Analog Devices Inc./Maxim Integrated MAX6865UK26D2L+T

Overview

The MAX6865UK26D2L+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 2.625V reset threshold (suffix "26"), 40ms minimum reset timeout (suffix "D2"), and integrated watchdog timer with 209s typical timeout (suffix "L"). It monitors VCC, responds to manual reset (MR), and asserts reset on voltage drop, MR assertion, or watchdog expiration - used in battery-powered medical and portable electronics requiring guaranteed reset validity down to VCC = +1.1V.

For engineers reviewing the MAX6865UK26D2L+T datasheet, MAX6865UK26D2L+T pinout, MAX6865UK26D2L+T application, or MAX6865UK26D2L+T equivalent, key selection criteria include its active-high push-pull RESET output, watchdog input (WDI) compatibility with µP firmware supervision, 2.625V threshold tolerance (±2.5%), and immunity to sub-40µs VCC transients at 100mV overdrive - critical for low-power brownout resilience in glucose monitors and wearables.

Technical Context

This device implements a precision bandgap-based voltage monitor with 0.5%VTH hysteresis, a digital watchdog timer cleared by WDI edges (min pulse width 150ns), and a fixed 40ms internal reset timeout counter. Its MR input features 10kΩ internal pullup and 200ns glitch rejection, enabling direct switch connection without external debounce.

The active-high push-pull RESET output delivers VOH ≥ 0.8×VCC (ISOURCE = 500µA) and VOL ≤ 0.3V (ISINK = 1.2mA), ensuring robust logic-level compatibility across 1.2V–5.5V VCC operation. Reset remains valid down to VCC = +1.1V, and supply current stays stable across -40°C to +85°C ambient.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount, 2.9mm × 1.6mm footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6865UK26D2S+T, the L-suffix version offers 63× longer watchdog timeout - essential for infrequent-firmware-update medical devices - while both share identical reset behavior and ultra-low power. Against TPS3837K26DBVR, MAX6865UK26D2L+T delivers 10× lower ICC and integrated watchdog, but requires firmware adaptation for WDI handling.

Availability

MAX6865UK26D2L+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, wearable ECG sensors, and industrial handheld scanners requiring stable component supply with guaranteed long-term availability and lead-free compliance.

Supply support for MAX6865UK26D2L+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, sensing, and interface applications in industrial, medical, and communications markets.

The MAX6865UK26D2L+T belongs to the MAX68xx nanopower supervisory family, engineered specifically for battery-critical portable medical and diagnostic equipment requiring guaranteed reset validity, ultra-low ICC, and integrated watchdog supervision.

FAQ

What is the exact reset threshold voltage of the MAX6865UK26D2L+T?

The MAX6865UK26D2L+T has a factory-trimmed reset threshold of 2.625V, with ±2.5% tolerance over temperature (-40°C to +85°C). This value is defined by the "26" suffix per Maxim's Threshold Suffix Guide (Table 2), and is verified in the Electrical Characteristics table where VTH = 2.625V ±2.5% under VCC = 1.2V–5.5V conditions. The MAX6865UK26D2L+T guarantees this threshold remains stable across its full operating range.

Does the MAX6865UK26D2L+T support active-high or active-low reset output?

The MAX6865UK26D2L+T features an active-high push-pull RESET output, as confirmed by its pin description (Pin 1 = RESET, "Active-High Push-Pull") and Selector Guide entry. When asserted, RESET goes high; when deasserted, it returns low. This matches the MAX6865 variant (not MAX6864/MAX6866), and eliminates need for external pullup resistors - a key differentiator from open-drain alternatives. The MAX6865UK26D2L+T output drives VOH ≥ 0.8×VCC under load.

What is the watchdog timeout period for the MAX6865UK26D2L+T?

The MAX6865UK26D2L+T has a watchdog timeout period of 209s typical (95s min, 487s max), indicated by the "L" suffix in its part number. This is specified in Table 3 ("Watchdog Timeout") and confirmed in the Electrical Characteristics table under "Watchdog Timeout Period tWD". The timer resets on any rising or falling edge at WDI (Pin 4), and is disabled only when RESET is asserted - ensuring continuous supervision during normal operation of the MAX6865UK26D2L+T.

Can the MAX6865UK26D2L+T operate down to 1.2V supply voltage?

Yes, the MAX6865UK26D2L+T operates across VCC = 1.2V to 5.5V, as stated in the Absolute Maximum Ratings and Electrical Characteristics tables. Its supply current remains ultra-low (170nA typ at 1.8V; 190nA typ at 1.2V), and reset functionality is guaranteed down to VCC = +1.1V - meaning the MAX6865UK26D2L+T continues asserting RESET correctly even as supply sags below 1.2V, critical for brownout recovery in low-voltage battery systems.

Is the MAX6865UK26D2L+T pin-compatible with other MAX68xx devices?

The MAX6865UK26D2L+T uses the standard 5-pin SOT23-5 package and shares identical pinout with MAX6864/MAX6866 variants: Pin 1 = RESET (active-high), Pin 2 = GND, Pin 3 = MR, Pin 4 = WDI, Pin 5 = VCC. However, it is not pin-compatible with MAX6861–MAX6863 (which use CT instead of WDI) or MAX6854–MAX6856 (which lack WDI). Pin compatibility applies only within the MAX6864/MAX6865/MAX6866 subgroup - confirmed in the Pin Configurations diagram and Selector Guide.