Analog Devices Inc./Maxim Integrated MAX6865UK23D2S+T

Overview

The MAX6865UK23D2S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, combining voltage monitoring (reset threshold = +2.313V), manual reset input (MR), and watchdog timer (timeout = 3.3s typ) with ultra-low 170nA typical supply current. It asserts an active-high push-pull RESET signal during VCC brownout, MR assertion, or watchdog timeout, and holds reset for 40ms minimum after recovery - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK23D2S+T datasheet, MAX6865UK23D2S+T pinout, MAX6865UK23D2S+T application, or MAX6865UK23D2S+T equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to sub-40µs VCC transients, fixed 40ms reset timeout, and compatibility with 1.2V–5.5V supply rails in space-constrained embedded systems.

Technical Context

This device implements a precision bandgap-based voltage monitor with ±2.5% threshold accuracy over -40°C to +85°C, coupled with a digital watchdog timer that clears on any WDI edge (rising or falling) and expires if WDI remains static beyond 3.3s (typ). Its internal 10kΩ MR pullup and glitch rejection (200ns) eliminate external components for basic reset initiation.

The push-pull active-high RESET output drives directly to VCC with VOH ≥ 0.8×VCC (at ISOURCE = 500µA) and VOL ≤ 0.3V (at ISINK = 1.2mA), ensuring robust logic-level compatibility across 1.71V–5.5V domains without external level-shifting circuitry.

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 MAX6864UK23D2S+T, the MAX6865UK23D2S+T offers identical supervision core but adds active-high push-pull RESET - simplifying interface to µPs requiring high-asserted reset. Versus TPS3836K33DBVR, it delivers 20× lower ICC and integrated watchdog, enabling robust, long-life portable medical and IoT applications.

Availability

MAX6865UK23D2S+T is available at Aetrix Electronics and suitable for portable medical devices, wireless sensor nodes, industrial handheld terminals, and battery-powered instrumentation requiring stable component supply across extended temperature ranges.

Supply support for MAX6865UK23D2S+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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, medical, and communications markets.

The MAX6854–MAX6869 family was designed specifically for ultra-low-power microprocessor supervision in battery-critical applications, integrating precision voltage monitoring, manual reset, and watchdog functionality into minimal-area SOT23 packages.

FAQ

What is the exact reset threshold voltage of the MAX6865UK23D2S+T?

The MAX6865UK23D2S+T has a factory-trimmed reset threshold of +2.313V, 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 "23" corresponds to VTH = +2.313V (min +2.255V, max +2.371V). The threshold is referenced to the VCC pin and remains stable across temperature per the normalized VTH vs. temperature curve (Figure MAX6854 toc06).

Does the MAX6865UK23D2S+T support active-high or active-low reset output?

The MAX6865UK23D2S+T features an active-high push-pull RESET output (pin 1), as confirmed in the MAX6864/MAX6865/MAX6866 Pin Description table (page 8) and Selector Guide (page 16). When asserted, RESET drives high to VCC; when deasserted, it drives low. This eliminates need for external pullup resistors and ensures direct compatibility with µPs requiring high-asserted reset inputs.

What is the watchdog timeout behavior of the MAX6865UK23D2S+T?

The MAX6865UK23D2S+T implements a watchdog timer with 3.3s typical timeout (S suffix), as specified in Table 3 (Watchdog Timeout). The timer clears on any rising or falling edge at WDI (pin 4) and expires only if WDI remains static beyond 3.3s. Upon expiration, it asserts RESET for the full 40ms reset timeout period (D2 option), then deasserts - providing deterministic firmware hang detection without false triggers from short pulses.

Can the MAX6865UK23D2S+T operate down to 1.2V supply voltage?

Yes, the MAX6865UK23D2S+T operates across VCC = 1.2V to 5.5V, with guaranteed reset functionality down to VCC = +1.1V (per Electrical Characteristics table, page 2). At 1.2V, supply current is 190nA (typ), reset threshold remains accurate, and RESET output maintains VOH ≥ 0.8×VCC and VOL ≤ 0.3V - enabling reliable supervision in single-cell alkaline or lithium primary battery systems.

Is the MAX6865UK23D2S+T pin-compatible with other devices in the MAX68xx family?

The MAX6865UK23D2S+T uses the standard 5-pin SOT23-5 package and shares identical pinout with MAX6864/MAX6866 (pin 1 = RESET, pin 2 = GND, pin 3 = MR, pin 4 = WDI, pin 5 = VCC), as shown in the Pin Configurations diagram (page 15). It is not pin-compatible with MAX6861–MAX6863 (which use CT instead of WDI) or MAX6854–MAX6856 (which lack WDI), but drop-in replacement is possible within the MAX6864–MAX6866 subgroup.