Analog Devices Inc./Maxim Integrated MAX6861UK18+T

Overview

The MAX6861UK18+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 1.8V reset threshold (±2.5%), and pin-selectable 10ms/150ms minimum reset timeout. It provides active-low push-pull reset output, manual reset input (MR), and reset timeout selection via CT pin - designed for reliable power-on reset and brownout protection in battery-critical systems.

For engineers reviewing the MAX6861UK18+T datasheet, MAX6861UK18+T pinout, MAX6861UK18+T application, or MAX6861UK18+T equivalent, key selection considerations include its 1.8V V_TH accuracy over -40°C to +85°C, guaranteed reset validity down to V_CC = 1.1V, immunity to short V_CC transients (<40µs at 100mV overdrive), and compatibility with portable medical and handheld electronics requiring minimal quiescent current.

Technical Context

The MAX6861UK18+T integrates voltage monitoring, manual reset assertion, and a fixed-function reset timeout generator - but no watchdog timer (unlike MAX6864–MAX6869). Its CT pin selects between two factory-programmed timeout options (D1 = 10ms min or D3 = 150ms min), with internal timing independent of external components.

Reset assertion occurs when V_CC falls below 1.8V (V_TH ±2.5%), MR is pulled low, or during power-up/brownout; deassertion follows a precise timeout after V_CC rises above V_TH and MR is released. The push-pull active-low RESET output drives to <0.3V at 1.2mA sink (V_CC ≥ 2.38V) and remains valid down to V_CC = 1.1V.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5 (2.9mm × 1.6mm × 1.1mm), lead-free, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3836K33DBVR and STM6315RWX6F, the MAX6861UK18+T delivers the lowest ICC (170nA) and unique pin-selectable timeout - enabling single-BOM flexibility across 10ms/150ms use cases while maintaining 1.8V precision and 1.1V reset validity critical for energy-constrained designs.

Availability

MAX6861UK18+T is available at Aetrix Electronics and suitable for portable medical devices, handheld industrial scanners, wearable health trackers, and smart remote controls requiring stable component supply with long-term lifecycle support.

Supply support for MAX6861UK18+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 MAX6854–MAX6869 family targets ultra-low-power microprocessor supervision in battery-operated equipment, emphasizing nanoscale ICC, factory-trimmed thresholds, and minimal external component count.

FAQ

What is the exact reset threshold voltage of the MAX6861UK18+T?

The MAX6861UK18+T has a factory-trimmed reset threshold of 1.800V with ±2.5% tolerance (1.755V to 1.845V), confirmed in the Threshold Suffix Guide (suffix '18' corresponds to 1.8V). This value is guaranteed over -40°C to +85°C and applies to V_CC falling conditions. The MAX6861UK18+T does not require external calibration to achieve this accuracy.

How do I configure the reset timeout period on the MAX6861UK18+T?

The MAX6861UK18+T uses the CT pin (Pin 1) to select between two minimum reset timeout periods: connect CT to GND for 10ms (D1), or to V_CC for 150ms (D3). This selection is sampled at reset deassertion and remains effective until the next reset event. No external resistor or capacitor is needed - the timing is fully internal and factory-characterized.

Does the MAX6861UK18+T include a watchdog timer function?

No, the MAX6861UK18+T does not include a watchdog timer. It belongs to the MAX6861/MAX6862/MAX6863 subgroup, which provides manual reset (MR) and pin-selectable timeout but omits WDI functionality. Watchdog capability is exclusive to MAX6864–MAX6869 variants. The MAX6861UK18+T relies solely on V_CC monitoring and MR for reset generation.

What is the minimum operating voltage for guaranteed reset functionality in the MAX6861UK18+T?

The MAX6861UK18+T guarantees valid reset assertion down to V_CC = 1.1V, as specified in the Electrical Characteristics table. Below this voltage, reset behavior is not characterized. This 1.1V limit enables robust brownout recovery in deeply discharged battery scenarios where other supervisors may fail to assert reset reliably.

Is the MAX6861UK18+T pin-compatible with other devices in the MAX68xx family?

Yes, the MAX6861UK18+T shares the same 5-pin SOT23-5 footprint and pinout (CT/GND/MR/RESET/V_CC) with MAX6862UK18+T and MAX6863UK18+T. However, it is not pin-compatible with MAX6864–MAX6869 (which substitute WDI for CT) or MAX6854–MAX6856 (which lack CT and have different RESET configurations). Always verify pin function alignment per device variant.