Analog Devices Inc./Maxim Integrated MAX6381XR39D2

Overview

MAX6381XR39D2 from Maxim Integrated is a low-power microprocessor supervisory circuit with factory-set 3.9V reset threshold, 140ms minimum reset timeout, active-low open-drain reset output, and guaranteed operation down to VCC = 1.0V. It monitors single supply voltage in battery-powered embedded systems and portable equipment requiring precise brownout detection and ultra-low quiescent current (3µA at 1.8V).

For engineers reviewing the MAX6381XR39D2 datasheet, MAX6381XR39D2 pinout, MAX6381XR39D2 application, or MAX6381XR39D2 equivalent, key selection criteria include reset threshold accuracy (±2.5% over –40°C to +125°C), negative-going VCC transient immunity, SC70-3 package compatibility, and open-drain output requiring external pull-up for µP reset assertion.

Technical Context

The MAX6381XR39D2 implements a precision bandgap-based reset comparator with ±2.5% threshold accuracy across –40°C to +125°C and 60ppm/°C tempco. Its internal timer generates a fixed 140ms minimum reset timeout after VCC rises above 3.9V, with power-down reset delay under 35µs.

This device uses BiCMOS process technology (647 transistors) and features an open-drain RESET output that remains valid down to VCC = 1.0V. It lacks manual reset (MR) and auxiliary RESET IN inputs-functions reserved for other members of the MAX6381–MAX6390 family.

Key Specifications

Pinout & Package

MAX6381XR39D2 is housed in a 3-pin SC70-3 package (package code X3-2), measuring 2.0mm × 2.1mm × 0.95mm, with lead-free finish. Pin 1 = VCC, Pin 2 = RESET (open-drain), Pin 3 = GND.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX809TRD2+T and TPS3808G33DBVR, the MAX6381XR39D2 provides exact 3.9V threshold matching 3.3V systems with 10% headroom, smallest SC70-3 footprint, and optimized 140ms timeout for fast-recovery power rails-making it ideal for space- and timing-critical embedded designs.

Availability

MAX6381XR39D2 is available at Aetrix Electronics and suitable for battery-powered medical sensors, industrial PLC I/O modules, smart energy meters, and automotive body control units requiring stable component supply and long-term lifecycle support.

Supply support for MAX6381XR39D2 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 industrial, automotive, communications, and computing applications.

The MAX6381–MAX6390 family delivers low-power, high-accuracy µP supervisory circuits targeting space-constrained, battery-sensitive systems where supply monitoring integrity and minimal quiescent current are critical.

FAQ

What is the reset threshold voltage of the MAX6381XR39D2?

The MAX6381XR39D2 has a factory-set nominal reset threshold of 3.90V, with ±2.5% accuracy over the full operating temperature range of –40°C to +125°C. This value is laser-trimmed during production and does not require external components. The MAX6381XR39D2 will assert its open-drain RESET output when VCC falls below this threshold and hold it asserted for at least 140ms after VCC rises above it.

Does the MAX6381XR39D2 include a manual reset input (MR)?

No, the MAX6381XR39D2 does not feature a manual reset input. MR functionality is present only in specific variants within the MAX6381–MAX6390 family-namely MAX6384, MAX6385, MAX6386, and MAX6390. The MAX6381XR39D2 is a minimal-feature variant with VCC monitoring only, using a 3-pin SC70 package where all pins are dedicated to VCC, RESET, and GND. Adding MR would require a 4-pin or 6-pin configuration.

What package type and dimensions does the MAX6381XR39D2 use?

The MAX6381XR39D2 is supplied in a 3-pin SC70-3 package (package code X3-2), with overall dimensions of 2.0mm × 2.1mm × 0.95mm and a lead-free finish. Pin 1 is VCC, Pin 2 is the active-low open-drain RESET output, and Pin 3 is GND. This ultra-compact footprint is optimized for high-density PCB layouts in portable and wearable electronics where board space is constrained.

Can the MAX6381XR39D2 operate reliably at VCC = 1.2V?

Yes, the MAX6381XR39D2 is fully specified to operate and guarantee correct RESET output logic state down to VCC = 1.0V. At 1.2V, it continues to monitor the supply and assert reset if VCC drops below 3.9V (though such a condition implies upstream regulation failure). Its internal comparator and timer remain functional, and the open-drain RESET output maintains valid low-state sinking capability-critical for fail-safe behavior in deep brownout scenarios.

What is the maximum recommended pull-up resistor value for the MAX6381XR39D2 RESET output?

For the MAX6381XR39D2's open-drain RESET output, the maximum recommended pull-up resistor is 100kΩ when interfacing with standard CMOS inputs (e.g., 3.3V µP reset pin), based on VOL ≤ 0.3V at ISINK = 80µA and VCC ≥ 1.0V. Lower values (e.g., 10kΩ) improve noise immunity and rise time but increase static current. The MAX6381XR39D2 datasheet confirms valid operation with pull-ups up to 1MΩ in low-speed applications, though 10kΩ–100kΩ is optimal for most embedded designs.