Analog Devices Inc./Maxim Integrated MAX6865UK34D2L+T

Overview

The MAX6865UK34D2L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, combining voltage monitoring (3.315V ±2.5% reset threshold), manual reset input (MR), and watchdog timer (209s typical timeout) with ultra-low 170nA typical supply current. It asserts an active-high push-pull RESET output during VCC brownout, MR assertion, or watchdog timeout, and holds reset for 40ms minimum after recovery - ideal for battery-powered glucose monitors and portable medical devices requiring guaranteed reset validity down to VCC = +1.1V.

For engineers reviewing the MAX6865UK34D2L+T datasheet, MAX6865UK34D2L+T pinout, MAX6865UK34D2L+T application, or MAX6865UK34D2L+T equivalent, key selection criteria include its factory-trimmed 3.315V reset threshold, 209s watchdog timeout (L-suffix), 40ms reset timeout (D2), active-high push-pull output, and immunity to sub-40µs VCC transients - all critical for low-power embedded systems where deterministic reset behavior under marginal supply conditions is mandatory.

Technical Context

This device implements a precision bandgap-based voltage monitor with 2.5% threshold tolerance over -40°C to +85°C, coupled with a temperature-stable RC-based watchdog timer that clears on any WDI edge (rising or falling) and expires if WDI remains static beyond 209s (typ). The internal 10kΩ MR pullup enables direct CMOS-level manual reset initiation without external components.

Its push-pull active-high RESET output is referenced to VCC and guarantees VOH ≥ 0.8×VCC at ISOURCE = 500µA (VCC ≥ 2.38V), while VOL ≤ 0.3V at ISINK = 1.2mA (VCC ≥ 2.38V). Reset deassertion occurs only after VCC exceeds the threshold *and* the 40ms timeout elapses - ensuring µP initialization completes before release.

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 MAX6865UK34D2L+T, MAX6864UK34D2S+T trades long watchdog coverage for faster fault detection, while TPS3837K33DBVR sacrifices supervision depth for cost reduction - making MAX6865UK34D2L+T the sole option meeting stringent medical device requirements for both extended watchdog interval and guaranteed low-VCC reset validity.

Availability

MAX6865UK34D2L+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, MP3 players, and cellular handsets requiring stable component supply with guaranteed long-term availability and RoHS-compliant packaging.

Supply support for MAX6865UK34D2L+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, sensing, and connectivity in demanding industrial, medical, and automotive applications.

The MAX6854–MAX6869 family delivers nanopower supervisory functions for battery-critical systems - engineered to eliminate external components while guaranteeing reset integrity across voltage, temperature, and noise stress conditions.

FAQ

What is the exact reset threshold voltage of the MAX6865UK34D2L+T?

The MAX6865UK34D2L+T has a factory-trimmed reset threshold of 3.315V with ±2.5% tolerance over -40°C to +85°C, as defined by the "34" suffix per Maxim's Threshold Suffix Guide (Table 2). This value is laser-trimmed during production and guaranteed in the Electrical Characteristics table - not a nominal or typical value subject to variation.

Does the MAX6865UK34D2L+T require external components for basic operation?

No, the MAX6865UK34D2L+T operates autonomously with zero external components: it features an internal 10kΩ pullup on MR, no timing capacitors for reset or watchdog, and a push-pull active-high RESET output that drives µP reset pins directly. Only a 0.1µF VCC bypass capacitor is recommended for noise immunity - not required for functional operation.

How does the watchdog timer in the MAX6865UK34D2L+T respond to firmware activity?

The MAX6865UK34D2L+T watchdog timer clears on any rising or falling edge at the WDI pin and expires only if WDI remains static (high or low) for longer than 209s (typical, L-suffix). It does not require high-frequency toggling - a single edge every few minutes suffices - making it ideal for low-duty-cycle firmware in medical devices.

What is the minimum VCC level at which the MAX6865UK34D2L+T guarantees valid RESET assertion?

The MAX6865UK34D2L+T guarantees RESET assertion remains valid down to VCC = +1.1V, as explicitly stated in the Absolute Maximum Ratings and Electrical Characteristics tables. Below this voltage, output drive capability degrades, but the device continues asserting RESET until VCC falls further - critical for fail-safe behavior during deep brownout.

Can the MAX6865UK34D2L+T replace the MAX6864UK34D2S+T without design changes?

No - although both share identical pinout, threshold (3.315V), and reset timeout (40ms), the MAX6865UK34D2L+T uses a 209s watchdog (L-suffix) versus the MAX6864UK34D2S+T's 3.3s watchdog (S-suffix). Firmware must be modified to accommodate the longer timeout interval; using them interchangeably risks undetected firmware hangs.