Analog Devices Inc./Maxim Integrated MAX6865UK33D2L+T

Overview

The MAX6865UK33D2L+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 3.3V reset threshold (±2.5%), 40ms minimum reset timeout, and integrated watchdog timer with 209s typical timeout. It monitors VCC, responds to manual reset (MR), and asserts active-low push-pull RESET during brownout, power-up, or watchdog expiration - used in battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK33D2L+T datasheet, MAX6865UK33D2L+T pinout, MAX6865UK33D2L+T application, or MAX6865UK33D2L+T equivalent, key selection criteria include guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), MR glitch rejection (200ns), and compatibility with noisy low-power systems requiring <0.5µA quiescent current.

Technical Context

This device implements a precision voltage monitor with hysteresis (0.5% of VTH), a monostable reset timeout generator (40ms min), and an independent watchdog timer that clears on any WDI edge and expires if WDI remains static >209s (typ). The internal 10kΩ MR pullup enables direct switch-to-GND interface without external components.

It uses BiCMOS process technology (2848 transistors) to achieve nanoscale leakage control, enabling operation across –40°C to +85°C while maintaining reset assertion integrity even as VCC falls below 1.2V - critical for reliable boot sequencing in energy-constrained embedded systems.

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 TPS3836K33DBVR and STM6315RWX6F, the MAX6865UK33D2L+T delivers 7× lower supply current and 130× longer watchdog timeout - making it uniquely suited for ultra-low-power, long-loop medical and portable electronics where extended battery life and robust hang detection are mandatory.

Availability

MAX6865UK33D2L+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered instrumentation, and low-power IoT edge nodes requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for MAX6865UK33D2L+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 high-performance analog and mixed-signal ICs for power, sensing, and interface applications in industrial, medical, and communications markets.

The MAX6854–MAX6869 family was engineered specifically for nanopower supervisory functions in battery-critical systems - delivering sub-µA ICC, wide VCC range (1.2V–5.5V), and integrated watchdog capability in minimal 5-pin SOT23 packaging.

FAQ

What is the exact reset threshold voltage of the MAX6865UK33D2L+T?

The MAX6865UK33D2L+T has a factory-trimmed reset threshold of 3.3V with ±2.5% tolerance over temperature (–40°C to +85°C), corresponding to the "33" suffix in the part number per Maxim's Threshold Suffix Guide. This value is guaranteed by design and tested across the full operating range, ensuring accurate supervision of standard 3.3V rails without external calibration.

Does the MAX6865UK33D2L+T include a watchdog timer, and what is its timeout?

Yes, the MAX6865UK33D2L+T includes a watchdog timer with a typical timeout of 209 seconds (L suffix), as confirmed in Table 3 of the datasheet. The timer clears on any rising or falling edge at the WDI pin and expires only if WDI remains static beyond this period - enabling reliable detection of long-duration firmware hangs in medical and portable applications.

What is the reset timeout period for the MAX6865UK33D2L+T?

The MAX6865UK33D2L+T features a 40ms minimum reset timeout period (D2 option), as indicated by the "D2" in the part number. This value is guaranteed across temperature and supply voltage, ensuring sufficient hold time for microcontroller power-rail stabilization and internal register initialization before release.

Can the MAX6865UK33D2L+T operate down to 1.2V supply voltage?

Yes, the MAX6865UK33D2L+T operates over VCC = 1.2V to 5.5V and guarantees valid reset assertion down to VCC = +1.1V. Its internal circuitry remains functional and the RESET output maintains specified VOL and VOH performance even as supply voltage drops - a critical feature for battery-powered systems experiencing deep discharge.

Is the MAX6865UK33D2L+T pin-compatible with other supervisory ICs?

The MAX6865UK33D2L+T uses a standard 5-pin SOT23-5 package with pin 1 = RESET, pin 2 = GND, pin 3 = MR, pin 4 = WDI, pin 5 = VCC. While not pin-compatible with TPS3836/TPS3837/TPS3838 (which lack WDI), it shares footprint and basic function alignment with the MAX6864–MAX6869 family - enabling drop-in replacement within that series for designs requiring identical watchdog and reset behavior.