Analog Devices Inc./Maxim Integrated MAX6861UK29+T

Overview

MAX6861UK29+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 2.925V reset threshold (suffix '29'), and pin-selectable 10ms/150ms minimum reset timeout via CT input. It monitors VCC, accepts manual reset (MR), and asserts active-low push-pull RESET during brownout, power-up, or MR assertion - used in glucose monitors and portable medical devices.

For engineers reviewing the MAX6861UK29+T datasheet, MAX6861UK29+T pinout, MAX6861UK29+T application, or MAX6861UK29+T equivalent, this page delivers verified electrical specs, validated pin functions, confirmed timing behavior at VCC ≥ 1.1V, and real-world substitution guidance for battery-powered µP reset supervision.

Technical Context

The MAX6861UK29+T implements a precision voltage monitor with ±2.5% reset threshold tolerance over -40°C to +85°C, guaranteed reset validity down to VCC = 1.1V, and immunity to VCC transients ≤40µs at 100mV overdrive. Its internal 10kΩ MR pullup enables direct CMOS switch interfacing without external components.

Reset assertion is triggered by VCC falling below 2.925V, MR low pulse ≥1µs, or CT logic level selection (low = D1 timeout, high = D3 timeout). The device uses BiCMOS process (2848 transistors) and requires no external capacitors beyond standard 0.1µF VCC bypass.

Key Specifications

Pinout & Package

5-pin SOT23-5 package (2.9mm × 1.6mm, 0.95mm height), lead-free per +T suffix, rated for -40°C to +85°C operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3836K29DBVR and ADM6806-29ARTZ-R7, the MAX6861UK29+T uniquely combines 170nA ICC, pin-selectable 10ms/150ms timeout, and push-pull RESET - enabling longer battery life, flexible timing, and simplified board layout in portable medical and consumer electronics.

Availability

MAX6861UK29+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, and portable audio equipment requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.

Supply support for MAX6861UK29+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 interface applications in industrial, medical, and communications systems.

The MAX6861UK29+T belongs to the nanopower µP supervisory family, engineered specifically for battery-critical applications demanding sub-µA quiescent current, guaranteed low-VCC reset validity, and minimal external components.

FAQ

What is the exact reset threshold voltage of the MAX6861UK29+T?

The MAX6861UK29+T has a factory-trimmed reset threshold voltage of 2.925V, with ±2.5% tolerance over temperature (-40°C to +85°C). This value is defined by the '29' suffix in the part number and is confirmed in Table 2 (Threshold Suffix Guide) of the official datasheet. The MAX6861UK29+T asserts RESET when VCC falls below this threshold and holds it for the selected timeout period.

How does the CT pin configure reset timeout on the MAX6861UK29+T?

The CT pin on the MAX6861UK29+T selects between two minimum reset timeout periods: logic low (≤0.2×VCC) configures 10ms (D1), and logic high (≥0.8×VCC) configures 150ms (D3). This selection is latched at reset deassertion and remains active until next reset event. The MAX6861UK29+T does not include watchdog or WDI functionality - CT is its only programmable timing feature.

Is the MAX6861UK29+T pin-compatible with other supervisory ICs?

Yes, the MAX6861UK29+T is pin-compatible with the TPS3836/TPS3837/TPS3838 series in the 5-pin SOT23 package. Pin mapping (VCC, GND, MR, RESET, CT) aligns functionally with TPS3836's VCC, GND, MR, RESET, and SENSE pins - though CT serves a different purpose (timeout select vs. sense input). Layout reuse is feasible, but CT must be tied appropriately (not left floating) for correct MAX6861UK29+T operation.

What is the minimum VCC voltage at which MAX6861UK29+T guarantees valid RESET output?

The MAX6861UK29+T guarantees valid RESET output down to VCC = 1.1V, as specified in the Electrical Characteristics table. At VCC ≥ 1.1V and ISINK = 50µA, VOL is guaranteed ≤ 0.3V. Below 1.1V, RESET may become indeterminate - a key differentiator from higher-threshold supervisors and critical for detecting end-of-life battery conditions in medical devices using the MAX6861UK29+T.

Does the MAX6861UK29+T include a watchdog timer function?

No, the MAX6861UK29+T does not include a watchdog timer. It belongs to the MAX6861/MAX6862/MAX6863 subgroup, which provides manual reset (MR) and pin-selectable reset timeout (CT) but omits WDI and watchdog circuitry. Watchdog capability is exclusive to MAX6864–MAX6869 variants. The MAX6861UK29+T is strictly a voltage-monitoring and manual-reset supervisory IC with no watchdog input or timeout monitoring.