Analog Devices Inc./Maxim Integrated MAX6385XS21D3-T

Overview

MAX6385XS21D3-T from Maxim Integrated is a low-power microprocessor supervisory circuit with active-high push-pull reset output, factory-set 2.10V reset threshold (±2.5% over -40°C to +125°C), 140ms minimum VCC reset timeout, and debounced manual reset input (MR). It operates from 1.0V to 5.5V supply, draws only 3μA at 1.8V, and guarantees valid reset state down to VCC = 1V - used in portable battery-powered equipment for reliable power-up/brownout protection.

For engineers reviewing the MAX6385XS21D3-T datasheet, MAX6385XS21D3-T pinout, MAX6385XS21D3-T application, or MAX6385XS21D3-T equivalent, key selection factors include its 2.10V threshold accuracy, 140ms reset timeout, MR input with internal 63kΩ pullup, 4-pin SC70 package, and compatibility with dual-voltage monitoring systems requiring deterministic reset assertion during supply transients.

Technical Context

The MAX6385XS21D3-T integrates a precision voltage comparator with ±2.5% threshold accuracy over temperature and a monolithic timer that enforces a guaranteed minimum 140ms reset assertion after VCC rises above 2.10V. Its MR input features internal 63kΩ pullup and 1µs minimum pulse width support, enabling direct connection to momentary switches without external debounce.

Unlike open-drain variants, this device uses an active-high push-pull RESET output capable of sourcing 800µA at VCC ≥ 4.5V while maintaining VOH ≥ 0.8×VCC - eliminating need for external pullups and ensuring fast, rail-to-rail logic transitions critical in low-noise embedded control paths.

Key Specifications

Pinout & Package

MAX6385XS21D3-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 portable designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6385XS21D3-T, the MAX6385XS21D3+T offers identical performance with RoHS compliance, while TPS3808G12DBVR trades MR capability and precise 2.10V threshold for lower quiescent current and wider voltage range - making it suitable only for non-manual-reset applications where threshold tolerance permits.

Availability

MAX6385XS21D3-T is available at Aetrix Electronics and suitable for portable medical sensors, battery-powered IoT nodes, industrial PLC I/O modules, and dual-voltage microcontroller systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6385XS21D3-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, high-accuracy reset supervision for battery-critical and thermally harsh environments - specifically engineered for reliable microprocessor startup and brownout recovery in portable and embedded systems.

FAQ

What is the exact reset threshold voltage of MAX6385XS21D3-T and how stable is it over temperature?

The MAX6385XS21D3-T has a factory-set nominal reset threshold of 2.10V, with guaranteed accuracy of ±2.5% over the full operating temperature range of -40°C to +125°C. This stability is achieved through laser-trimmed on-chip references and BiCMOS process optimization - confirmed in the Electrical Characteristics table under "VCC Reset Threshold" with min/max limits of 2.05V to 2.15V at +25°C and 2.05V to 2.15V over temperature. The MAX6385XS21D3-T maintains this precision without external components.

Does MAX6385XS21D3-T support manual reset, and what are the electrical requirements for the MR pin?

Yes, MAX6385XS21D3-T includes a debounced manual reset input (MR) with an internal 63kΩ pullup resistor to VCC. To assert reset, drive MR below 0.3×VCC (for VTH < 4V) for ≥1µs; the device guarantees MR glitch rejection of 100ns. MR can be driven directly by CMOS/TTL logic or a momentary switch to GND - no external components required. The MAX6385XS21D3-T deasserts reset after MR returns high and the 140ms timeout expires.

What package type and dimensions does MAX6385XS21D3-T use, and is it RoHS-compliant?

MAX6385XS21D3-T uses a 4-pin SC70 package (outline number 21-0098, land pattern 90-0187), measuring 2.0mm × 2.1mm × 0.95mm. The "-T" suffix confirms it is lead(Pb)-free and RoHS-compliant per Maxim's ordering conventions. Thermal resistance is θJA = 322.6°C/W on a multilayer board. This compact footprint enables high-density layouts in wearables and handheld devices where space is constrained.

Can MAX6385XS21D3-T operate reliably at very low supply voltages, and what happens to the RESET output below 1.8V?

Yes, MAX6385XS21D3-T is fully specified down to VCC = 1.0V and guarantees valid RESET output logic states (VOH ≥ 0.8×VCC, VOL ≤ 0.3V) even at VCC = 1.0V. Below 1.8V, supply current increases only marginally (3μA at 1.8V → 4μA at 1.0V), and reset assertion remains deterministic. The MAX6385XS21D3-T ensures no metastability - RESET stays high during brownout and releases cleanly after 140ms once VCC exceeds 2.10V.

Is MAX6385XS21D3-T pin-compatible with older Maxim reset supervisors like MAX809 or MAX6326?

No, MAX6385XS21D3-T is not pin-compatible with MAX809 (3-pin SOT-23) or MAX6326 (3-pin SOT-23), as it uses a 4-pin SC70 package with dedicated MR and RESET pins. However, it is functionally and footprint-compatible within the MAX6384–MAX6390 family - e.g., MAX6385XS21D3+T shares identical pinout and electrical behavior. Pin compatibility across families requires matching package type, pin count, and signal assignment - which differs between SC70-4 and SOT-23-3 footprints.