Analog Devices Inc./Maxim Integrated MAX6865UK22D1L+T

Overview

MAX6865UK22D1L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 2.235V reset threshold (suffix '22'), 10ms minimum reset timeout (D1), and 209s typical watchdog timeout (L). It monitors VCC, responds to manual reset (MR) assertion, and triggers reset on watchdog timer expiration - designed for battery-critical portable medical and handheld devices.

For engineers reviewing the MAX6865UK22D1L+T datasheet, MAX6865UK22D1L+T pinout, MAX6865UK22D1L+T application, or MAX6865UK22D1L+T equivalent, key selection factors include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), push-pull active-high RESET output, and integrated MR pullup (10kΩ).

Technical Context

The MAX6865UK22D1L+T implements a dual-trigger reset architecture: it asserts RESET when VCC falls below 2.235V, when MR is pulled low, or when WDI remains static beyond 209s (typ). Its internal watchdog timer clears on any WDI edge, MR assertion, or RESET assertion - preventing false timeouts during software recovery sequences.

This variant belongs to the MAX6864–MAX6869 series with active-high push-pull RESET output, no CT pin, and fixed D1 (10ms min) reset timeout. Unlike MAX6861–MAX6863, it lacks pin-selectable timeout; unlike MAX6854–MAX6856, it includes both MR and WDI inputs and supports watchdog supervision.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, -40°C to +85°C operating range.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6865UK22D1L+T, the S-suffix variant offers faster watchdog response at the cost of reduced hang-detection window, while the TPS3837K22DBVR trades watchdog capability and nanopower operation for TI's production support and simpler qualification path - neither is pin- or functionally identical.

Availability

MAX6865UK22D1L+T is available at Aetrix Electronics and suitable for portable medical devices, industrial handheld scanners, wireless sensor nodes, and battery-powered patient monitors requiring stable component supply across extended product lifecycles.

Supply support for MAX6865UK22D1L+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 MAX6864–MAX6869 family delivers nanopower supervisory functions with integrated watchdog timers for battery-constrained embedded systems where reliability and multi-year operation are critical.

FAQ

What is the exact reset threshold voltage of MAX6865UK22D1L+T?

The MAX6865UK22D1L+T has a factory-trimmed reset threshold voltage of 2.235V, with ±2.5% tolerance over temperature (-40°C to +85°C). This value is defined by the '22' suffix in the part number and is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet. The device asserts RESET when VCC falls below this threshold and holds it for the 10ms minimum timeout period after VCC rises above it.

Does MAX6865UK22D1L+T support active-high or active-low reset output?

MAX6865UK22D1L+T features an active-high push-pull RESET output. When a fault occurs (VCC drop, MR assertion, or watchdog timeout), RESET transitions from low to high and remains high for the 10ms reset timeout period. This matches µP reset inputs requiring active-high assertion and eliminates the need for external pullup resistors - a key distinction from open-drain or active-low variants in the same family.

What is the watchdog timeout period for MAX6865UK22D1L+T, and how is it triggered?

MAX6865UK22D1L+T provides a 209s typical watchdog timeout period (L suffix), with min/max values of 95s and 487s. It is triggered when the WDI input remains static (high or low) longer than this period. The internal timer resets on every WDI edge, MR assertion, or RESET assertion - ensuring reliable detection of firmware hangs while ignoring transient noise or intentional pauses.

Can MAX6865UK22D1L+T operate reliably at very low supply voltages?

Yes, MAX6865UK22D1L+T guarantees valid RESET assertion down to VCC = +1.1V, as specified in the Electrical Characteristics table. Its 170nA typical supply current at 1.8V and operational range from 1.2V to 5.5V make it suitable for deep brownout scenarios in coin-cell and alkaline-powered systems. Below 1.1V, RESET behavior is not guaranteed - consistent with most nanopower supervisors.

Is MAX6865UK22D1L+T pin-compatible with other devices in the MAX68xx family?

MAX6865UK22D1L+T uses the standard 5-pin SOT23-5 package and shares identical pinout with MAX6864, MAX6866, MAX6867, MAX6868, and MAX6869 - pins 1 (RESET), 2 (GND), 3 (MR), 4 (WDI), and 5 (VCC). However, it is not pin-compatible with MAX6861–MAX6863 (which use CT instead of WDI) or MAX6854–MAX6856 (which lack WDI). Always verify functional compatibility beyond pin count.