Analog Devices Inc./Maxim Integrated MAX6865UK43D6S+T

Overview

The MAX6865UK43D6S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, a factory-trimmed 4.300V reset threshold (±2.5%), and a 1200ms minimum reset timeout period. It integrates manual reset input (MR), watchdog timer with 209s typical timeout, and push-pull active-high RESET output - designed for reliable power-up/brownout monitoring in battery-critical portable medical and consumer devices.

For engineers reviewing the MAX6865UK43D6S+T datasheet, MAX6865UK43D6S+T pinout, MAX6865UK43D6S+T application, or MAX6865UK43D6S+T equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), watchdog edge-triggered clearing logic, and lead-free SOT23-5 packaging compliant with RoHS requirements.

Technical Context

The MAX6865UK43D6S+T implements a dual-monitoring architecture: a precision voltage detector with hysteresis (0.5% of VTH) triggers reset on VCC falling below 4.300V, while a monolithic watchdog timer monitors WDI transitions and expires after 209s (typ) if no edge occurs. Reset assertion persists for 1200ms after VCC recovery and MR deassertion, ensuring µP initialization completes before release.

Its push-pull active-high RESET output delivers VOH ≥ 0.8×VCC (at ISOURCE = 500µA) and VOL ≤ 0.3V (at ISINK = 1.2mA), supporting direct interface to 1.71V–5.5V logic domains. The MR input features 10kΩ internal pullup, 1µs minimum pulse width, and 200ns glitch rejection - enabling robust momentary switch or CMOS-level reset initiation without external components.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, RoHS-compliant, 2.9mm × 1.6mm footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK43D6S+T, the MAX6865UK43D6S+T adds essential watchdog functionality for safety-critical firmware monitoring, while retaining identical reset accuracy and low-power performance; versus TPS3837K33DBVR, it delivers 20× lower supply current and higher reset threshold flexibility but requires WDI signal routing.

Availability

MAX6865UK43D6S+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered industrial scanners, and wearable health sensors requiring stable component supply with guaranteed long-term availability and RoHS-compliant packaging.

Supply support for MAX6865UK43D6S+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 and mixed-signal ICs for power management, sensing, and interface applications in industrial, medical, and communications markets.

The MAX6865UK43D6S+T belongs to Maxim's nanopower µP supervisory family, engineered specifically for ultra-low-power, high-reliability reset and watchdog functions in space-constrained, battery-dependent systems.

FAQ

What is the exact reset threshold voltage of the MAX6865UK43D6S+T?

The MAX6865UK43D6S+T has a factory-trimmed reset threshold voltage of 4.300V with ±2.5% tolerance over -40°C to +85°C, as defined by the "43" suffix in its part number per Maxim's Threshold Suffix Guide (Table 2). This value is guaranteed by design and tested during production, ensuring accurate supervision of 3.3V or 5V rails without external calibration.

Does the MAX6865UK43D6S+T require external components for basic operation?

No, the MAX6865UK43D6S+T operates autonomously with zero external components for core functionality: its MR input includes a 10kΩ internal pullup, the RESET output is push-pull active-high (no pullup needed), and the watchdog timer clears on WDI edges without external timing elements. Only a 0.1µF ceramic capacitor from VCC to GND is recommended for noise suppression - a standard practice, not a requirement.

How does the watchdog timer in the MAX6865UK43D6S+T clear and expire?

The MAX6865UK43D6S+T watchdog timer clears on any rising or falling edge at the WDI pin and expires after 209s (typical, L-suffix) if no edge occurs. It does not monitor level duration alone - this edge-triggered behavior prevents infinite loops from masking firmware faults. The timer remains halted while RESET is asserted and resumes counting immediately upon reset deassertion.

What is the minimum VCC voltage at which the MAX6865UK43D6S+T guarantees valid reset output?

The MAX6865UK43D6S+T guarantees valid RESET output down to VCC = +1.1V, meaning the active-high RESET signal remains logically correct (high during reset, low otherwise) even as the supply drops into deep brownout. This specification ensures deterministic behavior across the full discharge curve of lithium-based batteries, critical for portable medical devices.

Is the MAX6865UK43D6S+T pin-compatible with other devices in the MAX68xx family?

The MAX6865UK43D6S+T uses the standard 5-pin SOT23-5 package and shares identical pinout (RESET, GND, MR, WDI, VCC) with MAX6864/MAX6866/MAX6867–MAX6869 variants. However, it is not pin-compatible with MAX6854–MAX6863 series, which substitute CT or I.C. pins for WDI - physical placement requires verification against the specific variant's Pin Configuration diagram.