Analog Devices Inc./Maxim Integrated MAX6865UK32D3S+T

Overview

The MAX6865UK32D3S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, combining voltage monitoring (3.200V reset threshold), manual reset input (MR), and watchdog timer (209s typical timeout) 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 guarantees valid reset operation down to VCC = +1.1V - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK32D3S+T datasheet, MAX6865UK32D3S+T pinout, MAX6865UK32D3S+T application, or MAX6865UK32D3S+T equivalent, key selection criteria include its factory-trimmed 3.200V reset threshold, 150ms minimum reset timeout (D3), S-suffix 3.3s/209s watchdog option, active-high push-pull output, and guaranteed operation at VCC ≥ 1.1V in low-power 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 and expires if WDI remains static beyond 209s (typ). The internal reset timeout generator provides fixed 150ms (min) assertion after VCC recovery or MR release.

Its active-high push-pull RESET output drives high with VOH ≥ 0.8×VCC (ISOURCE = 500µA) and sinks low with VOL ≤ 0.3V (ISINK = 1.2mA), eliminating external pullup requirements. Immunity to short VCC transients (<40µs at 100mV overdrive) ensures robust operation in noisy portable environments.

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 MAX6864UK32D3S+T and TPS3836K33DBVR, the MAX6865UK32D3S+T uniquely delivers active-high push-pull RESET, 170nA ultra-low ICC, and integrated 209s watchdog - making it optimal for space-constrained, battery-critical medical wearables requiring deterministic reset signaling without external components.

Availability

MAX6865UK32D3S+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign recorders, handheld diagnostic tools, and low-power wearable sensors requiring stable component supply across extended production lifecycles.

Supply support for MAX6865UK32D3S+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 demanding industrial, medical, and communications applications.

The MAX6865UK32D3S+T belongs to the MAX68xx nanopower supervisory family, engineered specifically for ultra-low-power, battery-operated medical and portable electronics requiring guaranteed reset validity down to 1.1V and integrated watchdog protection.

FAQ

What is the exact reset threshold voltage of the MAX6865UK32D3S+T?

The MAX6865UK32D3S+T has a factory-trimmed reset threshold of 3.200V 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 "32" corresponds to 3.200V nominal. The device guarantees reliable detection of brownout on standard 3.3V rails while maintaining margin against ripple and noise.

Does the MAX6865UK32D3S+T include a watchdog timer, and what is its timeout?

Yes, the MAX6865UK32D3S+T includes a watchdog timer with a typical timeout of 209s, indicated by the "S" suffix in the part number. As specified in Table 3 (Watchdog Timeout), the S-suffix provides 3.3s (min) / 209s (typ) / 487s (max) timeout. The timer clears on any WDI edge and triggers reset if WDI remains static beyond this period - critical for detecting firmware hangs in medical firmware.

What type of RESET output does the MAX6865UK32D3S+T provide?

The MAX6865UK32D3S+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 to release the microprocessor and low to assert reset - eliminating the need for an external pullup resistor and simplifying interface to µPs with active-high reset inputs.

What is the minimum reset timeout period for the MAX6865UK32D3S+T?

The MAX6865UK32D3S+T has a minimum reset timeout period of 150ms, denoted by the "D3" suffix per Table 4 (Reset Timeout Periods). This fixed timeout ensures the microprocessor completes power-up initialization and clock stabilization before reset deassertion, preventing premature code execution in battery-powered medical devices.

Is the MAX6865UK32D3S+T compatible with 1.8V supply systems?

Yes, the MAX6865UK32D3S+T operates across 1.2V to 5.5V, and its 170nA typical supply current is specified at VCC = 1.8V. Its RESET output maintains VOH ≥ 0.8×VCC and VOL ≤ 0.3V across this range, ensuring compatibility with 1.8V µPs. The 3.200V threshold applies only to the monitored VCC rail - not the device's own supply - so it can supervise higher rails while being powered from lower ones.