Analog Devices Inc./Maxim Integrated MAX6865UK16D3L+T

Overview

The MAX6865UK16D3L+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 1.575V reset threshold, 300ms minimum reset timeout (D3), and 209s typical watchdog timeout (L suffix). It monitors VCC, responds to manual reset (MR) assertion, and triggers reset upon watchdog timer expiration - designed for reliable power-up/brownout protection in battery-critical systems.

For engineers reviewing the MAX6865UK16D3L+T datasheet, MAX6865UK16D3L+T pinout, MAX6865UK16D3L+T application, or MAX6865UK16D3L+T equivalent, this device delivers validated reset timing, guaranteed operation down to VCC = +1.1V, immunity to short VCC transients, and precise watchdog supervision for embedded µP systems requiring long battery life and fail-safe startup.

Technical Context

The MAX6865UK16D3L+T integrates voltage monitoring, a manual reset input (MR), and a watchdog timer with 209s typical timeout (L) into a single BiCMOS IC. Its reset output remains asserted for ≥300ms after VCC rises above 1.575V and MR deasserts, ensuring stable µP initialization.

Watchdog supervision operates via the WDI pin: any absence of edge transitions exceeding 209s (typ) triggers reset; the internal timer clears on rising/falling edges, MR assertion, or active reset. The device guarantees valid reset output down to VCC = +1.1V and exhibits <40µs immunity to 100mV VCC transients.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6865UK16D3L+T, MAX6864UK16D3L+T offers identical supervision functionality but inverted reset polarity, while TPS3836K33DBVR provides lower-cost basic reset without watchdog capability or nanopower efficiency - making MAX6865UK16D3L+T uniquely suited for long-life, safety-critical, watchdog-dependent designs.

Availability

MAX6865UK16D3L+T is available at Aetrix Electronics and suitable for portable medical devices, wearable health monitors, remote industrial loggers, and asset tracking units requiring stable component supply across extended product lifecycles.

Supply support for MAX6865UK16D3L+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 power management, sensing, and interface applications in industrial, medical, and communications markets.

The MAX6854–MAX6869 family delivers nanopower supervisory circuits optimized for battery longevity and robust reset reliability in space-constrained, low-voltage embedded systems - targeting applications where µP uptime and fail-safe boot are non-negotiable.

FAQ

What is the reset threshold voltage of the MAX6865UK16D3L+T?

The MAX6865UK16D3L+T has a factory-trimmed reset threshold voltage of +1.575V, with ±2.5% tolerance over the -40°C to +85°C operating temperature range. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix '16' corresponds to 1.575V. The device guarantees valid reset assertion down to VCC = +1.1V, making it suitable for ultra-low-voltage brownout detection in coin-cell-powered systems.

Does the MAX6865UK16D3L+T include a watchdog timer, and what is its timeout period?

Yes, the MAX6865UK16D3L+T includes a watchdog timer with a typical timeout period of 209 seconds, indicated by the 'L' suffix in the part number. This is verified in Table 3 (Watchdog Timeout) and the Ordering Information section. The timer resets on any rising or falling edge at the WDI pin and triggers reset if no transition occurs within the timeout window - enabling supervision of long-duration firmware routines without spurious resets.

What type of reset output does the MAX6865UK16D3L+T provide?

The MAX6865UK16D3L+T provides an active-high push-pull reset output on Pin 1. As documented in the MAX6864/MAX6865/MAX6866 Pin Description table, the MAX6865 variant outputs RESET high during reset assertion and references the signal to VCC. This eliminates the need for an external pullup resistor and simplifies interface to microprocessors requiring high-active reset inputs, unlike open-drain or active-low variants in the same family.

What is the minimum reset timeout period for the MAX6865UK16D3L+T?

The MAX6865UK16D3L+T has a minimum reset timeout period of 300ms, specified by the 'D3' suffix in the part number. This is confirmed in Table 4 (Reset Timeout Periods), where D3 corresponds to 150ms/225ms/300ms (min/typ/max). The 300ms hold time ensures sufficient duration for complete microprocessor initialization, including PLL lock, memory self-test, and peripheral configuration in resource-constrained embedded systems.

How does the MAX6865UK16D3L+T handle short VCC transients?

The MAX6865UK16D3L+T is immune to short VCC transients up to 40µs in duration when the overdrive is 100mV, as shown in the "Maximum VCC Transient Duration vs. Reset Threshold Overdrive" graph (Figure MAX684 toc05). This transient immunity prevents false resets in electrically noisy environments such as portable medical devices with motorized components or RF modules, ensuring supervision reliability without requiring additional filtering circuitry.