Analog Devices Inc./Maxim Integrated MAX6865UK43D3L+T

Overview

The MAX6865UK43D3L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, combining voltage monitoring (4.300V 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, and guarantees valid reset operation down to VCC = +1.1V - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK43D3L+T datasheet, MAX6865UK43D3L+T pinout, MAX6865UK43D3L+T application, or MAX6865UK43D3L+T equivalent, this page delivers verified functional identity, exact reset threshold and watchdog timing, confirmed SOT23-5 pin mapping, and two validated alternative parts with documented technical and application differences.

Technical Context

The MAX6865UK43D3L+T implements a dual-trigger reset architecture: one path responds to VCC falling below 4.300V ±2.5%, another to MR low assertion, and a third to WDI inactivity exceeding 209s (L-suffix). Its internal watchdog timer clears on any WDI edge, MR assertion, or RESET assertion - ensuring robust recovery from software hangs without false triggers.

Reset deassertion follows a fixed 150ms minimum timeout (D3 suffix) after VCC rises above threshold and MR deasserts; the active-high push-pull RESET output sources ≥500µA at VCC ≥2.38V while maintaining VOH ≥0.8×VCC, enabling direct interface with 1.8V–5.5V µP reset inputs without external level-shifting.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5 (lead-free, +T suffix), 2.9mm × 1.6mm footprint, 1.1mm height - compatible with high-density portable PCB layouts and reflow assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK43D3S+T and TPS3836K33DBVR, the MAX6865UK43D3L+T uniquely delivers 209s watchdog supervision, 4.300V precision threshold, and nanopower 170nA operation - making it the only option for long-duration, battery-constrained medical and industrial IoT endpoints requiring both brownout and software-failure protection.

Availability

MAX6865UK43D3L+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign recorders, industrial handheld scanners, and smart wearable sensors requiring stable component supply across extended product lifecycles.

Supply support for MAX6865UK43D3L+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 MAX6854–MAX6869 family targets ultra-low-power microprocessor supervision in battery-operated medical and portable electronics, emphasizing nanopower consumption, guaranteed reset validity at low VCC, and integrated watchdog functionality.

FAQ

What is the exact reset threshold voltage of the MAX6865UK43D3L+T?

The MAX6865UK43D3L+T has a factory-trimmed reset threshold of 4.300V 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 "43" corresponds to 4.300V nominal. The device guarantees valid reset assertion down to VCC = +1.1V, supporting reliable operation during deep brownout conditions.

Does the MAX6865UK43D3L+T include a watchdog timer, and what is its timeout period?

Yes, the MAX6865UK43D3L+T includes a watchdog timer with a typical timeout period of 209s, indicated by the "L" suffix in the part number. This is verified in Table 3 (Watchdog Timeout) of the datasheet, which specifies L-suffix devices as having 95s (min), 209s (typ), and 487s (max) timeout. The timer clears on any rising or falling edge at the WDI pin, preventing false timeouts during normal firmware operation.

What is the reset timeout period of the MAX6865UK43D3L+T, and how is it configured?

The MAX6865UK43D3L+T has a fixed minimum reset timeout period of 150ms, denoted by the "D3" suffix. As confirmed in Table 4 (Reset Timeout Periods), D3 corresponds to 150ms (min), 225ms (typ), and 300ms (max). This timeout is factory-set and non-adjustable - unlike MAX6861–MAX6863 variants, the MAX6865UK43D3L+T does not feature a CT pin for dynamic timeout selection.

What type of RESET output does the MAX6865UK43D3L+T provide, and how is it connected?

The MAX6865UK43D3L+T provides an active-high push-pull RESET output (Pin 1), as specified in the MAX6865 pin description on page 8 of the datasheet. This output sources current when deasserted (VOH ≥0.8×VCC at ISOURCE = 500µA) and sinks current when asserted (VOL ≤0.3V at ISINK = 1.2mA), eliminating the need for an external pullup resistor and enabling direct connection to µP reset inputs rated for 1.8V–5.5V logic levels.

Is the MAX6865UK43D3L+T compatible with standard SOT23-5 footprints and reflow processes?

Yes, the MAX6865UK43D3L+T uses a standard 5-pin SOT23-5 package (2.9mm × 1.6mm, 1.1mm height) with lead-free termination (+T suffix), fully compatible with IPC-7351B SOT-23-5 land patterns and JEDEC J-STD-020 reflow profiles. The device is rated for lead-free soldering at 300°C for 10 seconds, and its thermal characteristics support standard convection and vapor-phase reflow processes without derating.