Analog Devices Inc./Maxim Integrated MAX6865UK34D6L+T

Overview

The MAX6865UK34D6L+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 3.4V reset threshold (suffix '34'), 1200ms minimum reset timeout (suffix 'D6'), and 209s typical watchdog timeout (suffix 'L'). It integrates voltage monitoring, manual reset input (MR), and watchdog timer (WDI) to ensure reliable power-on reset and code-execution error recovery in battery-powered medical and portable electronics.

For engineers reviewing the MAX6865UK34D6L+T datasheet, MAX6865UK34D6L+T pinout, MAX6865UK34D6L+T application, or MAX6865UK34D6L+T equivalent, this device is selected for ultra-low-power systems requiring guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients, and dual-fault detection via both supply brownout and software hang conditions.

Technical Context

The MAX6865UK34D6L+T implements a precision bandgap-based voltage monitor with ±2.5% reset threshold accuracy over -40°C to +85°C, coupled with a digital watchdog timer that clears on any WDI edge and expires if WDI remains static beyond 209s (typ). Its internal 10kΩ MR pullup and glitch rejection (200ns) enable robust manual reset without external components.

This variant belongs to the MAX6864–MAX6869 series with active-high push-pull RESET output, confirmed by its 'UK' prefix and '65' suffix per Maxim's Selector Guide. It lacks CT pin functionality (no reset timeout select), distinguishing it from MAX6861–MAX6863, and uses dedicated WDI and MR inputs - not shared pins - for independent fault detection paths.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free (indicated by '+T' suffix), footprint-compatible with industry-standard 5-lead SOT packages.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK34D6S+T and TPS3836K33DBVR, the MAX6865UK34D6L+T uniquely delivers long-interval (209s) autonomous software supervision in the same ultra-low-current, space-constrained SOT23 package - eliminating design compromises between power budget and functional safety.

Availability

MAX6865UK34D6L+T is available at Aetrix Electronics and suitable for portable medical devices, wearable health monitors, and industrial handheld terminals requiring stable component supply with guaranteed long-term availability.

Supply support for MAX6865UK34D6L+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 demanding industrial and medical environments.

The MAX6864–MAX6869 product line targets ultra-low-power systems needing integrated voltage monitoring, manual reset, and long-duration watchdog supervision - specifically optimized for battery longevity and functional safety in portable diagnostics and wearables.

FAQ

What is the exact reset threshold voltage of the MAX6865UK34D6L+T?

The MAX6865UK34D6L+T has a factory-trimmed reset threshold voltage of 3.4V, with ±2.5% tolerance over the full -40°C to +85°C operating temperature range. This value is confirmed by the '34' suffix in the part number and specified in Table 2 of the datasheet. The threshold is referenced to the VCC supply and remains stable across voltage and temperature variations, enabling precise brownout detection for 3.3V systems.

Does the MAX6865UK34D6L+T support active-high or active-low reset output?

The MAX6865UK34D6L+T provides an active-high push-pull RESET output, as indicated by its '65' suffix in Maxim's Selector Guide and confirmed in the MAX6864/MAX6865/MAX6866 Pin Description section. When a fault occurs (VCC < 3.4V, MR low, or WDI timeout), RESET asserts high; it deasserts low after the 600ms minimum timeout period. This eliminates the need for external pullup resistors used with open-drain variants.

What is the watchdog timeout period for the MAX6865UK34D6L+T, and how is it triggered?

The MAX6865UK34D6L+T features a 209s typical watchdog timeout period (L suffix), with min/max values of 95s and 487s. It is triggered when the WDI input remains static (high or low) beyond this interval. The internal timer clears on every rising or falling edge at WDI, allowing flexible firmware integration - such as toggling WDI at task boundaries - to prevent false timeouts during normal operation.

Can the MAX6865UK34D6L+T operate down to 1.2V supply voltage?

Yes, the MAX6865UK34D6L+T operates across a VCC range of 1.2V to 5.5V and guarantees valid RESET assertion down to VCC = +1.1V, as stated in the Electrical Characteristics table. At 1.2V, supply current is 190nA (typ), and reset threshold accuracy remains within ±2.5%. This extended low-voltage capability supports deep brownout recovery in energy-harvesting and primary-cell applications.

Is the MAX6865UK34D6L+T pin-compatible with other devices in the MAX68xx family?

The MAX6865UK34D6L+T uses the standard 5-pin SOT23-5 package and shares identical pinout with MAX6864, MAX6866, MAX6867, MAX6868, and MAX6869 - all assigning RESET to pin 1, GND to pin 2, MR to pin 3, WDI to pin 4, and VCC to pin 5. However, it is not pin-compatible with MAX6861–MAX6863 (which use CT on pin 1) or MAX6854–MAX6856 (which lack WDI). Always verify function mapping per the Selector Guide.