Analog Devices Inc./Maxim Integrated MAX6865UK36D1S+T

Overview

The MAX6865UK36D1S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, combining voltage monitoring (3.600V factory-trimmed reset threshold), manual reset input (MR), and watchdog timer (3.3s typical timeout) with ultra-low 170nA typical supply current. It asserts an active-high push-pull RESET output during VCC brownout, MR assertion, or watchdog timeout, and holds reset for 10ms minimum after recovery - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK36D1S+T datasheet, MAX6865UK36D1S+T pinout, MAX6865UK36D1S+T application, or MAX6865UK36D1S+T equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), pin-selectable reset timeout options, and compatibility with low-voltage µP systems operating from 1.2V to 5.5V.

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 and expires if WDI remains static beyond 3.3s (typ). The internal 10kΩ MR pullup and glitch rejection (200ns) enable robust manual reset handling without external components.

The active-high push-pull RESET output delivers VOH ≥ 0.8×VCC at ISOURCE = 500µA (VCC ≥ 2.38V) and VOL ≤ 0.3V at ISINK = 1.2mA (VCC ≥ 2.38V), ensuring reliable interface with modern low-voltage microcontrollers. Reset assertion timing includes tRD ≤ 40µs (VCC fall) and tMRD = 250ns (MR-to-reset delay).

Key Specifications

Pinout & Package

Package: 5-pin SOT23 (lead-free, +T suffix), footprint-compatible with industry-standard 5-lead SOT-23 layouts and reflow-process ready.

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 MAX6865UK36D1S+T uniquely combines ultra-low 170nA ICC, 3.6V precision threshold, active-high push-pull RESET, MR input, and 3.3s watchdog - making it the sole option meeting full functional and power requirements for next-gen portable medical electronics.

Availability

MAX6865UK36D1S+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitoring devices, and MP3 players requiring stable component supply, long-term lifecycle support, and lead-free compliance.

Supply support for MAX6865UK36D1S+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 consumer systems.

The MAX6854–MAX6869 family was engineered specifically for ultra-low-power microprocessor supervision in battery-constrained portable medical and handheld electronics, emphasizing nanoscale ICC, guaranteed low-VCC reset validity, and integrated watchdog reliability.

FAQ

What is the exact reset threshold voltage of the MAX6865UK36D1S+T?

The MAX6865UK36D1S+T features a factory-trimmed reset threshold of 3.600V, with ±2.5% tolerance 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 "36" corresponds to VTH = 3.600V. The MAX6865UK36D1S+T maintains this accuracy without external calibration or trimming components.

Does the MAX6865UK36D1S+T include a watchdog timer, and what is its timeout?

Yes, the MAX6865UK36D1S+T includes a watchdog timer with a typical timeout of 3.3 seconds, indicated by the "S" suffix in the part number. Per Table 3 (Watchdog Timeout), the S-suffix provides min/typ/max values of 1.5s/3.3s/7.75s. The timer clears on any rising or falling edge at the WDI pin and expires only if WDI remains static beyond this period - a key feature distinguishing it from basic supervisors like the MAX6369.

What type of reset output does the MAX6865UK36D1S+T provide?

The MAX6865UK36D1S+T provides an active-high push-pull RESET output (Pin 1), as confirmed in the MAX6864/MAX6865/MAX6866 Pin Description section. This means RESET drives high (≥0.8×VCC) when asserted and low (≤0.3V) when deasserted - eliminating the need for an external pullup resistor and enabling direct connection to µP reset inputs requiring active-high assertion.

What is the minimum reset timeout period for the MAX6865UK36D1S+T?

The MAX6865UK36D1S+T has a minimum reset timeout period of 10ms, denoted by the "D1" suffix. Table 4 (Reset Timeout Periods) specifies D1 as 10ms (min), 15ms (typ), and 25ms (max). This fixed timeout begins after VCC rises above the 3.600V threshold or MR is deasserted, ensuring sufficient hold time for µP internal initialization before release.

Is the MAX6865UK36D1S+T compatible with 1.8V microcontrollers?

Yes, the MAX6865UK36D1S+T operates across 1.2V to 5.5V and guarantees valid RESET output down to VCC = +1.1V. Its VOH ≥ 0.8×VCC at ISOURCE = 500µA (VCC ≥ 2.38V) and VOL ≤ 0.3V at ISINK = 1.2mA (VCC ≥ 2.38V) ensure interoperability with 1.8V µPs. At VCC = 1.8V, VOH ≥ 1.44V meets standard 1.8V CMOS VIH (≥0.7×VDD), confirming reliable logic-level compatibility.