Analog Devices Inc./Maxim Integrated MAX6387XS16D3+

Overview

MAX6387XS16D3+ from Maxim Integrated is a dual-voltage microprocessor supervisory circuit with active-low push-pull reset output, 1.58V factory-set VCC reset threshold, 140ms minimum reset timeout, and auxiliary RESET IN input for monitoring a second voltage. It operates from +1.0V to +5.5V, consumes only 3µA at +1.8V, and guarantees valid reset state down to VCC = 1V - used in battery-powered embedded controllers requiring reliable power-on reset and secondary supply monitoring.

For engineers reviewing the MAX6387XS16D3+ datasheet, MAX6387XS16D3+ pinout, MAX6387XS16D3+ application, or MAX6387XS16D3+ equivalent, key selection criteria include its dual-monitor capability (VCC + RESET IN), ±2.5% reset threshold accuracy over –40°C to +125°C, SC70-4 package footprint, 140ms VCC reset timeout, and compatibility with low-voltage core/I/O rail sequencing in portable instrumentation and industrial edge nodes.

Technical Context

The MAX6387XS16D3+ integrates two independent reset comparators: one monitors VCC against a fixed 1.58V threshold, while the second compares an external voltage at RESET IN to an internal +1.27V reference. Its reset assertion logic triggers on either comparator violation, with a guaranteed 140ms minimum timeout after recovery.

It uses BiCMOS process technology (647 transistors), supports operation down to VCC = 1.0V with valid logic-level reset output, and provides negative-going VCC transient immunity up to 35µs for 100mV overdrive - critical for noisy DC-DC converter outputs in compact power systems.

Key Specifications

Pinout & Package

MAX6387XS16D3+ is housed in a lead-free 4-pin SC70 package (X4-1, 1.0mm × 1.3mm × 0.9mm), optimized for high-density PCB layouts in space-constrained applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6387LT16D3+, the MAX6387XS16D3+ saves 0.3mm² PCB area and enables higher component density; versus TPS3808G16DBVR, it delivers unique dual-supply monitoring in a smaller footprint but trades off absolute threshold precision for functional versatility.

Availability

MAX6387XS16D3+ is available at Aetrix Electronics and suitable for battery-powered medical sensors, industrial PLC I/O modules, automotive body control units, and smart energy meters requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for MAX6387XS16D3+ 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 communications applications.

The MAX6381–MAX6390 family delivers ultra-low-power, high-accuracy supervisory circuits for microprocessor reset and dual-rail voltage monitoring in space- and power-constrained embedded systems.

FAQ

What is the exact reset threshold voltage of MAX6387XS16D3+ and how is it specified?

The MAX6387XS16D3+ has a factory-set VCC reset threshold of 1.58V, with ±2.5% accuracy guaranteed over the full operating temperature range of –40°C to +125°C. This value is fixed and non-adjustable; the "16" suffix in MAX6387XS16D3+ explicitly denotes the 1.58V threshold per Maxim's ordering guide. The RESET IN input uses a separate +1.27V internal reference, enabling user-defined thresholds via external resistors.

Does MAX6387XS16D3+ support monitoring of two independent power rails simultaneously?

Yes, MAX6387XS16D3+ supports true dual-rail supervision: VCC is monitored against its fixed 1.58V threshold, while the RESET IN pin compares an external voltage to an internal +1.27V reference. Reset asserts if either condition is violated. This eliminates the need for two separate supervisors in systems with core and I/O supplies, such as ARM-based controllers with split 1.8V/3.3V domains.

What is the function of the RESET output on MAX6387XS16D3+ and what drive capability does it provide?

The RESET output of MAX6387XS16D3+ is an active-low push-pull driver, meaning it actively pulls low during reset and actively drives high when deasserted - no external pull-up is required. It guarantees VOL ≤ 0.3V at VCC ≥ 1.0V with 80µA sink current, and VOH ≥ 0.8×VCC with 1µA source current, ensuring robust interfacing with standard CMOS µP RESET# inputs across its full supply range.

How does the 140ms reset timeout period of MAX6387XS16D3+ impact system design?

The 140ms minimum reset timeout of MAX6387XS16D3+ ensures the microprocessor remains held in reset long enough for power supplies to stabilize, clock oscillators to start, and internal registers to clear - meeting JEDEC JESD78 requirements for reliable boot. This fixed delay is internally generated and temperature-compensated, eliminating timing uncertainty from RC networks and simplifying layout in noise-sensitive environments.

Can MAX6387XS16D3+ operate reliably during deep brownout conditions?

Yes, MAX6387XS16D3+ guarantees correct reset output logic state down to VCC = 1.0V, enabling reliable operation during severe brownouts where supply drops below typical 1.2V LDO dropout. Its BiCMOS design maintains comparator accuracy and timer functionality even as VCC collapses, preventing spurious release of reset that could cause MCU malfunction or data corruption in safety-critical applications.