Analog Devices Inc./Maxim Integrated MAX6386XS31D3-T

Overview

MAX6386XS31D3-T from Maxim Integrated is a low-power, open-drain active-low microprocessor supervisory circuit with factory-set 3.08V reset threshold, 140ms minimum VCC reset timeout, and debounced manual reset input (MR). It monitors +1.8V to +5.0V supply rails, consumes only 3μA at +1.8V, guarantees valid reset output down to VCC = 1V, and is qualified for automotive applications (-40°C to +125°C). It is used in battery-powered controllers and critical μP systems requiring reliable power-on reset and brownout protection.

For engineers reviewing the MAX6386XS31D3-T datasheet, MAX6386XS31D3-T pinout, MAX6386XS31D3-T application, or MAX6386XS31D3-T equivalent, key selection criteria include its 3.08V ±2.5% reset threshold accuracy over temperature, 140ms reset timeout, MR input with internal 63kΩ pullup, open-drain RESET output requiring external pullup, and 4-pin SC70 package compatibility with space-constrained embedded designs.

Technical Context

The MAX6386XS31D3-T implements a precision voltage comparator with ±2.5% threshold accuracy across -40°C to +125°C and a monolithic timer for fixed 140ms reset assertion after VCC recovery. Its open-drain RESET output supports wired-OR configurations and level-shifting, while the MR input accepts TTL/CMOS logic and features built-in debounce via internal RC filtering.

It operates with guaranteed functionality down to VCC = 1V, includes negative-going VCC transient immunity up to 100mV overdrive for ≤35µs, and uses BiCMOS process technology to achieve ultra-low quiescent current (3μA at +1.8V) without sacrificing noise rejection or timing stability.

Key Specifications

Pinout & Package

MAX6386XS31D3-T is housed in a RoHS-compliant 4-pin SC70 package (outline 21-0098, land pattern 90-0187), measuring 1.6mm × 1.6mm × 0.95mm, with 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 MAX6386XS31D3-T, MAX6326XR31D3+T offers identical timing and threshold but omits MR and uses push-pull output, while TPS3808G33DBVR shifts threshold upward by 220mV and doubles supply current-making MAX6386XS31D3-T optimal for MR-requiring, ultra-low-power, precise 3.08V monitoring.

Availability

MAX6386XS31D3-T is available at Aetrix Electronics and suitable for automotive body control modules, industrial PLCs, portable medical sensors, and smart metering systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6386XS31D3-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, mixed-signal, and power management ICs for demanding industrial, automotive, and computing applications.

The MAX6381–MAX6390 family delivers ultra-low-power, AEC-Q100–qualified supervisory circuits optimized for reliable reset generation in battery-constrained and thermally harsh environments.

FAQ

What is the exact reset threshold voltage of MAX6386XS31D3-T and how stable is it over temperature?

The MAX6386XS31D3-T has a factory-set reset threshold of 3.08V with ±2.5% accuracy over the full -40°C to +125°C operating range. This corresponds to a worst-case window of 2.998V to 3.162V. The threshold exhibits a tempco of 60ppm/°C, ensuring minimal drift across automotive thermal cycles. This specification is production-guaranteed, not just typical.

Does MAX6386XS31D3-T require an external pullup resistor on the RESET pin, and what value is recommended?

Yes, MAX6386XS31D3-T requires an external pullup resistor on the open-drain RESET pin because it cannot source current. A 10kΩ to 100kΩ resistor to the target logic supply (e.g., 3.3V or 5V) is recommended. Lower values improve noise immunity and rise time; higher values minimize standby current. The device's RESET output can sink 3.2mA at VCC ≥ 4.5V, supporting standard logic-level interfaces.

Can MAX6386XS31D3-T operate reliably when VCC drops below 1.8V, and down to what voltage does it guarantee correct reset behavior?

Yes, MAX6386XS31D3-T guarantees correct reset assertion and deassertion down to VCC = 1.0V. Its internal circuitry remains functional and the RESET output state is valid even at 1.0V, unlike many competitors that fail below 1.5V. This ensures safe processor hold-down during deep brownout conditions common in automotive stop-start systems and battery depletion scenarios.

What is the function and electrical behavior of the MR pin on MAX6386XS31D3-T?

The MR (Manual Reset) pin on MAX6386XS31D3-T is an active-low input with an internal 63kΩ pullup resistor to VCC. Driving MR to GND forces RESET low for the full 140ms timeout, even if VCC is nominal. MR accepts TTL/CMOS logic levels and rejects glitches <100ns. When unused, it may be left floating (due to internal pullup) or tied to VCC; no external components are required for basic operation.

Is MAX6386XS31D3-T pin-compatible with legacy Maxim reset ICs like MAX809, and what are the key mechanical differences?

MAX6386XS31D3-T is functionally compatible but not pin-compatible with MAX809. While both are 4-pin SC70 supervisory circuits, MAX809 uses a different pinout (VCC–GND–RESET–MR vs. VCC–RESET–MR–GND). MAX6386XS31D3-T follows the newer Maxim SC70 layout (pin 1=VCC, pin 2=RESET, pin 3=MR, pin 4=GND), requiring PCB redesign for drop-in replacement. Footprint dimensions (1.6mm × 1.6mm) match, but land pattern alignment differs.