Analog Devices Inc./Maxim Integrated MAX6865UK29D2S+T

Overview

The MAX6865UK29D2S+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 2.925V reset threshold, 40ms minimum reset timeout, and integrated watchdog timer with 3.3s typical timeout. It monitors VCC, responds to manual reset (MR), and asserts active-low push-pull RESET during brownout, power-up, or watchdog expiration - used in battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK29D2S+T datasheet, MAX6865UK29D2S+T pinout, MAX6865UK29D2S+T application, or MAX6865UK29D2S+T equivalent, this page delivers verified electrical parameters, exact pin functions, real-world use cases in low-power medical and handheld systems, and two confirmed alternative parts with documented functional and timing differences.

Technical Context

The MAX6865UK29D2S+T implements a precision voltage monitor with ±2.5% reset threshold accuracy over -40°C to +85°C, guaranteed RESET validity down to VCC = +1.1V, and immunity to VCC transients ≤40µs at 100mV overdrive. Its watchdog timer clears on any WDI edge and expires if WDI remains static beyond 3.3s (typ), triggering a full reset timeout cycle.

This device integrates MR input with 10kΩ internal pullup, 250ns MR-to-reset delay, and 1µs minimum MR pulse width. The push-pull active-low RESET output sinks ≥50µA at 0.3V (VCC ≥ 1.1V) and sources ≥200µA at 0.8×VCC (VCC ≥ 1.71V), enabling direct interface with CMOS µP reset inputs without external components.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK29D2S+T, the MAX6865UK29D2S+T adds CT pin flexibility but shares identical core supervision specs; versus TPS3836K33DBVR, it delivers 9.4× lower ICC, 7.5× shorter reset timeout, and integrated watchdog - critical for portable medical compliance.

Availability

MAX6865UK29D2S+T is available at Aetrix Electronics and suitable for glucose monitors, portable ECG recorders, smart inhalers, and wearable pulse oximeters requiring stable component supply with long-lifecycle support.

Supply support for MAX6865UK29D2S+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, mixed-signal, and power management ICs for demanding industrial, medical, and communications applications.

The MAX68xx family targets ultra-low-power microprocessor supervision in battery-constrained portable medical and handheld electronics, emphasizing nanopower operation, guaranteed brownout behavior, and integrated watchdog reliability.

FAQ

What is the exact reset threshold voltage of the MAX6865UK29D2S+T?

The MAX6865UK29D2S+T has a factory-trimmed reset threshold of 2.925V, with ±2.5% tolerance over -40°C to +85°C. This value is defined by the "29" suffix per Maxim's Threshold Suffix Guide (Table 2), and is measured at VCC falling. The MAX6865UK29D2S+T guarantees valid RESET assertion down to VCC = +1.1V, making it suitable for deep brownout recovery in battery-powered systems.

Does the MAX6865UK29D2S+T include a watchdog timer, and what is its timeout?

Yes, the MAX6865UK29D2S+T includes a watchdog timer with a typical timeout of 3.3s, denoted 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. The MAX6865UK29D2S+T does not support the 209s (L) timeout option - that is reserved for other variants like MAX6865UK29D2L+T.

What is the reset timeout period for the MAX6865UK29D2S+T, and how is it selected?

The MAX6865UK29D2S+T has a fixed 40ms minimum reset timeout, indicated by the "D2" suffix. Unlike MAX6861–MAX6863 variants, it does not feature a CT pin for runtime timeout selection. The timeout is factory-set and unchangeable; the MAX6865UK29D2S+T asserts RESET for ≥40ms after VCC rises above 2.925V and MR is deasserted, ensuring robust µP initialization.

What type of RESET output does the MAX6865UK29D2S+T provide?

The MAX6865UK29D2S+T provides an active-low push-pull RESET output on Pin 1. It drives low (≤0.3V at 50µA sink) when asserted and high (≥0.8×VCC at 200µA source) when deasserted - requiring no external pullup resistor. This differs from open-drain variants (e.g., MAX6856) and active-high push-pull versions (e.g., MAX6865UK29D2S+T is not offered in active-high configuration).

Is the MAX6865UK29D2S+T pin-compatible with other MAX68xx supervisory ICs?

The MAX6865UK29D2S+T uses the standard 5-pin SOT23-5 package 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 MAX6861–MAX6863 (which use Pin 1 = CT) or MAX6854–MAX6856 (which lack WDI). Layout reuse is possible only within the MAX6864–MAX6869 WDI-equipped group.