Analog Devices Inc./Maxim Integrated MAX6865UK45D1L+T

Overview

The MAX6865UK45D1L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring active-high push-pull reset output, manual reset input (MR), and watchdog timer with 209s typical timeout. It monitors VCC from 1.2V to 5.5V, asserts reset when voltage drops below 4.500V (factory-trimmed threshold), and guarantees valid reset down to VCC = +1.1V. Used in battery-powered glucose monitors and portable medical devices requiring ultra-low quiescent current.

For engineers reviewing the MAX6865UK45D1L+T datasheet, MAX6865UK45D1L+T pinout, MAX6865UK45D1L+T application, or MAX6865UK45D1L+T equivalent, key selection criteria include its 170nA typical supply current, 4.500V ±2.5% reset threshold, 10ms minimum reset timeout, 209s watchdog period, and compatibility with noisy low-voltage systems where brownout immunity and long battery life are critical.

Technical Context

This device integrates three core functions: precision voltage monitoring with hysteresis (0.5% of VTH), a glitch-immune manual reset input with 10kΩ internal pullup and 250ns MR-to-reset delay, and a watchdog timer that clears on any WDI edge and expires if WDI remains static beyond 209s (typ). The reset assertion is latched and held for the full timeout after VCC recovery or MR release.

It operates across –40°C to +85°C, supports VCC as low as 1.2V, and maintains guaranteed reset validity down to 1.1V. Its BiCMOS process enables ultra-low ICC (170nA typ at 2.5V) while delivering robust noise immunity - immune to VCC transients ≤40µs at 100mV overdrive - making it suitable for compact, single-cell or dual-cell battery systems.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount. Compact footprint (2.9mm × 1.6mm × 1.1mm) optimized for space-constrained portable designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6865UK45D1L+T, the MAX6864UK45D1L+T offers identical supervision accuracy and ultra-low power but requires active-low reset logic, while the TPS3837K33DBVR trades off watchdog capability and nanopower performance for lower unit cost in simpler systems.

Availability

MAX6865UK45D1L+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign recorders, and wireless telemetry devices requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.

Supply support for MAX6865UK45D1L+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 timing applications in industrial, medical, and portable electronics.

The MAX6854–MAX6869 family delivers nanopower supervisory functions for battery-critical systems-engineered specifically for medical wearables, handheld diagnostics, and energy-harvesting endpoints where µA/nA current budgets and long-term reliability are mandatory.

FAQ

What is the exact reset threshold voltage of the MAX6865UK45D1L+T?

The MAX6865UK45D1L+T has a factory-trimmed reset threshold of +4.500V, with guaranteed 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 "45" corresponds to 4.500V nominal. The device asserts reset when VCC falls below this threshold and holds reset for the full 10ms timeout after recovery.

Does the MAX6865UK45D1L+T include a watchdog timer, and what is its timeout?

Yes, the MAX6865UK45D1L+T includes a watchdog timer with a typical timeout of 209s, denoted by the "L" suffix in the part number. The timer clears on any rising or falling edge at the WDI pin and expires only if WDI remains static beyond this period. It is fully functional across the full operating temperature range and does not require external components.

What type of reset output does the MAX6865UK45D1L+T provide?

The MAX6865UK45D1L+T provides an active-high push-pull reset output on Pin 1. When asserted, RESET drives high to VCC; when deasserted, it pulls low to GND. This eliminates the need for external pullup resistors and ensures direct compatibility with microprocessors requiring active-high reset signals.

Can the MAX6865UK45D1L+T operate reliably at very low supply voltages?

Yes-the MAX6865UK45D1L+T guarantees valid reset assertion down to VCC = +1.1V, and operates across a full supply range of 1.2V to 5.5V. Its internal circuitry remains functional and deterministic at these low voltages, making it suitable for end-of-battery-life detection in single-cell systems without additional supervision circuitry.

Is the MAX6865UK45D1L+T pin-compatible with other devices in the MAX68xx family?

The MAX6865UK45D1L+T uses the standard 5-pin SOT23-5 package and shares identical pinout with MAX6864/MAX6866 variants (RESET/MR/WDI/GND/VCC), but differs from MAX6861–MAX6863 (which use CT instead of WDI) and MAX6854–MAX6856 (which lack WDI). Always verify pin function alignment-not just physical layout-before substitution.