserts reset if either falls below threshold, and maintains reset for ≥150ms after recovery. Used in portable battery-powered systems requiring precise dual-rail power monitoring.

For engineers reviewing the MAX6739XKRD3+T datasheet, MAX6739XKRD3+T pinout, MAX6739XKRD3+T application, or MAX6739XKRD3+T equivalent, key selection criteria include its 3.075V/adjustable dual-threshold architecture, 6µA quiescent current, 150ms reset timeout, SC70-5 footprint, and MR-enabled field serviceability in space-constrained embedded designs.

Technical Context

The MAX6739XKRD3+T implements two independent voltage comparators: one for fixed VCC1 monitoring at 3.075V (±1.5% over -40°C to +85°C), and one for RSTIN using an internal 488mV reference with <10nA input leakage. Its reset logic combines ORed fault detection across VCC1, VCC2, and RSTIN inputs, with a monolithic 150ms timeout timer that restarts on any new fault event before timeout completion.

It features a dedicated active-low manual reset input (MR) with 1.5kΩ internal pullup to VCC1, 1µs minimum pulse width requirement, and 150ms MR timeout period. The open-drain RESET output requires external pullup and supports bidirectional µP reset I/O interfaces via series 4.7kΩ resistor per application note.

Key Specifications

Pinout & Package

MAX6739XKRD3+T is housed in a 5-pin SC70-5 package (1.6mm × 1.6mm × 0.9mm, 0.65mm pitch), optimized for high-density portable PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6738XKRD3+T and TPS3808G33DBVR, MAX6739XKRD3+T uniquely delivers factory-trimmed dual thresholds (3.075V/2.625V), adjustable RSTIN monitoring, and integrated MR pullup in the smallest SC70-5 footprint-enabling compact, feature-complete supervision without design compromises.

Availability

MAX6739XKRD3+T is available at Aetrix Electronics and suitable for portable medical sensors, notebook power management, industrial PLC I/O modules, and GPS tracking beacons requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6739XKRD3+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 company specializing in precision analog, mixed-signal, and power management ICs for industrial, communications, and consumer applications.

The MAX6736–MAX6745 product line was designed specifically for ultra-low-power dual- and triple-voltage microprocessor supervision in space-constrained portable and battery-operated equipment.

FAQ

What is the exact reset threshold voltage for VCC1 on MAX6739XKRD3+T?

The MAX6739XKRD3+T has a factory-trimmed VCC1 reset threshold of 3.075V, with ±1.5% tolerance over the full -40°C to +85°C operating temperature range. This value is confirmed in Table 1 of the datasheet under suffix "T", and applies specifically to the MAX6739 variant with RD suffix indicating VCC2 = 2.625V. The MAX6739XKRD3+T does not support user adjustment of VCC1 threshold.

Does MAX6739XKRD3+T support manual reset functionality, and how is it implemented?

Yes, MAX6739XKRD3+T includes a dedicated active-low manual reset (MR) input on Pin 3. It features an internal 1.5kΩ pullup resistor to VCC1, allowing direct connection of a momentary pushbutton switch between MR and GND. When pressed ≥1µs, MR forces RESET low and maintains it for 150ms after release. No external components are required for basic MR implementation.

What is the purpose of the RSTIN pin on MAX6739XKRD3+T, and what voltage range can it monitor?

The RSTIN pin (Pin 4) on MAX6739XKRD3+T provides an adjustable reset input with a precise 488mV internal reference. Using an external resistor divider, it can monitor supply voltages from 0.5V up to 5.5V. For example, a 100kΩ/10kΩ divider on a 5.5V rail sets trip point at 0.5V × (110k/10k) = 5.5V. Input leakage is <10nA, enabling high-resistance dividers to minimize power loss.

What package type and dimensions does MAX6739XKRD3+T use, and is it RoHS-compliant?

MAX6739XKRD3+T uses the SC70-5 package: 1.6mm × 1.6mm body size, 0.9mm maximum height, and 0.65mm lead pitch. It is RoHS-compliant and halogen-free, with lead-free terminations confirmed by the "+T" suffix in the part number. The SC70-5 footprint occupies ~60% less area than standard SOT23-5, critical for ultra-compact PCBs.

How does the reset timeout behavior work on MAX6739XKRD3+T when multiple supply faults occur?

MAX6739XKRD3+T uses restartable timeout logic: the 150ms reset timeout period begins when the first monitored supply (VCC1, VCC2, or RSTIN) falls below threshold, and resets to zero each time any monitored supply falls below its threshold before timeout completion. This ensures reset remains asserted throughout sustained or intermittent brownout conditions until all supplies remain above thresholds for a continuous 150ms window.