Analog Devices Inc./Maxim Integrated MAX6381LT31D3+T

Overview

MAX6381LT31D3+T from Maxim Integrated is a low-power microprocessor supervisory circuit with factory-set 3.08V reset threshold, 140ms minimum VCC reset timeout, and active-low open-drain reset output. It monitors +1.8V to +5.0V supply rails, consumes only 3μA at +1.8V, guarantees valid reset state down to VCC = 1V, and operates across -40°C to +125°C for use in automotive and industrial power-up/brownout protection.

For engineers reviewing the MAX6381LT31D3+T datasheet, MAX6381LT31D3+T pinout, MAX6381LT31D3+T application, or MAX6381LT31D3+T equivalent, key selection criteria include its 3.08V ±2.5% threshold accuracy over temperature, 140ms reset timeout, open-drain output requiring external pullup, 6-pin μDFN package, and compatibility with dual-voltage monitoring systems where auxiliary reset input is not required.

Technical Context

The MAX6381LT31D3+T implements a precision voltage comparator with internal 1.27V reference for VCC monitoring and uses an RC-based timer to enforce a guaranteed minimum 140ms reset assertion after VCC exceeds the 3.08V threshold. Its open-drain RESET output requires an external pullup resistor and remains valid down to VCC = 1V, enabling reliable reset signaling during deep brownout conditions.

This device belongs to the MAX6381–MAX6390 family of single-supply supervisors with fixed thresholds and discrete timeout options; it lacks manual reset (MR) and auxiliary RESET IN inputs-distinguishing it from MAX6384–MAX6390 and MAX6387–MAX6389 variants-and is configured exclusively for primary VCC monitoring in space-constrained applications.

Key Specifications

Pinout & Package

MAX6381LT31D3+T is housed in a 6-pin μDFN package (Outline Number 21-0147, Land Pattern 90-0080) with wettable flanks, RoHS-compliant lead-free finish (+T suffix), and thermal resistance θ_JA = 477°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 MAX6381LT31D3+T, MAX6326LTR31D3+T simplifies BOM by removing the pullup resistor but sacrifices I/O voltage flexibility, while TLV809K31DBZR reduces size and static current at the expense of temperature range and automotive compliance-making MAX6381LT31D3+T optimal for space-constrained, high-reliability 1.8V–5.0V systems needing open-drain interoperability.

Availability

MAX6381LT31D3+T is available at Aetrix Electronics and suitable for automotive engine control units, industrial PLC I/O modules, medical battery-backed monitors, and smart energy meter MCU subsystems requiring stable component supply with guaranteed AEC-Q100 compliance and long-term lifecycle support.

Supply support for MAX6381LT31D3+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 computing applications, with emphasis on reliability, low power, and integration.

The MAX6381–MAX6390 product line delivers single/dual low-voltage microprocessor reset circuits targeting space-constrained, high-temperature environments where deterministic power-up sequencing and brownout immunity are critical.

FAQ

What is the exact reset threshold voltage of MAX6381LT31D3+T and how accurate is it over temperature?

The MAX6381LT31D3+T has a factory-set nominal reset threshold of 3.08V, with ±2.5% accuracy guaranteed over the full operating temperature range of -40°C to +125°C. This specification is confirmed in the Electrical Characteristics table of the official datasheet, where VTH min/max values at temperature extremes are explicitly listed as 3.00V and 3.15V respectively.

Does MAX6381LT31D3+T include a manual reset input (MR) or auxiliary RESET IN pin?

No, MAX6381LT31D3+T does not include a manual reset input or auxiliary RESET IN pin. It is a basic single-supply supervisor variant within the MAX6381–MAX6390 family, featuring only VCC monitoring and open-drain RESET output. MR is present only on MAX6384–MAX6386 and MAX6390; RESET IN appears only on MAX6387–MAX6389.

What package type and dimensions does MAX6381LT31D3+T use, and is it RoHS-compliant?

MAX6381LT31D3+T uses a 6-pin μDFN package (2mm × 2mm body, 0.5mm pin pitch, Outline Number 21-0147). The "+T" suffix confirms it is lead(Pb)-free and RoHS-compliant. Thermal characteristics include θ_JA = 477°C/W and θ_JC = 122°C/W on a multilayer PCB, per JEDEC JESD51-7 test methodology.

Can MAX6381LT31D3+T operate reliably at VCC = 1.0V, and what happens to the RESET output below that?

Yes, MAX6381LT31D3+T guarantees correct RESET output logic state down to VCC = 1.0V. Below 1.0V, the device ceases to function predictably-the datasheet explicitly states operation is not specified below this limit, and no design assurance is provided for RESET behavior at sub-1V supply levels.

How does the 140ms reset timeout of MAX6381LT31D3+T compare to other timeout options in the MAX6381–MAX6390 family?

The "D3" suffix in MAX6381LT31D3+T specifies a 140ms minimum reset timeout period, one of seven discrete options ranging from 1ms (D1) to 1200ms (D7). This value is factory-programmed and non-adjustable; other members like MAX6381LT31D4+T offer 1120ms, while MAX6390 variants provide split timeouts (e.g., 1120ms VCC + 140ms MR).