Analog Devices Inc./Maxim Integrated MAX6861UK24+T

Overview

MAX6861UK24+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 2.4V reset threshold (±2.5%), pin-selectable 10ms/150ms minimum reset timeout, active-low push-pull RESET output, and manual reset (MR) input. It monitors VCC in battery-powered medical and portable electronics to ensure reliable power-on reset and brownout protection.

For engineers reviewing the MAX6861UK24+T datasheet, MAX6861UK24+T pinout, MAX6861UK24+T application, or MAX6861UK24+T equivalent, key selection criteria include its 2.4V threshold accuracy, CT-pin programmable reset delay, guaranteed RESET validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), and compatibility with low-voltage µP systems operating from 1.2V to 5.5V.

Technical Context

The MAX6861UK24+T integrates a precision voltage monitor, manual reset latch, and reset timeout generator-no watchdog timer or WDI input. Its CT pin selects between two fixed timeout options (D1 = 10ms min or D3 = 150ms min), enabling design flexibility without external timing components.

It asserts an active-low push-pull RESET when VCC falls below 2.4V (with 0.5% hysteresis), holds RESET for the selected timeout after VCC recovers, and guarantees valid output down to VCC = +1.1V. MR is internally pulled up to VCC via 10kΩ and accepts CMOS-level logic.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, -40°C to +85°C industrial temperature range.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3836K24DBVR and STM6315SW24DX6F, the MAX6861UK24+T uniquely combines ultra-low 170nA ICC, pin-selectable 10ms/150ms timeout, and integrated MR-enabling longer battery life and greater flexibility in compact medical and portable designs.

Availability

MAX6861UK24+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered instrumentation, and low-power IoT edge sensors requiring stable component supply across extended production lifecycles.

Supply support for MAX6861UK24+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, sensing, and interface applications in industrial, medical, and communications markets.

The MAX6854–MAX6869 family delivers nanopower supervision for space-constrained, battery-critical systems-specifically engineered to extend runtime while guaranteeing robust reset behavior under brownout and transient conditions.

FAQ

What is the exact reset threshold voltage of the MAX6861UK24+T?

The MAX6861UK24+T has a factory-trimmed reset threshold of 2.4V with ±2.5% tolerance over -40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "24" corresponds to VTH = 2.4V nominal. The device guarantees valid RESET assertion down to VCC = +1.1V, making it suitable for low-voltage brownout detection in the MAX6861UK24+T application space.

How does the CT pin configure the reset timeout on the MAX6861UK24+T?

On the MAX6861UK24+T, the CT pin selects between two minimum reset timeout periods: connecting CT to GND selects D1 = 10ms (min), while connecting CT to VCC selects D3 = 150ms (min). This configuration is defined in Table 1 and the MAX6861/MAX6862/MAX6863 Pin Description section. The timeout period remains fixed during assertion and updates only after the current timeout expires-ensuring predictable behavior in the MAX6861UK24+T timing sequence.

Does the MAX6861UK24+T include a watchdog timer function?

No, the MAX6861UK24+T does not include a watchdog timer. It belongs to the MAX6861/MAX6862/MAX6863 subgroup, which features manual reset (MR) and pin-selectable timeout but omits the WDI input and watchdog circuitry found in MAX6864–MAX6869 variants. The MAX6861UK24+T datasheet explicitly states "No watchdog timer option" in the Selector Guide and Functional Diagram-confirming its role as a dedicated voltage supervisor with configurable reset delay.

What is the RESET output type and drive capability of the MAX6861UK24+T?

The MAX6861UK24+T provides an active-low push-pull RESET output. It sinks ≥1.2mA at VCC ≥ 2.12V (VOL ≤ 0.3V) and sources ≥500µA at VCC ≥ 2.38V (VOH ≥ 0.8 × VCC). This eliminates the need for an external pullup resistor and allows direct connection to standard µP reset inputs. The push-pull architecture ensures fast, deterministic transitions critical for reliable startup in the MAX6861UK24+T application context.

Is the MAX6861UK24+T pin-compatible with other supervisory ICs?

Yes, the MAX6861UK24+T is pin-compatible with the TPS3836/TPS3837/TPS3838 series per the datasheet's Features section. All share the same 5-pin SOT23 footprint and identical pin assignments (CT/MR/GND/RESET/VCC), enabling drop-in replacement in existing layouts-provided the external circuitry (e.g., pullups, timeouts) aligns with the MAX6861UK24+T's push-pull RESET and CT-selectable timeout behavior.