Analog Devices Inc./Maxim Integrated MAX6387XS46D3+T

Overview

MAX6387XS46D3+T from Maxim Integrated is a dual-voltage microprocessor supervisory circuit with active-low push-pull reset output, 4.63V factory-set VCC reset threshold, and 140ms minimum reset timeout period. It monitors both VCC and an auxiliary voltage via RESET IN pin and operates down to VCC = 1.0V, consuming only 3μA at +1.8V. It is used in battery-powered embedded systems requiring reliable power-up sequencing and brownout protection.

For engineers reviewing the MAX6387XS46D3+T datasheet, MAX6387XS46D3+T pinout, MAX6387XS46D3+T application, or MAX6387XS46D3+T equivalent, key selection criteria include dual-supply monitoring capability, ±2.5% reset threshold accuracy over –40°C to +125°C, guaranteed reset assertion down to VCC = 1V, and compatibility with SC70-4 packaging for space-constrained designs.

Technical Context

The MAX6387XS46D3+T integrates two independent reset comparators: one fixed at 4.63V for VCC monitoring and another referenced to an internal 1.27V bandgap for external resistor-divider–based auxiliary voltage detection (RESET IN). Its reset timeout is generated by a precision on-chip timer, not RC-based, ensuring stable 140ms delay across temperature and supply.

This device uses BiCMOS process technology to achieve ultra-low quiescent current (3μA at 1.8V) while maintaining robust noise immunity against negative-going VCC transients - up to 35µs at 100mV overdrive - and guarantees valid reset logic state even as VCC drops to 1.0V.

Key Specifications

Pinout & Package

MAX6387XS46D3+T is housed in a RoHS-compliant 4-pin SC70 package (outline 21-0098), measuring 2.0mm × 2.1mm × 0.95mm, with 0.65mm lead pitch and thermal resistance θ_JA = 322.6°C/W on multilayer board.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6387LT46D3+T, the MAX6387XS46D3+T offers identical functionality in a smaller 4-pin SC70 footprint ideal for compact designs, while TPS3808G33DBVR provides lower-cost single-supply supervision but omits the critical RESET IN feature required for dual-rail fault detection.

Availability

MAX6387XS46D3+T is available at Aetrix Electronics and suitable for battery-powered equipment, dual-voltage systems, and industrial controllers requiring stable component supply with guaranteed long-term availability.

Supply support for MAX6387XS46D3+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, with emphasis on low-power, high-reliability solutions.

The MAX6381–MAX6390 family was engineered specifically for microprocessor reset supervision in space- and power-constrained environments, delivering factory-trimmed accuracy, dual-supply monitoring, and ultra-low quiescent current in miniature packages.

FAQ

What is the exact reset threshold voltage of MAX6387XS46D3+T and how is it specified?

The MAX6387XS46D3+T has a factory-set VCC reset threshold of 4.63V nominal, with guaranteed tolerance of ±2.5% over the full operating temperature range (–40°C to +125°C). This value is defined in the Reset Thresholds table of the datasheet, where suffix "46" corresponds to VTH(min) = 4.51V, VTH(nom) = 4.63V, and VTH(max) = 4.74V at +25°C, and ±2.5% applies across temperature. The MAX6387XS46D3+T uses this fixed threshold to monitor the main supply rail.

Does MAX6387XS46D3+T support monitoring of a second voltage, and how is it implemented?

Yes, MAX6387XS46D3+T supports auxiliary voltage monitoring via the RESET IN pin, which connects to an internal comparator referenced to a precise 1.27V bandgap. To set a custom threshold, apply the external voltage through a resistor divider such that V_IN = 1.27V × (R1/R2 + 1); typical R2 values range from 10kΩ to 100kΩ. The MAX6387XS46D3+T asserts reset if either VCC falls below 4.63V or RESET IN falls below 1.27V.

What is the reset output configuration of MAX6387XS46D3+T and what are its drive capabilities?

The MAX6387XS46D3+T features an active-low push-pull reset output, meaning it actively drives LOW during reset and HIGH otherwise - no external pullup is required. It guarantees VOL ≤ 0.3V at ISINK = 1.2mA (VCC ≥ 2.5V) and VOH ≥ 0.8×VCC at ISOURCE = 500µA (VCC ≥ 2.5V). This output remains valid down to VCC = 1.0V, ensuring reliable reset signaling during deep brownout conditions.

What is the guaranteed reset timeout period for MAX6387XS46D3+T and how is it ensured across conditions?

The MAX6387XS46D3+T provides a guaranteed minimum reset timeout period of 140ms after VCC or RESET IN rises above their respective thresholds. This timing is generated by an on-chip precision oscillator-based timer, not an RC network, resulting in ±20% variation over temperature and supply - significantly tighter than discrete alternatives. The "D3" suffix in MAX6387XS46D3+T explicitly denotes this 140ms timeout option per the Reset Timeout Delay table.

Is MAX6387XS46D3+T qualified for automotive applications, and what package options support that grade?

The MAX6387XS46D3+T itself is not automotive-qualified; it carries the "+T" RoHS suffix but lacks the "/V" automotive trim designation. For AEC-Q100 qualification, select variants such as MAX6387XS46D3/V+T (4-pin SC70) or MAX6387LT46D3/V+T (6-pin µDFN), which undergo extended temperature stress testing and include automotive-specific screening. The MAX6387XS46D3+T is rated for –40°C to +125°C operation but is intended for industrial and commercial use unless explicitly ordered with /V suffix.