Analog Devices Inc./Maxim Integrated MAX6865UK25D5S+T

Overview

The MAX6865UK25D5S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, combining voltage monitoring, manual reset input (MR), and watchdog timer (WDI) functionality. It asserts an active-high push-pull RESET output when VCC drops below 2.500V (±2.5%), MR is pulled low, or the watchdog expires after 3.3s (typ). Designed for ultra-low-power systems, it draws only 170nA (typ) at 2.5V and guarantees valid reset operation down to VCC = +1.1V.

For engineers reviewing the MAX6865UK25D5S+T datasheet, MAX6865UK25D5S+T pinout, MAX6865UK25D5S+T application, or MAX6865UK25D5S+T equivalent, key selection criteria include its factory-trimmed 2.5V reset threshold, 300ms minimum reset timeout (D5), 3.3s watchdog period (S suffix), active-high push-pull RESET output, and compatibility with battery-powered medical and portable electronics requiring guaranteed reset assertion below 1.1V.

Technical Context

The MAX6865UK25D5S+T implements a precision bandgap-based voltage monitor with 2.5% threshold tolerance and 0.5% hysteresis, ensuring immunity to short VCC transients (e.g., ≤40µs at 100mV overdrive). Its watchdog timer clears on any WDI edge and times out after 3.3s (typ), with normalized drift <±15% over –40°C to +85°C.

This device integrates a 10kΩ internal MR pullup, supports CMOS-logic-level MR/WDI inputs (VIH = 0.7×VCC, VIL = 0.3×VCC), and features glitch rejection of 200ns on MR and 150ns on WDI. The push-pull RESET output delivers VOH ≥ 0.8×VCC (ISOURCE = 500µA) and VOL ≤ 0.3V (ISINK = 1.2mA) across its full 1.2V–5.5V supply range.

Key Specifications

Pinout & Package

Package: 5-pin SOT23 (lead-free, +T suffix), footprint-compatible with industry-standard 5-lead SC-70/SOT-23 variants.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK25D5S+T and TPS3837K25DBVR, the MAX6865UK25D5S+T uniquely delivers active-high reset drive, nanopower operation, and integrated watchdog - making it optimal for next-generation portable medical and wearable designs where reset polarity, battery longevity, and firmware reliability are co-constrained.

Availability

MAX6865UK25D5S+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign loggers, industrial handheld scanners, and smart wearable health trackers requiring stable component supply and long-term lifecycle support.

Supply support for MAX6865UK25D5S+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 MAX6865UK25D5S+T belongs to Maxim's nanopower µP supervisory family, engineered specifically for battery-critical portable medical and consumer electronics demanding guaranteed reset behavior below 1.1V and ultra-low quiescent current.

FAQ

What is the exact reset threshold voltage of the MAX6865UK25D5S+T?

The MAX6865UK25D5S+T has a factory-trimmed reset threshold of +2.500V with ±2.5% tolerance over –40°C to +85°C, as defined by the "25" suffix in its part number per Maxim's Threshold Suffix Guide (Table 2). This value is laser-trimmed during production and does not require external calibration.

Does the MAX6865UK25D5S+T include a watchdog timer, and what is its timeout period?

Yes, the MAX6865UK25D5S+T includes a watchdog timer with a typical timeout period of 3.3 seconds, indicated by the "S" suffix in its part number (Table 3). The timer resets on any rising or falling edge at the WDI pin and triggers RESET if no edge occurs within that period.

What type of RESET output does the MAX6865UK25D5S+T provide, and how is it configured?

The MAX6865UK25D5S+T provides an active-high push-pull RESET output, as confirmed by its position in the Selector Guide (row MAX6865) and Pin Description section. It drives high to VCC when asserted and low to GND when deasserted - requiring no external pullup resistor and compatible with µPs accepting active-high reset signals.

What is the minimum supply voltage at which the MAX6865UK25D5S+T guarantees valid RESET operation?

The MAX6865UK25D5S+T guarantees valid RESET output down to VCC = +1.1V, as specified in the Absolute Maximum Ratings and Electrical Characteristics tables. Below this voltage, RESET may become indeterminate, but the device continues asserting RESET until VCC falls further.

How does the MAX6865UK25D5S+T handle manual reset input (MR) debouncing and noise immunity?

The MAX6865UK25D5S+T incorporates 200ns MR input glitch rejection and an internal 10kΩ pullup to VCC. No external capacitor is required for basic debounce; however, in high-noise environments, a 0.1µF capacitor from MR to GND is recommended per the Applications Information section.