Analog Devices Inc./Maxim Integrated MAX6865UK34D3L+T

Overview

The MAX6865UK34D3L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, combining voltage monitoring, manual reset input (MR), and watchdog timer (WDI) with factory-trimmed 3.400V reset threshold and 150ms minimum reset timeout. It asserts an active-high push-pull RESET output when VCC drops below threshold, MR is asserted, or watchdog expires - ensuring reliable startup/brownout recovery in ultra-low-power systems. Used in glucose monitors and portable medical devices where supply current <200nA and VCC operation down to 1.1V are critical.

For engineers reviewing the MAX6865UK34D3L+T datasheet, MAX6865UK34D3L+T pinout, MAX6865UK34D3L+T application, or MAX6865UK34D3L+T equivalent, key selection criteria include its 3.400V ±2.5% reset threshold, 150ms/225ms/300ms (min/typ/max) reset timeout, 209s typical watchdog period (L-suffix), 170nA typical supply current at 1.8V, and guaranteed RESET validity down to VCC = 1.1V.

Technical Context

This device implements a precision bandgap-based voltage monitor with 0.5% hysteresis, a digital watchdog timer cleared by WDI edges (150ns pulse width min), and a programmable reset timeout generator. The internal 10kΩ MR pullup and glitch rejection (200ns) enable robust manual reset without external components.

It features dual timing paths: one triggered by VCC falling below VTH (with tRD = 40µs), and another initiated by MR assertion or WDI timeout - both enforcing identical tRP = 150ms (min) deassertion delay. RESET output is push-pull active-high, referenced to VCC, with VOH ≥ 0.8×VCC at ISOURCE = 500µA.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5 (lead-free, +T suffix), footprint-compatible with industry-standard supervisory ICs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK34D3L+T, the MAX6865UK34D3L+T provides active-high RESET compatibility out-of-box; versus TPS3838K33DBVR, it delivers 10× lower ICC and integrated watchdog - critical for battery longevity and firmware reliability in medical IoT endpoints.

Availability

MAX6865UK34D3L+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign recorders, handheld diagnostics, and low-power industrial sensors requiring stable component supply across extended product lifecycles.

Supply support for MAX6865UK34D3L+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 MAX6865UK34D3L+T belongs to the MAX68xx nanopower supervisory family, engineered specifically for battery-critical medical and portable electronics where sub-200nA ICC and guaranteed 1.1V operation are mandatory.

FAQ

What is the exact reset threshold voltage of the MAX6865UK34D3L+T?

The MAX6865UK34D3L+T has a factory-trimmed reset threshold of 3.400V, with tolerance of ±2.5% over -40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "34" corresponds to 3.400V nominal. The device guarantees valid reset assertion down to VCC = 1.1V, making it suitable for brownout detection in Li-ion and coin-cell systems.

Does the MAX6865UK34D3L+T support watchdog functionality, and what is its timeout period?

Yes, the MAX6865UK34D3L+T includes a watchdog timer with L-suffix configuration, providing a typical timeout period of 209 seconds (min 95s, max 487s). The watchdog is edge-triggered - cleared on any rising or falling transition at the WDI pin - and expires only if WDI remains static beyond the timeout window. This behavior is explicitly defined in Table 3 (Watchdog Timeout) and functional diagrams of the MAX6865UK34D3L+T datasheet.

What type of RESET output does the MAX6865UK34D3L+T provide, and how is it interfaced?

The MAX6865UK34D3L+T provides an active-high push-pull RESET output (Pin 1), eliminating the need for an external pullup resistor. It sources current up to 500µA while maintaining VOH ≥ 0.8×VCC, directly compatible with standard µP reset inputs requiring active-high assertion. This configuration is confirmed in the MAX6865-specific pin description (page 8) and Selector Guide (page 16) of the MAX6865UK34D3L+T documentation.

What is the minimum reset timeout period for the MAX6865UK34D3L+T, and how is it set?

The MAX6865UK34D3L+T has a fixed minimum reset timeout period of 150ms, corresponding to the D3 suffix in its part number. This value is specified in Table 4 (Reset Timeout Periods) as D3 = 150ms (min), 225ms (typ), 300ms (max). Unlike MAX6861–MAX6863 variants, the MAX6865UK34D3L+T does not feature a CT pin for dynamic timeout selection - the D3 timeout is permanently configured at wafer trim.

Is the MAX6865UK34D3L+T compatible with 1.8V supply systems, and what is its supply current at that voltage?

Yes, the MAX6865UK34D3L+T operates across 1.2V to 5.5V, fully supporting 1.8V systems. At VCC = 1.8V and TA = +25°C, its typical supply current is 170nA (with max 370nA), as specified in the Electrical Characteristics table (page 2). This ultralow ICC enables multi-year operation from small batteries - a key design target validated in typical operating curves (Figure toc02).