Analog Devices Inc./Maxim Integrated MAX6865UK20D1L+T

Overview

The MAX6865UK20D1L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, combining voltage monitoring (2.000V reset threshold), manual reset input (MR), and watchdog timer (209s typical timeout) with ultra-low 170nA supply current. It asserts an active-high push-pull RESET output during VCC brownout, MR assertion, or watchdog timeout, ensuring reliable µP initialization in battery-critical systems.

For engineers reviewing the MAX6865UK20D1L+T datasheet, MAX6865UK20D1L+T pinout, MAX6865UK20D1L+T application, or MAX6865UK20D1L+T equivalent, key selection criteria include its 2.000V factory-trimmed threshold, 10ms minimum reset timeout, 209s watchdog period, guaranteed RESET validity down to VCC = +1.1V, and compatibility with portable medical and handheld electronics requiring sub-µA quiescent current.

Technical Context

This device implements a precision bandgap-based voltage monitor with ±2.5% 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). The internal reset timeout generator uses RC-based timing with six selectable periods, and the MR input features 10kΩ internal pullup and 250ns MR-to-reset delay.

The MAX6865UK20D1L+T delivers active-high push-pull RESET referenced to VCC, supporting VOH ≥ 0.8×VCC at ISOURCE = 500µA and VOL ≤ 0.3V at ISINK = 1.2mA. Its immunity to short VCC transients (<40µs for 100mV overdrive) and operation down to VCC = +1.1V enable robust use in low-voltage, noise-prone embedded systems.

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 MAX6864UK20D1L+T, the MAX6865UK20D1L+T's active-high RESET simplifies interface to most modern ARM Cortex-M MCUs; versus TPS3836K20DBVR, its 170nA ICC enables >5× longer battery runtime in energy-harvested or coin-cell systems, at the cost of requiring Maxim-specific watchdog software integration.

Availability

MAX6865UK20D1L+T is available at Aetrix Electronics and suitable for portable medical devices, wearable health monitors, industrial handheld terminals, and low-power IoT sensors requiring stable component supply with guaranteed long-term availability.

Supply support for MAX6865UK20D1L+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 MAX6865UK20D1L+T belongs to Maxim's nanopower µP supervisory family, engineered specifically for ultra-low-power portable electronics where battery longevity, brownout resilience, and watchdog reliability are critical.

FAQ

What is the exact reset threshold voltage of the MAX6865UK20D1L+T?

The MAX6865UK20D1L+T has a factory-trimmed reset threshold of 2.000V with ±2.5% tolerance over -40°C to +85°C, as defined by the "20" suffix in its part number per Maxim's Threshold Suffix Guide (Table 2). This value is measured at VCC falling and guarantees reliable detection of brownout on 2.0V rails.

Does the MAX6865UK20D1L+T require external components for basic operation?

No, the MAX6865UK20D1L+T operates autonomously with no external components required: it includes an internal 10kΩ MR pullup resistor, factory-calibrated timing network, and push-pull RESET driver. Only a 0.1µF VCC bypass capacitor to GND is recommended for noise immunity, per the Typical Operating Circuit.

How does the watchdog timer in the MAX6865UK20D1L+T function?

The MAX6865UK20D1L+T watchdog timer expires after 209s (typical, L-suffix) if the WDI input remains static (high or low); it resets on any rising or falling edge. The timer is disabled during RESET assertion and resumes counting immediately upon RESET deassertion, enabling precise firmware health monitoring without hardware modifications.

What is the minimum VCC voltage at which the MAX6865UK20D1L+T guarantees valid RESET output?

The MAX6865UK20D1L+T guarantees RESET output validity down to VCC = +1.1V, meaning the active-high RESET signal remains logically correct and capable of driving a µP input even during deep brownout conditions - a critical feature for fail-safe operation in battery-powered systems.

Is the MAX6865UK20D1L+T pin-compatible with other devices in the MAX68xx family?

The MAX6865UK20D1L+T shares the same 5-pin SOT23-5 package and pinout (RESET, GND, MR, WDI, VCC) with MAX6864/MAX6866/MAX6867–MAX6869 variants, but differs from MAX6861–MAX6863 (which use CT instead of WDI) and MAX6854–MAX6860 (which lack WDI). Pin compatibility is limited to the MAX6864–MAX6869 subgroup.