Analog Devices Inc./Maxim Integrated MAX6865UK24D5L+T

Overview

The MAX6865UK24D5L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, combining voltage monitoring (2.4V 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 signal during VCC brownout, MR assertion, or watchdog timeout, and holds reset for 300ms minimum after recovery - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK24D5L+T datasheet, MAX6865UK24D5L+T pinout, MAX6865UK24D5L+T application, or MAX6865UK24D5L+T equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), fixed 300ms reset timeout, and compatibility with noisy low-power systems requiring reliable power-on reset and software fault detection.

Technical Context

This device implements a dual-trigger reset architecture: one path monitors VCC against a factory-trimmed 2.400V threshold (±2.5%), while a second path detects watchdog timeout on the WDI input. The internal watchdog timer clears on any WDI edge and expires if WDI remains static beyond 209s (typ), with temperature-stable performance across –40°C to +85°C.

The MAX6865UK24D5L+T uses BiCMOS process technology (2848 transistors) to achieve 170nA typical ICC at 2.5V, supports CMOS-level MR and WDI inputs (VIH = 0.7×VCC, VIL = 0.3×VCC), and features an internally pulled-up MR pin (10kΩ) with 1µs minimum pulse width and 250ns MR-to-reset delay.

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 MAX6864UK24D3S+T and TPS3836K24DBVR, the MAX6865UK24D5L+T uniquely delivers 170nA ICC, 300ms reset timeout, and 209s watchdog in a single 5-pin SOT23 - enabling robust, long-life supervision where power budget and software reliability are co-constrained.

Availability

MAX6865UK24D5L+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered instrumentation, and low-power IoT nodes requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for MAX6865UK24D5L+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 MAX6865UK24D5L+T belongs to the MAX68xx nanopower supervisory family, engineered specifically for ultra-low-power battery-operated systems requiring simultaneous voltage monitoring, manual reset, and long-interval watchdog supervision.

FAQ

What is the exact reset threshold voltage of the MAX6865UK24D5L+T?

The MAX6865UK24D5L+T has a factory-trimmed reset threshold of 2.400V with ±2.5% tolerance over –40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) where suffix "24" corresponds to 2.400V nominal, and in Electrical Characteristics where VTH is specified as VTH ±2.5%. The MAX6865UK24D5L+T maintains this accuracy without external calibration.

Does the MAX6865UK24D5L+T require an external pullup resistor on the RESET pin?

No, the MAX6865UK24D5L+T features an active-high push-pull RESET output, which actively drives high during reset assertion and low during deassertion. Unlike open-drain variants, it does not require an external pullup resistor - simplifying PCB layout and reducing BOM count. This is explicitly stated in the MAX6865 pin description and functional diagram.

What is the watchdog timeout period for the MAX6865UK24D5L+T, and how is it selected?

The MAX6865UK24D5L+T uses the "L" suffix, specifying a typical watchdog timeout of 209s (min 95s, max 487s). This value is fixed per ordering code and cannot be adjusted externally. The watchdog timer clears on any rising or falling edge at the WDI pin and expires only if WDI remains static beyond the timeout period - a behavior confirmed in the Watchdog Timer section and Table 3.

Can the MAX6865UK24D5L+T operate reliably at VCC = 1.3V?

Yes, the MAX6865UK24D5L+T guarantees valid RESET assertion down to VCC = +1.1V, as stated in the Features list and Electrical Characteristics table. At 1.3V, all core functions - including voltage monitoring, MR response, and watchdog timing - remain fully operational and specified. This enables use with deeply discharged lithium or alkaline cells where other supervisors fail.

How does the manual reset (MR) function interact with the watchdog and power-on reset in the MAX6865UK24D5L+T?

In the MAX6865UK24D5L+T, MR assertion forces immediate RESET activation regardless of VCC level or watchdog state. RESET remains asserted for the full 300ms timeout after MR is released, overriding concurrent watchdog or brownout conditions. The internal 10kΩ MR pullup ensures default high state, and MR accepts standard CMOS logic levels - all verified in the Detailed Description and Pin Function tables.