Analog Devices Inc./Maxim Integrated MAX6387XS23D3

Overview

MAX6387XS23D3 from Maxim Integrated is a low-power microprocessor supervisory circuit with dual-voltage monitoring capability, factory-set 2.31V VCC reset threshold (±2.5% over -40°C to +125°C), 140ms minimum reset timeout, and auxiliary RESET IN input for secondary voltage supervision. It features active-low push-pull RESET output, operates down to VCC = 1.0V, and consumes only 3µA at +1.8V - ideal for battery-powered IoT sensors and portable medical devices requiring reliable brownout protection.

For engineers reviewing the MAX6387XS23D3 datasheet, MAX6387XS23D3 pinout, MAX6387XS23D3 application, or MAX6387XS23D3 equivalent, key selection considerations include its dual-monitoring architecture, SC70-4 package footprint, guaranteed reset validity below 1V supply, ±2.5% threshold accuracy across automotive temperature range, and compatibility with resistor-divider-based external threshold configuration via RESET IN.

Technical Context

The MAX6387XS23D3 integrates two independent reset comparators: one monitors VCC against a factory-trimmed 2.31V threshold, while the second compares an external voltage applied to RESET IN against a precise +1.27V internal reference. Reset assertion occurs if either monitored voltage falls below its respective threshold, and the active-low push-pull output remains asserted for ≥140ms after recovery.

Its BiCMOS process enables ultra-low quiescent current (3µA at 1.8V) while maintaining robust noise immunity - including negative-going VCC transient rejection up to 35µs at 100mV overdrive - and guarantees valid logic states down to VCC = 1.0V without external biasing.

Key Specifications

Pinout & Package

MAX6387XS23D3 is housed in a lead-free 4-pin SC70 package (package code X4-1), measuring 2.0mm × 2.1mm × 0.95mm, with gull-wing leads optimized for high-density PCB layouts and automated assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6387LT23D3, the MAX6387XS23D3 offers smaller PCB area and faster assembly but slightly lower thermal margin; versus TPS3808G125DBVR, it delivers critical dual-rail supervision and push-pull drive at the cost of 1.2µA higher typical supply current.

Availability

MAX6387XS23D3 is available at Aetrix Electronics and suitable for battery-powered sensor nodes, automotive body control modules, industrial PLC I/O modules, and portable medical diagnostic devices requiring stable component supply with guaranteed long-term availability.

Supply support for MAX6387XS23D3 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 demanding industrial, automotive, and computing applications.

The MAX6381–MAX6390 family was engineered specifically for low-voltage, low-power microprocessor reset supervision in space-constrained and energy-sensitive systems - emphasizing factory-trimmed accuracy, dual-rail monitoring, and guaranteed operation down to 1.0V.

FAQ

What is the exact reset threshold voltage of MAX6387XS23D3 and how is it specified?

The MAX6387XS23D3 has a factory-set VCC reset threshold of 2.31V (nominal), with guaranteed tolerance of ±2.5% over the full operating temperature range (-40°C to +125°C). This value is laser-trimmed during production and documented in the Reset Thresholds table of the MAX6381–MAX6390 datasheet. The '23' suffix in MAX6387XS23D3 explicitly denotes this 2.31V threshold.

Does MAX6387XS23D3 support monitoring of a second voltage rail, and how is it implemented?

Yes, MAX6387XS23D3 supports dual-voltage monitoring via its dedicated RESET IN pin. This input compares an external voltage to an internal +1.27V reference; reset asserts if that voltage falls below the reference. Users configure the secondary threshold using a resistor divider - for example, connecting R1 and R2 between VCC and GND with RESET IN at their junction - enabling supervision of I/O, core, or analog rails independent of the main VCC threshold.

What is the function of the RESET output on MAX6387XS23D3, and what drive capability does it provide?

The RESET output of MAX6387XS23D3 is an active-low push-pull driver, meaning it actively pulls the line low during reset and actively drives it high when deasserted. It can sink up to 1.2mA at VCC ≥ 2.5V with VOL ≤ 0.3V, and source sufficient current to drive standard CMOS reset inputs without external components - eliminating the need for pull-up resistors required by open-drain alternatives like MAX6389.

How does the 140ms reset timeout period of MAX6387XS23D3 impact system reliability?

The 140ms minimum reset timeout period of MAX6387XS23D3 ensures the microcontroller remains held in reset long enough for all internal circuits - including PLLs, memory arrays, and I/O buffers - to stabilize after power recovery. This prevents erratic execution during marginal voltage conditions and aligns with common µP power-on reset requirements, especially in battery-powered systems where supply rise times may be slow due to high-impedance sources or large decoupling capacitance.

Can MAX6387XS23D3 operate reliably during severe VCC transients, and what protection does it offer?

Yes, MAX6387XS23D3 incorporates negative-going VCC transient immunity: it rejects short-duration supply glitches that fall below the reset threshold, provided the overdrive (VTH – VCC) and pulse width remain within defined limits. For example, at 100mV overdrive, it tolerates transients up to 35µs without asserting reset - a critical feature for automotive and industrial systems exposed to load dumps, relay switching noise, or ESD-induced supply disturbances.