Analog Devices Inc./Maxim Integrated MAX6865UK37D6L+T

Overview

The MAX6865UK37D6L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, a factory-trimmed 3.7V reset threshold (±2.5%), and a 600ms–1200ms reset timeout period (D6 option). It integrates manual reset input (MR), watchdog timer with 209s typical timeout (L suffix), and push-pull active-high RESET output - designed for reliable power-on reset and brownout protection in battery-critical systems like glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK37D6L+T datasheet, MAX6865UK37D6L+T pinout, MAX6865UK37D6L+T application, or MAX6865UK37D6L+T equivalent, this device delivers verified low-current supervision with guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients, and no external components required - critical for space-constrained, long-life embedded designs.

Technical Context

The MAX6865UK37D6L+T implements a dual-trigger reset architecture: it asserts reset when VCC falls below 3.7V, when MR is pulled low, or when the watchdog input (WDI) remains static beyond 209s (typ). Its internal watchdog timer clears on any WDI edge, MR assertion, or active reset - ensuring robust detection of firmware hangs without false triggers.

This variant belongs to the MAX6864–MAX6869 series with active-high push-pull RESET, fixed D6 reset timeout (600–1200ms), L-suffix watchdog (95–487s), and 3.7V threshold (suffix "37"). It operates across –40°C to +85°C, draws ≤15µA during reset assertion, and maintains valid reset output down to VCC = 1.1V - enabling operation through deep brownout conditions.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free (indicated by "+T" suffix), footprint-compatible with industry-standard 5-pin SOT23 layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK37D6L+T, the MAX6865UK37D6L+T provides direct compatibility with active-high reset µPs; versus TPS3837K33DBVR, it delivers 10× lower supply current and integrated watchdog - essential for battery-powered medical and industrial wearables requiring long-term reliability.

Availability

MAX6865UK37D6L+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, industrial handheld scanners, and smart wearables requiring stable component supply with guaranteed long-term availability and lead-free compliance.

Supply support for MAX6865UK37D6L+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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, medical, and communications applications.

The MAX6865UK37D6L+T belongs to the MAX6864–MAX6869 nanopower supervisory family, engineered specifically for ultra-low-power, safety-critical embedded systems where extended battery life and deterministic reset behavior are mandatory.

FAQ

What is the exact reset threshold voltage of the MAX6865UK37D6L+T?

The MAX6865UK37D6L+T has a factory-trimmed reset threshold of 3.7V with ±2.5% tolerance (minimum 3.608V, typical 3.700V, maximum 3.793V), as defined by the "37" suffix in its part number per Maxim's Threshold Suffix Guide. This value is guaranteed over –40°C to +85°C and ensures reliable detection of brownout on 3.3V nominal rails.

Does the MAX6865UK37D6L+T require external components for basic operation?

No, the MAX6865UK37D6L+T requires no external components for core functionality: it includes an internal 10kΩ pullup on MR, precision voltage reference, and watchdog oscillator. A 0.1µF bypass capacitor on VCC is recommended per the datasheet for noise immunity, but is not strictly required for reset assertion timing.

How does the watchdog timer in the MAX6865UK37D6L+T respond to firmware activity?

The MAX6865UK37D6L+T watchdog timer (L-suffix, 209s typical timeout) clears on any rising or falling edge at the WDI pin. If WDI remains static (high or low) longer than the timeout, it triggers a reset pulse for the D6 period (600–1200ms). The timer pauses while reset is asserted and resumes counting immediately upon deassertion.

What is the minimum supply voltage at which the MAX6865UK37D6L+T guarantees valid reset output?

The MAX6865UK37D6L+T guarantees valid RESET output down to VCC = +1.1V across the full temperature range (–40°C to +85°C). Below this, sink/source capability degrades, but the device continues asserting reset until VCC drops below 1.2V (absolute minimum operating voltage).

Is the MAX6865UK37D6L+T pin-compatible with other devices in the MAX686x family?

Yes, the MAX6865UK37D6L+T shares the identical 5-pin SOT23-5 pinout with all MAX6864–MAX6869 variants, including MAX6864, MAX6866, MAX6867, MAX6868, and MAX6869. Pin 1 is RESET, Pin 2 is GND, Pin 3 is MR, Pin 4 is WDI, and Pin 5 is VCC - enabling drop-in replacement within the same functional configuration group.