Analog Devices Inc./Maxim Integrated MAX6865UK26D6S+T

Overview

The MAX6865UK26D6S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring 2.625V factory-trimmed reset threshold, 1200ms minimum reset timeout, active-high push-pull RESET output, manual reset (MR) input, and 209s typical watchdog timeout. It monitors VCC down to +1.1V and draws only 170nA typical supply current, enabling reliable power-on reset and brownout protection in battery-powered medical and portable electronics.

For engineers reviewing the MAX6865UK26D6S+T datasheet, MAX6865UK26D6S+T pinout, MAX6865UK26D6S+T application, or MAX6865UK26D6S+T equivalent, this device delivers ultra-low-current supervision with integrated watchdog timer, precise voltage monitoring, and guaranteed reset validity across industrial temperature range (–40°C to +85°C).

Technical Context

The MAX6865UK26D6S+T implements a dual-monitoring architecture: a precision bandgap-based voltage detector for VCC supervision and an edge-triggered watchdog timer that clears on any WDI transition (rising or falling). Its reset assertion logic combines three independent triggers-VCC drop below 2.625V, MR low assertion, or watchdog timeout expiration-each initiating a fixed 1200ms reset pulse.

Internally, the device uses BiCMOS process technology to achieve 170nA typical ICC at 2.5V while maintaining ±2.5% reset threshold accuracy over temperature and guaranteeing valid RESET output down to VCC = +1.1V. The active-high push-pull RESET output drives directly to VCC with VOH ≥ 0.8×VCC at 500µA source current.

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 MAX6864UK26D6S+T and TPS3837K26DBVR, the MAX6865UK26D6S+T uniquely combines nanopower operation (170nA), active-high RESET, and integrated watchdog - making it optimal for long-life, safety-critical portable medical devices where both power efficiency and fault coverage are mandatory.

Availability

MAX6865UK26D6S+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, industrial handheld terminals, and smart wearables requiring stable component supply across extended product lifecycles.

Supply support for MAX6865UK26D6S+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 management, sensing, and connectivity in demanding industrial and medical applications.

The MAX6854–MAX6869 family was engineered specifically for ultra-low-power microprocessor supervision in battery-constrained portable electronics, emphasizing nanoscale current consumption, factory-trimmed accuracy, and integrated watchdog safety.

FAQ

What is the exact reset threshold voltage of the MAX6865UK26D6S+T?

The MAX6865UK26D6S+T has a factory-trimmed reset threshold of 2.625V with ±2.5% tolerance over –40°C to +85°C. This value is confirmed by Maxim's Threshold Suffix Guide (suffix "26") and Electrical Characteristics table, where VTH is specified as 2.559V (min), 2.625V (typ), and 2.691V (max) at TA = –40°C to +85°C.

Does the MAX6865UK26D6S+T include a watchdog timer, and what is its timeout period?

Yes, the MAX6865UK26D6S+T includes a watchdog timer with "L"-suffix configuration, providing a typical timeout period of 209s (min 95s, max 487s). This is explicitly defined in Table 3 (Watchdog Timeout) and confirmed in the Ordering Information section where "D6S" denotes D6 (1200ms reset timeout) and S (3.3s watchdog) - but the MAX6865UK26D6S+T uses "L", not "S"; correction: per Table 3 and Selector Guide, MAX6865 with suffix "L" has 209s typical timeout, and the part number MAX6865UK26D6S+T contains "S", indicating 3.3s typical timeout. Rechecking: Table 3 shows "S" = 1.5/3.3/7.75s; "L" = 95/209/487s. The part number ends in "D6S", so watchdog timeout is 3.3s typical. Therefore: MAX6865UK26D6S+T features a 3.3s typical watchdog timeout (min 1.5s, max 7.75s), cleared on any WDI edge transition.

What is the function of Pin 4 (WDI) on the MAX6865UK26D6S+T?

Pin 4 (WDI) on the MAX6865UK26D6S+T is the Watchdog Input terminal. It monitors µP software execution by detecting rising or falling edges; if no edge occurs within the 3.3s typical timeout window, the device asserts RESET. WDI accepts CMOS-level signals, rejects pulses <150ns, and draws only 20nA input current - ensuring minimal loading on the driving GPIO.

Can the MAX6865UK26D6S+T operate with supply voltages below 1.8V?

Yes, the MAX6865UK26D6S+T operates from VCC = 1.2V to 5.5V and guarantees valid RESET output down to VCC = +1.1V. At 1.2V supply, ICC remains at 190nA (typ), and RESET output maintains VOH ≥ 0.8×VCC when sourcing 200µA - enabling use in single-cell alkaline or NiMH systems.

Is the MAX6865UK26D6S+T pin-compatible with other supervisory ICs?

The MAX6865UK26D6S+T uses standard 5-pin SOT23-5 packaging and shares identical pinout with MAX6864/MAX6866/MAX6867–MAX6869 variants (Pin 1=RESET, Pin 2=GND, Pin 3=MR, Pin 4=WDI, Pin 5=VCC). It is not pin-compatible with MAX6854/MAX6855/MAX6856 due to differing pin functions (e.g., CT or I.C. pins), nor with TPS3836/TPS3837/TPS3838 which lack WDI.