Analog Devices Inc./Maxim Integrated MAX6865UK27D1L+T

Overview

The MAX6865UK27D1L+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 2.7V reset threshold (±2.5%), 10ms minimum reset timeout, manual reset input (MR), and watchdog timer with 209s typical timeout. It monitors VCC in battery-powered systems to assert active-low push-pull RESET during brownout, power-up, or software fault conditions.

For engineers reviewing the MAX6865UK27D1L+T datasheet, MAX6865UK27D1L+T pinout, MAX6865UK27D1L+T application, or MAX6865UK27D1L+T equivalent, this device serves as a precision, low-quiescent-current reset and watchdog solution for portable medical, handheld, and ultra-low-power embedded systems where supply stability and code execution integrity are critical.

Technical Context

The MAX6865UK27D1L+T integrates a voltage monitor with hysteresis (0.5% of VTH), a watchdog timer that clears on any WDI edge and expires if WDI remains static >209s (typ), and a manual reset input with 250ns MR-to-RESET delay and 1µs minimum pulse width. Its internal 10kΩ MR pullup eliminates external components.

It guarantees valid RESET assertion down to VCC = +1.1V, features immunity to VCC transients ≤40µs at 100mV overdrive, and supports noise-immune operation via dedicated GND and internal logic thresholds referenced to VCC (VIH = 0.7×VCC, VIL = 0.3×VCC on MR/WDI).

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount, footprint-compatible with industry-standard 5-pin SOT23 supervisors.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3836K33DBVR and MAX6369KA27+T, the MAX6865UK27D1L+T uniquely combines ultra-low ICC, precise 2.7V VTH, MR input, and watchdog in one 5-pin SOT23-enabling full supervisory coverage without trade-offs in power, accuracy, or feature set.

Availability

MAX6865UK27D1L+T is available at Aetrix Electronics and suitable for portable medical devices, wireless sensor nodes, handheld diagnostics, and low-power wearables requiring stable component supply across extended production lifecycles.

Supply support for MAX6865UK27D1L+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 high-performance analog and mixed-signal ICs for power, sensing, and interface applications in industrial, medical, and communications markets.

The MAX68xx family delivers nanopower supervisory solutions optimized for battery-critical systems-combining voltage monitoring, manual reset, and watchdog in minimal footprint with guaranteed sub-2V operation.

FAQ

What is the exact reset threshold voltage of the MAX6865UK27D1L+T?

The MAX6865UK27D1L+T has a factory-trimmed reset threshold of 2.7V with ±2.5% tolerance over temperature (−40°C to +85°C). This value is fixed and encoded in the "27" suffix per Maxim's Threshold Suffix Guide (Table 2), eliminating need for external resistor calibration. The device guarantees reset assertion when VCC falls below this threshold and deassertion only after VCC exceeds it plus hysteresis (0.5% of VTH).

Does the MAX6865UK27D1L+T require external components for basic operation?

No, the MAX6865UK27D1L+T operates autonomously with zero external components for core functions: its MR input includes a 10kΩ internal pullup to VCC, the watchdog timer needs no timing capacitor, and the push-pull RESET output drives µP reset pins directly. Only a 0.1µF ceramic bypass capacitor on VCC to GND is recommended for noise immunity-no resistors, capacitors, or diodes are required for reset generation or watchdog operation.

How does the watchdog timer in the MAX6865UK27D1L+T clear and expire?

The MAX6865UK27D1L+T watchdog timer clears on any rising or falling edge at the WDI pin and expires only if WDI remains static (high or low) for longer than 209s (typical, L-suffix). It does not count while RESET is asserted. Once expired, it triggers a full reset pulse for the 10ms timeout period. The timer's 150ns minimum detectable pulse width ensures robustness against noise and contact bounce.

Can the MAX6865UK27D1L+T operate reliably below 1.8V?

Yes, the MAX6865UK27D1L+T is fully specified from VCC = 1.2V to 5.5V and guarantees valid RESET assertion down to VCC = +1.1V. At 1.2V, supply current remains ultra-low (190nA typ), RESET output VOL stays ≤0.3V under 50µA load, and MR/WDI logic thresholds scale with VCC (VIH = 0.7×VCC, VIL = 0.3×VCC), enabling robust operation in single-cell alkaline or LiFePO₄ systems.

What is the function of Pin 1 (RESET) on the MAX6865UK27D1L+T?

Pin 1 of the MAX6865UK27D1L+T is the active-low push-pull RESET output. It drives low (≤0.3V) when VCC drops below 2.7V, MR is pulled low, or the watchdog timer expires-and remains low for the full 10ms reset timeout period after the fault condition clears. Unlike open-drain variants, it requires no external pullup and sources/sinks sufficient current (≥200µA high, ≥1.2mA low) to directly drive standard µP reset inputs.