Analog Devices Inc./Maxim Integrated MAX6385XS31D3+

Overview

MAX6385XS31D3+ from Maxim Integrated is a low-power, active-high push-pull µP supervisory circuit with factory-set 3.08V reset threshold, 140ms minimum reset timeout, and manual reset input (MR). It monitors VCC in 1.8V–5.0V systems, consumes only 3µA at 1.8V, guarantees valid reset output down to VCC = 1V, and is used in portable battery-powered equipment requiring reliable power-on reset and brownout protection.

For engineers reviewing the MAX6385XS31D3+ datasheet, MAX6385XS31D3+ pinout, MAX6385XS31D3+ application, or MAX6385XS31D3+ equivalent, key selection considerations include its 3.08V ±2.5% threshold accuracy over –40°C to +125°C, SC70-4 package footprint, MR debounced internal pullup (63kΩ), and compatibility with systems needing active-high reset assertion during VCC drop or manual trigger.

Technical Context

The MAX6385XS31D3+ implements a precision bandgap-based voltage comparator with ±2.5% threshold accuracy across temperature, paired with a monolithic RC timer for deterministic 140ms reset timeout after VCC recovery. Its active-high push-pull RESET output drives high when VCC falls below 3.08V or MR is pulled low, remaining asserted for ≥140ms after VCC exceeds threshold or MR release.

It features a dedicated MR input with internal 63kΩ pullup to VCC, TTL/CMOS-compatible logic levels, 1µs minimum pulse width support, and 100ns glitch rejection - enabling robust manual reset without external debounce components. The device operates from 1.0V to 5.5V supply and maintains correct RESET state down to VCC = 1V.

Key Specifications

Pinout & Package

MAX6385XS31D3+ is housed in a lead-free 4-pin SC70 package (X4-1), measuring 1.5mm × 1.0mm × 0.8mm, with 0.65mm pitch and moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6385XS31D3+, the LT variant offers identical functionality in a thermally superior µDFN package, while the TPS3808G30DBVR trades higher timing margin and lower ICC for different pinout and no MR input - making MAX6385XS31D3+ optimal for compact, MR-enabled, SC70-constrained designs.

Availability

MAX6385XS31D3+ is available at Aetrix Electronics and suitable for portable medical sensors, industrial PLC I/O modules, smart energy meters, and automotive body control units requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.

Supply support for MAX6385XS31D3+ 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) is a U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, computing, and consumer markets.

The MAX6381–MAX6390 family was designed specifically for low-voltage, low-power microprocessor supervision in space- and energy-constrained applications - emphasizing ultra-low ICC, small SC70/µDFN packaging, and robust reset timing under thermal and supply stress.

FAQ

What is the exact reset threshold voltage of MAX6385XS31D3+ and how stable is it over temperature?

The MAX6385XS31D3+ has a factory-set reset threshold of 3.08V, with guaranteed accuracy of ±2.5% over the full operating temperature range of –40°C to +125°C. This stability is achieved using a precision bandgap reference and laser-trimmed resistors, ensuring consistent brownout detection without external calibration. The MAX6385XS31D3+ maintains this specification across all production lots and environmental conditions within its absolute maximum ratings.

Does MAX6385XS31D3+ require an external pullup resistor on the RESET pin?

No, MAX6385XS31D3+ does not require an external pullup resistor on the RESET pin because it features an active-high push-pull output stage. The internal driver actively pulls RESET high during assertion and low during deassertion, eliminating dependency on external components. This simplifies PCB layout and improves noise immunity compared to open-drain alternatives. The MAX6385XS31D3+ datasheet confirms VOH and VOL specifications under defined sink/source conditions.

What is the function and electrical behavior of the MR pin on MAX6385XS31D3+?

The MR (Manual Reset) pin on MAX6385XS31D3+ is an active-low input that forces a reset when pulled below 0.3×VCC. It includes an internal 63kΩ pullup resistor to VCC, allowing direct connection to a normally-open momentary switch tied to GND. The MAX6385XS31D3+ guarantees MR pulse recognition down to 1µs width and rejects glitches shorter than 100ns. Reset remains asserted for the full 140ms timeout after MR is released.

Can MAX6385XS31D3+ operate reliably when VCC drops below 1.8V?

Yes, MAX6385XS31D3+ is fully specified to operate down to VCC = 1.0V, with guaranteed valid RESET output state (correct logic level) throughout that range. At VCC = 1.0V, the device still asserts active-high RESET when VCC falls below 3.08V and maintains timing integrity. Its 3µA supply current at 1.8V scales predictably downward, and the internal comparator remains functional - enabling use in deep-brownout scenarios where other supervisors fail. This behavior is confirmed in the Electrical Characteristics table of the MAX6385XS31D3+ datasheet.

What package type and dimensions does MAX6385XS31D3+ use, and is it RoHS-compliant?

MAX6385XS31D3+ uses a lead-free 4-pin SC70 package (package code X4-1), with nominal dimensions of 1.5mm × 1.0mm × 0.8mm and 0.65mm pin pitch. It meets RoHS Directive 2011/65/EU and JEDEC J-STD-020 moisture sensitivity level 1. The "+" suffix in the part number explicitly denotes lead-free, halogen-free, and green-compliant construction per Maxim's standard packaging policy. Footprint and soldering recommendations are provided in Maxim's SC70 package outline document 21-0098.