Analog Devices Inc./Maxim Integrated MAX6865UK46D2L+T

Overview

The MAX6865UK46D2L+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 4.625V reset threshold (±2.5%), and dual watchdog timeout options (3.3s or 209s typ). It integrates voltage monitoring, manual reset input (MR), and watchdog timer (WDI) functions to ensure reliable system startup and fault recovery in battery-powered medical and portable electronics.

For engineers reviewing the MAX6865UK46D2L+T datasheet, MAX6865UK46D2L+T pinout, MAX6865UK46D2L+T application, or MAX6865UK46D2L+T equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), push-pull active-high RESET output, and compatibility with noisy low-power systems requiring deterministic reset timing and watchdog supervision.

Technical Context

The MAX6865UK46D2L+T implements a precision bandgap-based voltage monitor with 2.5% threshold tolerance and hysteresis of 0.5% VTH, enabling stable brownout detection across -40°C to +85°C. Its watchdog timer clears on any WDI edge (rising or falling) and triggers reset if WDI remains static beyond the selected timeout (S = 3.3s typ or L = 209s typ).

Reset assertion occurs when VCC falls below 4.625V, MR is pulled low, or WDI times out; the RESET output remains asserted for a fixed 40ms minimum timeout (D2 option) after all conditions clear. The device uses internal 10kΩ MR pullup and requires no external components beyond standard 0.1µF VCC bypassing.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK46D2L+T and TPS3838K33DBVR, the MAX6865UK46D2L+T uniquely delivers active-high RESET, ultra-low 170nA ICC, and 209s watchdog in one 5-pin SOT23 package - making it optimal for space-constrained, battery-powered medical devices requiring both precise voltage supervision and long-interval firmware health monitoring.

Availability

MAX6865UK46D2L+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, MP3 players, and cell phones requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.

Supply support for MAX6865UK46D2L+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 consumer markets.

The MAX6854–MAX6869 family was engineered specifically for ultra-low-power microprocessor supervision in battery-operated medical and portable electronics, emphasizing nanoscale current consumption, robust transient immunity, and integrated watchdog functionality.

FAQ

What is the exact reset threshold voltage of the MAX6865UK46D2L+T?

The MAX6865UK46D2L+T has a factory-trimmed reset threshold voltage of +4.625V, with guaranteed tolerance of ±2.5% over the full -40°C to +85°C temperature range. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "46" corresponds to 4.625V nominal. The device asserts reset when VCC falls below this threshold and holds reset for the D2 timeout period (40ms min) after VCC recovers.

Does the MAX6865UK46D2L+T support active-high or active-low reset output?

The MAX6865UK46D2L+T provides an active-high push-pull RESET output, as confirmed by its pin description (Pin 1 = RESET, active-high) and Selector Guide entry. Unlike the MAX6864 variant (active-low), the MAX6865 drives high during reset assertion and returns low when deasserted - directly compatible with µPs requiring active-high reset signaling without external inverters or pullups.

What is the watchdog timeout period for the MAX6865UK46D2L+T?

The MAX6865UK46D2L+T features a 209s typical watchdog timeout period, indicated by the "L" suffix in its part number. Per Table 3 (Watchdog Timeout), the L option specifies min/typ/max values of 95s/209s/487s. The timer resets on any WDI edge and triggers reset if WDI remains static beyond this interval - ideal for long-duration firmware loops in medical devices.

Can the MAX6865UK46D2L+T operate reliably at VCC = 1.1V?

Yes, the MAX6865UK46D2L+T guarantees valid reset assertion down to VCC = +1.1V, as explicitly stated in the Electrical Characteristics table under "Guaranteed Reset Valid to VCC = +1.1V". This ensures deterministic behavior during deep brownout conditions where other supervisors may fail, critical for maintaining safety integrity in battery-powered patient monitors.

Is an external pullup resistor required for the RESET output of the MAX6865UK46D2L+T?

No, an external pullup resistor is not required for the MAX6865UK46D2L+T because it features a push-pull active-high RESET output. The internal driver actively sources current to pull RESET high during assertion and sinks current to pull it low when deasserted - eliminating dependency on external components and simplifying PCB layout compared to open-drain alternatives.