Analog Devices Inc./Maxim Integrated MAX6387XS44D3+T

Overview

MAX6387XS44D3+T from Maxim Integrated is a dual-voltage microprocessor supervisory circuit with active-low push-pull reset output, 4.38V 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 rail. It operates from +1.0V to +5.5V supply and consumes only 3μA at +1.8V, targeting power-critical embedded systems requiring reliable brownout detection and dual-rail supervision.

For engineers reviewing the MAX6387XS44D3+T datasheet, MAX6387XS44D3+T pinout, MAX6387XS44D3+T application, or MAX6387XS44D3+T equivalent, key selection considerations include its 4-pin SC70 package, guaranteed reset validity down to VCC = 1V, ±2.5% threshold accuracy across automotive temperature range, and dedicated auxiliary comparator input enabling flexible dual-supply monitoring without external components.

Technical Context

The MAX6387XS44D3+T integrates two independent reset comparators: one monitors VCC against a fixed 4.38V threshold, while the second compares an external voltage applied to RESET IN against an internal +1.27V reference. Reset asserts when either monitored voltage falls below its respective threshold, and remains asserted for 140ms after recovery.

Its push-pull active-low RESET output guarantees correct logic state down to VCC = 1V and supports direct interface with µP reset inputs without external pullup. The device features negative-going VCC transient immunity up to 100mV overdrive and includes built-in glitch rejection on RESET IN (4.5µs delay) and MR (200ns delay).

Key Specifications

Pinout & Package

MAX6387XS44D3+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 PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6387XS44D3+T, the LT44D3+T variant offers identical functionality in a larger μDFN package for improved thermal performance, while TLV809E43DBZR provides lower power consumption but sacrifices auxiliary rail monitoring-making MAX6387XS44D3+T optimal for dual-supply integrity assurance in compact, thermally constrained designs.

Availability

MAX6387XS44D3+T is available at Aetrix Electronics and suitable for industrial PLC power monitoring, automotive body control modules, medical wearable sensor hubs, and smart energy metering requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6387XS44D3+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.

The MAX6381–MAX6390 family delivers ultra-low-power, high-accuracy reset supervision for microprocessor-based systems where dual-rail monitoring, guaranteed reset validity at low VCC, and AEC-Q100 qualification are essential.

FAQ

What is the exact reset threshold voltage of MAX6387XS44D3+T and how stable is it over temperature?

The MAX6387XS44D3+T has a factory-set VCC reset threshold of 4.38V nominal, 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 optimization, ensuring consistent brownout detection across automotive and industrial environments without external calibration.

Does MAX6387XS44D3+T support monitoring of a second voltage rail, and how is it implemented?

Yes, MAX6387XS44D3+T includes a dedicated RESET IN pin that connects to an internal +1.27V comparator. To monitor a second rail, apply the target voltage to RESET IN through a resistor divider-using R1 = R2 × ((V_INTH/1.27V) – 1)-enabling precise user-defined thresholds for I/O, core, or auxiliary supplies without additional ICs.

What is the guaranteed reset timeout period for MAX6387XS44D3+T, and does it vary with supply voltage or temperature?

The MAX6387XS44D3+T guarantees a minimum reset timeout of 140ms after VCC or RESET IN recovers above threshold. This value is specified as a minimum and remains stable across –40°C to +125°C and +1.0V to +5.5V VCC, with typical variation less than ±5% per the normalized timeout vs. temperature curve in the datasheet.

Can MAX6387XS44D3+T operate reliably when VCC drops below 1.8V, and what is the lowest functional supply voltage?

Yes, MAX6387XS44D3+T is fully specified down to VCC = 1.0V. Its reset output remains guaranteed valid (correct logic state) at VCC ≥ 1V, and supply current drops to just 3μA at +1.8V-making it suitable for battery-depleted or ultra-low-voltage brownout scenarios where other supervisors fail to assert reset correctly.

Is MAX6387XS44D3+T pin-compatible with any legacy reset ICs, and which packages share footprint compatibility?

MAX6387XS44D3+T is pin-compatible with the MAX809/MAX810 series and MAX6326–MAX6348 family in the 4-pin SC70 package. Its pinout (VCC–RESET–RESET IN–GND) matches industry-standard 4-pin supervisory footprints, enabling drop-in replacement in existing designs without PCB revision-provided the auxiliary RESET IN function is utilized or left unconnected.