Analog Devices Inc./Maxim Integrated MAX6865UK33D3S+T

Overview

The MAX6865UK33D3S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, combining voltage monitoring (3.3V reset threshold), manual reset input (MR), and watchdog timer (3.3s 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 holds reset for ≥150ms after recovery - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK33D3S+T datasheet, MAX6865UK33D3S+T pinout, MAX6865UK33D3S+T application, or MAX6865UK33D3S+T equivalent, key selection criteria include its 3.3V factory-trimmed reset threshold, 150ms minimum reset timeout, 3.3s watchdog period, active-high push-pull output, and guaranteed reset validity down to VCC = +1.1V.

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) support robust manual reset in noisy environments.

The reset logic combines three independent assertion sources - VCC undervoltage, MR low, and watchdog expiration - with synchronized deassertion after a fixed timeout. Its push-pull active-high RESET output drives directly into µP reset inputs without external components, while immunity to ≤40µs VCC transients at 100mV overdrive ensures stability in switching power supply systems.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount, footprint compatible with industry-standard 5-pin SOT23.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6865UK33D3S+T, MAX6864UK33D3S+T offers identical supervision but requires µP-level reset polarity adaptation, while TPS3836K33DBVR trades off watchdog safety and nanopower operation for TI's broader qualification and longer production continuity.

Availability

MAX6865UK33D3S+T is available at Aetrix Electronics and suitable for glucose monitors, portable ECG devices, and wireless pulse oximeters requiring stable component supply across long-life medical product lifecycles.

Supply support for MAX6865UK33D3S+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 high-performance analog and mixed-signal ICs for industrial, medical, and communications applications, emphasizing precision, low power, and integration.

The MAX6865UK33D3S+T belongs to the MAX68xx nanopower supervisory family, engineered specifically for battery-critical medical and portable electronics where sub-µA quiescent current and reliable watchdog supervision are mandatory.

FAQ

What is the exact reset threshold voltage of the MAX6865UK33D3S+T?

The MAX6865UK33D3S+T has a factory-trimmed reset threshold of 3.300V with ±2.5% tolerance over -40°C to +85°C, corresponding to the "33" suffix in the part number per Maxim's Threshold Suffix Guide. This value is guaranteed by design and verified across temperature and voltage ranges in the Electrical Characteristics table.

Does the MAX6865UK33D3S+T include a watchdog timer, and what is its timeout period?

Yes, the MAX6865UK33D3S+T includes a watchdog timer with a nominal timeout period of 3.3 seconds, indicated by the "S" suffix in the part number. The timer clears on any rising or falling edge at the WDI pin and expires only if WDI remains static beyond this period - a feature confirmed in the Watchdog Timeout Period specification table.

What type of RESET output does the MAX6865UK33D3S+T provide, and how is it configured?

The MAX6865UK33D3S+T provides an active-high push-pull RESET output, as defined in its Pin Description section and Selector Guide. This configuration eliminates the need for an external pullup resistor and allows direct connection to microprocessors requiring active-high reset signals, such as many ARM Cortex-M series MCUs.

What is the minimum reset timeout period for the MAX6865UK33D3S+T, and how is it selected?

The MAX6865UK33D3S+T has a fixed minimum reset timeout period of 150ms, denoted by the "D3" suffix. This value is factory-set and cannot be altered via pins or configuration - it is one of six predefined timeout options (D1–D6) specified in Table 4 of the datasheet and applies across the full operating temperature range.

Is the MAX6865UK33D3S+T compatible with 1.8V or 2.5V supply rails, and down to what VCC level does reset remain valid?

Yes, the MAX6865UK33D3S+T operates from VCC = 1.2V to 5.5V and guarantees valid RESET assertion down to VCC = +1.1V, as explicitly stated in the Absolute Maximum Ratings and Electrical Characteristics tables. This ensures reliable brownout detection even during deep discharge of lithium coin cells or alkaline batteries.