Analog Devices Inc./Maxim Integrated MAX6865UK35D5L+T

Overview

MAX6865UK35D5L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 3.5V reset threshold (±2.5%), 600ms minimum reset timeout (D5), and integrated watchdog timer with 209s typical timeout (L suffix). It monitors VCC, responds to manual reset (MR), and asserts active-high push-pull RESET during brownout or watchdog expiration - used in battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK35D5L+T datasheet, MAX6865UK35D5L+T pinout, MAX6865UK35D5L+T application, or MAX6865UK35D5L+T equivalent, key selection criteria include guaranteed RESET validity down to VCC = +1.1V, immunity to sub-40µs VCC transients, MR glitch rejection of 200ns, and compatibility with 1.2V–5.5V supply rails in space-constrained portable systems.

Technical Context

The MAX6865UK35D5L+T implements a precision bandgap-based voltage monitor with 0.5%VTH hysteresis and a digital watchdog timer that clears on any WDI edge (rising or falling) and expires if WDI remains static beyond 209s (typ). Its internal 10kΩ MR pullup enables direct switch-to-GND manual reset without external components.

RESET assertion is triggered by VCC falling below 3.5V, MR low, or watchdog timeout - and remains asserted for ≥600ms after VCC rises above threshold and MR deasserts. The active-high push-pull output drives directly to VCC with VOH ≥0.8×VCC at 500µA source current, eliminating need for external pullups.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount, footprint compatible with industry-standard 5-pin SOT23 layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3836K33DBVR and MAX6369KA29+T, the MAX6865UK35D5L+T uniquely combines 3.5V precision threshold, 600ms configurable timeout, MR input, and 209s watchdog - enabling robust fail-safe operation in battery-powered medical and industrial edge devices where both power integrity and software execution integrity must be enforced.

Availability

MAX6865UK35D5L+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign loggers, and industrial handheld scanners requiring stable component supply, long-term lifecycle support, and lead-free compliance.

Supply support for MAX6865UK35D5L+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 communications systems.

The MAX6865UK35D5L+T belongs to the MAX68xx nanopower supervisory family, engineered specifically for ultra-low-power, high-reliability reset and watchdog functions in battery-operated portable electronics.

FAQ

What is the exact reset threshold voltage of MAX6865UK35D5L+T?

The MAX6865UK35D5L+T has a factory-trimmed reset threshold of 3.500V 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 "35" corresponds to 3.5V nominal. The device guarantees valid RESET assertion down to VCC = +1.1V, making it suitable for deep brownout detection in low-voltage systems.

Does MAX6865UK35D5L+T support active-high or active-low reset output?

The MAX6865UK35D5L+T features an active-high push-pull RESET output, as confirmed by its pin description (Pin 1 = RESET, active-high) and Selector Guide entry. It drives high during fault conditions and deasserts low after timeout - eliminating need for external pullup resistors and enabling direct connection to MCUs with active-high reset inputs.

What is the watchdog timeout behavior of MAX6865UK35D5L+T?

The MAX6865UK35D5L+T implements a watchdog timer with 209s typical timeout (L suffix), as specified in Table 3. The timer clears on any rising or falling edge at WDI and expires only if WDI remains static beyond this period. During RESET assertion, the watchdog is disabled; it resumes counting immediately upon RESET deassertion.

Can MAX6865UK35D5L+T operate with supply voltages below 1.8V?

Yes - the MAX6865UK35D5L+T operates across 1.2V to 5.5V, with 170nA typical supply current measured at VCC = 1.8V. Its RESET output remains valid down to VCC = +1.1V, and all electrical characteristics (including MR input thresholds and WDI edge detection) are guaranteed over the full 1.2V–5.5V range per Absolute Maximum Ratings and Electrical Characteristics tables.

Is MAX6865UK35D5L+T pin-compatible with other MAX68xx variants?

The MAX6865UK35D5L+T uses the standard 5-pin SOT23-5 package and shares identical pinout with MAX6864–MAX6866 (RESET/MR/WDI/GND/VCC), but differs from MAX6861–MAX6863 (which use CT instead of WDI) and MAX6854–MAX6856 (which lack WDI). Pin compatibility is limited to the MAX6864/MAX6865/MAX6866 subgroup - not across the entire MAX68xx family.