Analog Devices Inc./Maxim Integrated MAX6387XS22D3+T

Overview

MAX6387XS22D3+T from Maxim Integrated is a dual-voltage microprocessor supervisory circuit with active-low push-pull reset output, 2.19V factory-set VCC reset threshold (±2.5% over -40°C to +125°C), 140ms minimum VCC reset timeout, and auxiliary RESET IN input for monitoring a second voltage source. It consumes only 3μA at +1.8V and guarantees valid reset state down to VCC = 1V, used in battery-powered dual-rail systems requiring reliable power-on reset and brownout protection.

For engineers reviewing the MAX6387XS22D3+T datasheet, MAX6387XS22D3+T pinout, MAX6387XS22D3+T application, or MAX6387XS22D3+T equivalent, key selection criteria include its 2.19V reset threshold accuracy, 140ms timeout timing, 4-pin SC70 package footprint, auxiliary voltage monitoring capability, and compatibility with low-voltage core/I/O rail supervision in portable and automotive-qualified designs.

Technical Context

The MAX6387XS22D3+T integrates two independent reset comparators: one monitors VCC against a precision 2.19V internal reference, while the second accepts an external voltage via RESET IN and compares it to a fixed +1.27V internal reference. Reset asserts when either monitored voltage falls below its respective threshold.

An internal timer ensures the active-low push-pull RESET output remains asserted for ≥140ms after VCC or RESET IN recovers above threshold. The device operates from 1.0V to 5.5V supply and maintains guaranteed logic-state validity of RESET down to VCC = 1V, enabling robust operation during deep brownout conditions.

Key Specifications

Pinout & Package

MAX6387XS22D3+T is housed in a RoHS-compliant 4-pin SC70 package (outline 21-0098, land pattern 90-0187), measuring 2.0mm × 2.1mm × 0.95mm, suitable for space-constrained portable PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6387XS22D3+T, the LT22D3+T variant offers identical functionality in a thermally superior μDFN package, while TLV803SDBZR provides a lower-cost, space-optimized alternative for single-rail applications lacking secondary voltage supervision needs.

Availability

MAX6387XS22D3+T is available at Aetrix Electronics and suitable for portable medical sensors, dual-rail industrial controllers, automotive body control modules, and battery-powered test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6387XS22D3+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 demanding industrial, automotive, and computing applications, with emphasis on low-power, high-reliability solutions.

The MAX6381–MAX6390 family delivers ultra-low-power microprocessor supervision for battery-critical and thermally harsh environments, specifically engineered for dual-voltage monitoring in portable, automotive, and industrial embedded systems.

FAQ

What is the exact reset threshold voltage of MAX6387XS22D3+T and how stable is it over temperature?

The MAX6387XS22D3+T has a factory-set VCC reset threshold of 2.19V, specified with ±2.5% tolerance over the full -40°C to +125°C operating range. This stability is achieved through laser-trimmed internal references and BiCMOS process design, making MAX6387XS22D3+T suitable for automotive and industrial applications where thermal drift must be tightly controlled without external calibration.

Does MAX6387XS22D3+T support monitoring of a second voltage rail, and how is it implemented?

Yes, MAX6387XS22D3+T includes a dedicated RESET IN pin that connects to an internal +1.27V comparator. To monitor a second voltage, apply the target rail to RESET IN through a resistor divider network calculated using R1 = R2 × [(V_INTH/1.27V) − 1]. This enables precise dual-rail supervision without adding discrete comparators, and MAX6387XS22D3+T asserts reset if either VCC or the divided RESET IN voltage falls below its respective threshold.

What is the function of the RESET output on MAX6387XS22D3+T and what load can it drive?

The RESET output of MAX6387XS22D3+T is an active-low push-pull driver capable of sinking 3.2mA at VCC ≥ 4.5V (V_OL ≤ 0.4V) and 1.2mA at VCC ≥ 2.5V (V_OL ≤ 0.3V). It directly interfaces with standard microprocessor reset inputs without requiring external pullup resistors, simplifying layout and reducing component count. MAX6387XS22D3+T guarantees correct logic state down to VCC = 1V, ensuring robust reset signaling during brownout.

How does the 140ms reset timeout period of MAX6387XS22D3+T benefit system reliability?

The 140ms minimum reset timeout period of MAX6387XS22D3+T ensures the microprocessor remains held in reset long enough to complete internal power stabilization, clock startup, and register initialization after VCC or RESET IN recovers above threshold. This prevents erratic boot behavior or firmware corruption caused by premature release, especially critical in systems with slow-ramping power supplies or complex clock trees. MAX6387XS22D3+T's guaranteed minimum timing eliminates reliance on external RC networks.

Is MAX6387XS22D3+T qualified for automotive applications, and what packaging supports this?

MAX6387XS22D3+T is not explicitly marked with /V suffix and therefore is not AEC-Q100 automotive-qualified per Maxim's ordering guide. For automotive use, select variants such as MAX6387XS22D3/V+T (4-pin SC70) or MAX6387LT22D3/V+T (6-pin μDFN), which undergo additional qualification testing. MAX6387XS22D3+T itself is rated for -40°C to +125°C operation and RoHS-compliant, but formal automotive qualification requires the /V suffix denoting certified production flow and test coverage.