Analog Devices Inc./Maxim Integrated MAX6385XS21D1-T

Overview

MAX6385XS21D1-T from Maxim Integrated is a push-pull active-high microprocessor supervisory circuit with factory-set 2.10V reset threshold, 1ms minimum reset timeout, and manual reset input (MR), designed for reliable power-on reset assertion in low-voltage embedded systems operating from +1.8V to +5.0V supply rails. It consumes only 3μA at +1.8V and guarantees valid reset output down to VCC = 1V.

For engineers reviewing the MAX6385XS21D1-T datasheet, MAX6385XS21D1-T pinout, MAX6385XS21D1-T application, or MAX6385XS21D1-T equivalent, key selection considerations include its 2.10V ±2.5% threshold accuracy over -40°C to +125°C, 4-pin SC70 package footprint, MR debounce capability, and compatibility with critical μP power-monitoring requirements in space-constrained portable designs.

Technical Context

The MAX6385XS21D1-T implements a precision voltage comparator monitoring VCC against a trimmed internal reference, asserting RESET high when VCC falls below 2.10V and holding it for ≥1ms after VCC recovers. Its MR input features an internal 63kΩ pullup and accepts TTL/CMOS logic levels to force reset on demand.

This device belongs to the MAX6384–MAX6390 family with 4-pin SC70 packaging, active-high push-pull output, and no auxiliary RESET IN function-distinguishing it from MAX6387–MAX6389 variants. It supports stable operation across automotive-grade temperature range (-40°C to +125°C) and meets AEC-Q100 qualification when ordered with /V suffix.

Key Specifications

Pinout & Package

MAX6385XS21D1-T is housed in a RoHS-compliant 4-pin SC70 package (outline 21-0098, land pattern 90-0187), offering compact footprint (1.3mm × 1.7mm) and thermal resistance θJA = 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 MAX6385XS21D1-T, the D2 variant trades shorter reset duration for greater noise margin during marginal supply conditions, while the MAX6384 variant maintains identical timing but demands hardware/firmware adaptation for active-low signaling - making MAX6385XS21D1-T optimal for new designs needing active-high simplicity and minimal timeout.

Availability

MAX6385XS21D1-T is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive body control units, portable medical sensors, and battery-powered IoT edge nodes requiring stable component supply with guaranteed long-term availability.

Supply support for MAX6385XS21D1-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 and mixed-signal ICs for demanding industrial, automotive, and communications applications.

The MAX6381–MAX6390 family delivers low-power, high-accuracy μP supervisory circuits optimized for space-constrained, battery-sensitive, and thermally harsh environments where reliable power-on reset is mission-critical.

FAQ

What is the exact reset threshold voltage of MAX6385XS21D1-T and how stable is it over temperature?

The MAX6385XS21D1-T has a factory-set reset threshold of 2.10V with ±2.5% accuracy over the full operating temperature range of -40°C to +125°C. This stability is achieved through laser-trimming of internal references and verified by design across process corners - ensuring consistent brownout detection in automotive and industrial applications without external calibration.

Does MAX6385XS21D1-T require an external pullup resistor on the RESET pin?

No, MAX6385XS21D1-T does not require an external pullup resistor because it features an active-high push-pull RESET output. The internal driver actively pulls RESET high during assertion and sinks current when deasserted - simplifying layout and reducing BOM count compared to open-drain alternatives like MAX6383.

Can MAX6385XS21D1-T operate reliably at VCC = 1.2V?

Yes, MAX6385XS21D1-T guarantees correct RESET output logic state down to VCC = 1.0V, including at 1.2V. Its internal comparator and output stage remain functional across the full 1.0V to 5.5V operating range, enabling use in deep-brownout scenarios where other supervisors may release reset prematurely.

What is the function and electrical behavior of the MR pin on MAX6385XS21D1-T?

The MR pin on MAX6385XS21D1-T is an active-low manual reset input with an internal 63kΩ pullup resistor to VCC. Driving MR below 0.3×VCC asserts RESET high for the full 1ms timeout period after release. It accepts standard TTL/CMOS logic levels and supports direct connection to a momentary switch without external components.

Is MAX6385XS21D1-T pin-compatible with older Maxim reset ICs like MAX809?

Yes, MAX6385XS21D1-T is pin-compatible with MAX809/MAX810 series in the same 4-pin SC70 package. Both share identical VCC, GND, RESET, and MR pin assignments and electrical characteristics - allowing drop-in replacement in legacy designs without PCB modification or firmware changes.