Analog Devices Inc./Maxim Integrated MAX6865UK20D6L+T

Overview

The MAX6865UK20D6L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, combining voltage monitoring (2.000V reset threshold), manual reset input (MR), and watchdog timer (209s typical timeout) with ultra-low 170nA supply current. It asserts an active-high push-pull RESET output during VCC brownout, MR assertion, or watchdog timeout, and holds reset for 1200ms minimum after recovery - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK20D6L+T datasheet, MAX6865UK20D6L+T pinout, MAX6865UK20D6L+T application, or MAX6865UK20D6L+T equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), fixed 1200ms reset timeout, and 209s watchdog period - all critical for low-power embedded safety-critical systems.

Technical Context

The MAX6865UK20D6L+T implements a dual-monitoring architecture: a precision bandgap-based voltage detector triggers reset when VCC falls below 2.000V ±2.5%, while a digital watchdog timer monitors WDI activity and expires if no edge occurs within 209s (typ). Its internal 10kΩ MR pullup and glitch rejection (200ns) enable robust manual reset without external components.

Reset assertion is synchronized across both detection paths - VCC drop, MR low, or WDI timeout - and deassertion is delayed by a fixed 1200ms timeout after VCC exceeds threshold and MR is released. The push-pull active-high RESET output drives directly to VCC, eliminating need for external pullups and ensuring clean logic-level compatibility with µP reset inputs.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, -40°C to +85°C operating range.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6865UK20D6L+T, MAX6864UK20D6S+T trades longer watchdog coverage for faster fault response, while TPS3836K20DBVR sacrifices watchdog capability and push-pull drive to reduce cost - making MAX6865UK20D6L+T optimal for safety-critical, long-interval, low-power monitoring.

Availability

MAX6865UK20D6L+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered instrumentation, and industrial handheld equipment requiring stable component supply with guaranteed long-term availability.

Supply support for MAX6865UK20D6L+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 interface applications in industrial, medical, and communications markets.

The MAX6854–MAX6869 family delivers nanopower supervisory functionality for battery-critical systems - engineered specifically to extend runtime while guaranteeing fail-safe reset behavior under brownout, noise, and software failure conditions.

FAQ

What is the exact reset threshold voltage of the MAX6865UK20D6L+T?

The MAX6865UK20D6L+T has a factory-trimmed reset threshold of +2.000V with ±2.5% tolerance over temperature (-40°C to +85°C). This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "20" corresponds to 2.000V nominal. The device guarantees valid reset assertion down to VCC = +1.1V, making it suitable for deep-brownout detection in single-cell Li-ion systems.

Does the MAX6865UK20D6L+T support active-high or active-low reset output?

The MAX6865UK20D6L+T features an active-high push-pull RESET output, as confirmed by its pin description (Pin 1 = RESET, active-high) and Selector Guide. Unlike open-drain or active-low variants, this configuration drives high during reset assertion and requires no external pullup resistor - simplifying interface to µPs with high-active reset inputs like many ARM Cortex-M series devices.

What is the watchdog timeout period for the MAX6865UK20D6L+T?

The MAX6865UK20D6L+T uses the "L" watchdog suffix, providing a typical timeout period of 209s with a guaranteed range of 95s to 487s over temperature. This long interval is optimized for infrequent-event systems such as remote environmental sensors or medical loggers where firmware execution cycles span minutes - distinct from the "S" (3.3s) option used in faster-response applications.

How does the MAX6865UK20D6L+T handle manual reset input (MR) noise?

The MAX6865UK20D6L+T incorporates 200ns glitch rejection on the MR pin and includes an internal 10kΩ pullup to VCC, eliminating need for external debounce circuitry. MR accepts standard CMOS logic levels and remains immune to transients shorter than 200ns - a key advantage in handheld devices with mechanical reset switches exposed to ESD or contact bounce.

Is the MAX6865UK20D6L+T pin-compatible with other devices in the MAX68xx family?

The MAX6865UK20D6L+T shares the identical 5-pin SOT23-5 footprint and pinout (VCC, WDI, MR, GND, RESET) with MAX6864/MAX6866/MAX6867–MAX6869 variants. However, it is not pin-compatible with MAX6854–MAX6863 series, which lack WDI or use CT pin instead - confirming direct substitution only among MAX6864–MAX6869 with matching reset output polarity and timeout options.