Analog Devices Inc./Maxim Integrated MAX6865UK27D5S+T

Overview

The MAX6865UK27D5S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 2.700V reset threshold (suffix '27'), 300ms minimum reset timeout (suffix 'D5'), and integrated watchdog timer with 3.3s typical timeout (suffix 'S'). It monitors VCC, responds to manual reset (MR), and asserts active-high push-pull RESET during brownout, power-up, or watchdog expiration - used in battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK27D5S+T datasheet, MAX6865UK27D5S+T pinout, MAX6865UK27D5S+T application, or MAX6865UK27D5S+T equivalent, key selection criteria include its 2.7V threshold accuracy over temperature, guaranteed RESET validity down to VCC = +1.1V, immunity to sub-40µs VCC transients, and compatibility with low-power µP reset inputs requiring active-high assertion.

Technical Context

The MAX6865UK27D5S+T implements a precision bandgap-based voltage monitor with ±2.5% threshold tolerance and 0.5% hysteresis, paired with a digitally controlled watchdog timer that clears on any WDI edge and expires after 3.3s (typ) if inactive. Its internal 10kΩ MR pullup and glitch rejection (200ns) enable direct switch interfacing without external components.

This device uses BiCMOS process technology (2848 transistors) to achieve nanoscale quiescent current while maintaining robust timing: VCC-to-RESET delay is 40µs (max), MR-to-RESET delay is 250ns (max), and reset timeout is guaranteed ≥300ms across -40°C to +85°C.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount, 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 MAX6864UK27D5S+T and TPS3836K27DBVR, the MAX6865UK27D5S+T uniquely delivers active-high RESET, nanoscale current, and integrated watchdog in one pinout - critical for space-constrained, long-life medical electronics where reset polarity and power budget are non-negotiable.

Availability

MAX6865UK27D5S+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered diagnostics equipment, and industrial handheld scanners requiring stable component supply across extended product lifecycles.

Supply support for MAX6865UK27D5S+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 demanding applications in industrial, medical, and communications markets.

The MAX6854–MAX6869 family was engineered specifically for ultra-low-power microprocessor supervision in battery-critical systems, emphasizing nanoscale ICC, wide VCC range, and integrated watchdog functionality without external components.

FAQ

What is the exact reset threshold voltage of the MAX6865UK27D5S+T?

The MAX6865UK27D5S+T has a factory-trimmed reset threshold of 2.700V with ±2.5% tolerance over -40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix '27' corresponds to 2.700V nominal. The device guarantees valid RESET assertion down to VCC = +1.1V, making it suitable for deep brownout detection in low-voltage systems.

Does the MAX6865UK27D5S+T require external components for basic operation?

No, the MAX6865UK27D5S+T operates autonomously with no external components required. It integrates a 10kΩ internal pullup on the MR pin, precision voltage reference, watchdog timer, and push-pull RESET driver. Only a 0.1µF ceramic bypass capacitor on VCC to GND is recommended for noise immunity - no resistors, capacitors, or level shifters are needed for standard use.

How does the watchdog timer in the MAX6865UK27D5S+T function?

The MAX6865UK27D5S+T watchdog timer expires after 3.3s (typical) if the WDI input remains static (high or low). It clears on any rising or falling edge at WDI, including pulses as short as 150ns. During RESET assertion, the timer halts; it resumes counting immediately upon RESET deassertion. This behavior prevents false timeouts during normal firmware execution while catching stuck loops.

What is the reset timeout period for the MAX6865UK27D5S+T, and is it adjustable?

The MAX6865UK27D5S+T has a fixed reset timeout period of 300ms (minimum), specified by suffix 'D5' per Table 4. This value is factory-programmed and not user-adjustable. Unlike MAX6861–MAX6863 variants, the MAX6865UK27D5S+T does not include a CT pin; its timeout is permanently set and guaranteed across temperature and voltage.

Is the MAX6865UK27D5S+T pin-compatible with other devices in the MAX68xx family?

Yes, the MAX6865UK27D5S+T shares the identical 5-pin SOT23-5 pinout with all MAX6854–MAX6869 variants, including MAX6864, MAX6866, and MAX6867. Pin 1 is RESET, Pin 2 is GND, Pin 3 is MR, Pin 4 is WDI, and Pin 5 is VCC. This allows drop-in replacement within the same functional configuration - e.g., swapping MAX6865 (active-high RESET) for MAX6864 (active-low) requires only µP reset pin compatibility verification.