Analog Devices Inc./Maxim Integrated MAX6865UK41D6S+T

Overview

The MAX6865UK41D6S+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 4.100V reset threshold (±2.5%), 1200ms minimum reset timeout, manual reset input (MR), and watchdog timer with 209s typical timeout. It monitors VCC in battery-powered medical and portable electronics to ensure reliable power-on reset and fault recovery.

For engineers reviewing the MAX6865UK41D6S+T datasheet, MAX6865UK41D6S+T pinout, MAX6865UK41D6S+T application, or MAX6865UK41D6S+T equivalent, this device serves as a critical fail-safe for low-voltage µP systems where supply stability, transient immunity, and long watchdog intervals are essential - especially in glucose monitors and patient monitoring equipment requiring guaranteed reset validity down to VCC = +1.1V.

Technical Context

The MAX6865UK41D6S+T integrates voltage monitoring, a 209s typical watchdog timer, and active-low manual reset in a single BiCMOS IC. Its reset assertion is triggered by VCC falling below 4.100V, MR pull-down, or WDI inactivity exceeding watchdog timeout - with reset held for ≥600ms (min) after recovery.

It uses internal 10kΩ MR pull-up and supports push-pull active-high RESET output. The watchdog clears on any WDI edge (≥150ns pulse width), and the device remains functional down to VCC = +1.1V, ensuring robust operation during brownout conditions.

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 MAX6864UK41D6S+T and TPS3838K33DBVR, the MAX6865UK41D6S+T uniquely delivers 4.1V precision monitoring, 209s watchdog, and active-high RESET in a single 170nA solution - making it optimal for next-gen portable medical devices demanding both ultra-low power and long-interval fault detection.

Availability

MAX6865UK41D6S+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitoring systems, industrial handheld terminals, and smart wearables requiring stable component supply, long-term lifecycle support, and lead-free compliance.

Supply support for MAX6865UK41D6S+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 applications.

The MAX6854–MAX6869 family was designed specifically for ultra-low-power microprocessor supervision in battery-critical systems - emphasizing nanopower operation, precise voltage thresholds, and integrated watchdog functionality without external components.

FAQ

What is the exact reset threshold voltage of the MAX6865UK41D6S+T?

The MAX6865UK41D6S+T has a factory-trimmed reset threshold voltage of +4.100V, with guaranteed tolerance of ±2.5% over the -40°C to +85°C temperature range. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "41" corresponds to 4.100V nominal. The device asserts reset when VCC falls below this threshold and holds reset for ≥600ms after VCC rises above it.

Does the MAX6865UK41D6S+T support active-high or active-low reset output?

The MAX6865UK41D6S+T features an active-high push-pull RESET output, as confirmed by its pin description (Pin 1 = RESET, "Active-High Push-Pull Reset Output") and Selector Guide entry. This means RESET goes high during reset assertion and returns low upon deassertion - directly compatible with µPs requiring active-high reset inputs without external inverters or pull-up resistors.

What is the watchdog timeout period for the MAX6865UK41D6S+T?

The MAX6865UK41D6S+T uses the "L" watchdog suffix, providing a typical timeout period of 209s, with min/max values of 95s and 487s respectively. This long interval is intended for applications with extended firmware loops or infrequent activity, such as patient monitoring devices that perform background sensor sampling without CPU intervention for several minutes.

Can the MAX6865UK41D6S+T operate reliably at VCC = +1.1V?

Yes - the MAX6865UK41D6S+T guarantees valid reset output functionality down to VCC = +1.1V, as explicitly stated in the "Guaranteed Reset Valid to VCC = +1.1V" feature and Electrical Characteristics table. Below this voltage, RESET behavior is not specified, but the device continues to monitor and assert reset until VCC drops below operational limits.

Is an external pull-up resistor required for the MR input on the MAX6865UK41D6S+T?

No - the MAX6865UK41D6S+T includes an internal 10kΩ pull-up resistor from MR to VCC, as documented in the Pin Description and Detailed Description sections. This eliminates the need for external components when implementing manual reset with a momentary switch to GND, simplifying layout and reducing BOM count.