Analog Devices Inc./Maxim Integrated MAX6865UK42D1L+T

Overview

The MAX6865UK42D1L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 4.200V reset threshold (±2.5%), 10ms 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 expiry - used in battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK42D1L+T datasheet, MAX6865UK42D1L+T pinout, MAX6865UK42D1L+T application, or MAX6865UK42D1L+T equivalent, this page delivers verified functional identity, exact pin roles, confirmed timing parameters, real-world use cases, and validated alternative options for low-power embedded system design.

Technical Context

This device implements a precision voltage monitor with hysteresis (0.5% of VTH), a glitch-immune manual reset input (250ns MR-to-reset delay, 1µs minimum pulse width), and a watchdog timer that clears on any WDI edge and expires if WDI remains static beyond 209s (typ). The internal 10kΩ MR pullup eliminates external components.

RESET assertion is guaranteed valid down to VCC = +1.1V, and the circuit remains immune to VCC transients ≤40µs at 100mV overdrive. No external capacitor or resistor is required for basic operation - only a 0.1µF VCC bypass is recommended.

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 MAX6865UK42D1L+T uniquely combines 4.2V precision threshold, 209s watchdog, and 170nA ICC in one SOT23-5 package - enabling robust, long-life supervision where both voltage margin and firmware execution integrity are critical.

Availability

MAX6865UK42D1L+T is available at Aetrix Electronics and suitable for portable medical devices, wearable health monitors, and low-power IoT edge sensors requiring stable component supply across extended production lifecycles.

Supply support for MAX6865UK42D1L+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 MAX68xx family delivers nanopower supervisory circuits optimized for battery-critical applications - combining voltage monitoring, manual reset, and watchdog functions in minimal footprint without compromising accuracy or reliability.

FAQ

What is the exact reset threshold voltage of the MAX6865UK42D1L+T?

The MAX6865UK42D1L+T has a factory-trimmed reset threshold of 4.200V 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 "42" corresponds to 4.200V nominal. The MAX6865UK42D1L+T maintains this specification without external calibration.

Does the MAX6865UK42D1L+T include a watchdog timer, and what is its timeout?

Yes, the MAX6865UK42D1L+T includes a watchdog timer with 209s typical timeout (L-suffix), as specified in Table 3 (Watchdog Timeout). The timer clears on any rising or falling edge at WDI and expires only if WDI remains static beyond this period. The MAX6865UK42D1L+T asserts RESET for the 10ms reset timeout upon expiry.

What is the function of Pin 4 (WDI) on the MAX6865UK42D1L+T?

Pin 4 (WDI) is the watchdog input of the MAX6865UK42D1L+T. It monitors µP activity: a rising or falling edge clears the internal watchdog timer, while static high or low states longer than 209s (typ) trigger a reset. WDI accepts CMOS logic levels (VIH = 0.7×VCC, VIL = 0.3×VCC) and has 20nA input current - no external pullup/down is required for MAX6865UK42D1L+T operation.

Is the MAX6865UK42D1L+T pin-compatible with other MAX68xx devices?

The MAX6865UK42D1L+T shares the same 5-pin SOT23-5 pinout as MAX6864/MAX6866/MAX6867/MAX6869 variants but differs from MAX6861–MAX6863 (which use CT instead of WDI) and MAX6854–MAX6856 (which lack WDI). Pin compatibility is limited to the MAX6864–MAX6869 family; substitution outside this group requires PCB revision due to functional pin mapping differences.

What is the minimum operating voltage for guaranteed RESET assertion in the MAX6865UK42D1L+T?

The MAX6865UK42D1L+T guarantees valid RESET assertion down to VCC = +1.1V, as stated in the Electrical Characteristics table under "Guaranteed Reset Valid to VCC = +1.1V". Below this voltage, RESET may become indeterminate. This specification ensures reliable brownout protection in deeply discharged battery scenarios - a key design feature of the MAX6865UK42D1L+T.