Analog Devices Inc./Maxim Integrated MAX6865UK25D6L+T

Overview

The MAX6865UK25D6L+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 2.5V reset threshold (±2.5%), 1200ms minimum reset timeout, manual reset input (MR), and a 209s typical watchdog timeout (L-suffix). It monitors VCC in battery-powered systems and asserts an active-high push-pull RESET during brownout, MR assertion, or watchdog expiration.

For engineers reviewing the MAX6865UK25D6L+T datasheet, MAX6865UK25D6L+T pinout, MAX6865UK25D6L+T application, or MAX6865UK25D6L+T equivalent, this device serves as a low-power, single-supply voltage monitor with integrated watchdog timer and manual reset-critical for portable medical devices, wearables, and energy-harvesting systems where supply stability and firmware fault recovery are essential.

Technical Context

The MAX6865UK25D6L+T implements a precision bandgap-based voltage comparator for VCC monitoring, coupled with a digital watchdog timer that clears on any WDI edge and expires if WDI remains static beyond 209s (typ). Its reset logic combines asynchronous MR assertion with synchronous VCC threshold detection and fixed 1200ms timeout (D6 option).

It uses BiCMOS process technology to achieve guaranteed reset validity down to VCC = +1.1V and immunity to sub-40µs VCC transients at 100mV overdrive. The active-high push-pull RESET output is referenced to VCC and sinks up to 1.2mA at VCC ≥ 2.38V.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount. Compact 2.9mm × 1.6mm footprint with 0.95mm height, optimized for space-constrained portable designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK25D6L+T and TPS3837K25DBVR, the MAX6865UK25D6L+T uniquely delivers active-high push-pull RESET, 170nA supply current, and 209s watchdog timeout in one 5-pin SOT23 package - enabling simpler, lower-power, and safer reset architecture for portable medical and industrial edge devices.

Availability

MAX6865UK25D6L+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign loggers, industrial wireless sensor nodes, and energy-harvesting remote controllers requiring stable component supply across extended product lifecycles.

Supply support for MAX6865UK25D6L+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, mixed-signal, and power management ICs for demanding industrial, medical, and communications applications.

The MAX6854–MAX6869 family was engineered specifically for ultra-low-power microprocessor supervision in battery-constrained portable equipment - delivering nanoscale current consumption without sacrificing reset accuracy or watchdog reliability.

FAQ

What is the exact reset threshold voltage of the MAX6865UK25D6L+T?

The MAX6865UK25D6L+T has a factory-trimmed reset threshold voltage of 2.5V with ±2.5% tolerance over temperature (–40°C to +85°C). This value is confirmed in the Threshold Suffix Guide (Table 2) where "25" corresponds to 2.5V nominal, and Electrical Characteristics specify VTH = 2.438V (min) to 2.563V (max) at TA = –40°C to +85°C. The MAX6865UK25D6L+T guarantees accurate brownout detection precisely at this 2.5V rail.

Does the MAX6865UK25D6L+T support active-high reset output?

Yes, the MAX6865UK25D6L+T features an active-high push-pull RESET output (Pin 1), as confirmed in the MAX6865-specific Pin Description (page 8) and Selector Guide (page 16). Unlike MAX6864 variants, the MAX6865UK25D6L+T asserts RESET high during fault conditions and deasserts it low after timeout - eliminating external level-shifting components when interfacing with µPs requiring active-high reset signals.

What is the watchdog timeout behavior of the MAX6865UK25D6L+T?

The MAX6865UK25D6L+T implements a watchdog timer with L-suffix configuration, providing a typical timeout of 209s (min 95s, max 487s). It clears on any rising or falling edge at WDI (Pin 4) and expires only if WDI remains static beyond that period. The MAX6865UK25D6L+T asserts RESET high upon expiration, maintaining it for the full 1200ms D6 timeout - ensuring robust firmware hang detection in long-cycle embedded applications.

Can the MAX6865UK25D6L+T operate down to 1.2V supply voltage?

Yes, the MAX6865UK25D6L+T operates across VCC = 1.2V to 5.5V, with guaranteed reset functionality valid down to VCC = +1.1V per Absolute Maximum Ratings and Electrical Characteristics. At 1.2V, its 170nA typical supply current and 2.5V threshold detection remain functional - making the MAX6865UK25D6L+T suitable for single-cell lithium or alkaline systems where supply voltage decays below 2.0V during end-of-life.

How does the manual reset (MR) input function on the MAX6865UK25D6L+T?

The MR input (Pin 3) is an active-low, internally 10kΩ-pulled-up signal that initiates reset when driven low. Reset remains asserted while MR is low and continues for the full 1200ms D6 timeout after MR returns high. The MAX6865UK25D6L+T tolerates MR pulse widths as short as 1µs and rejects glitches under 200ns - enabling reliable pushbutton or logic-controlled reset without external debounce circuitry.