Analog Devices Inc./Maxim Integrated MAX6861UK20+T

Overview

The MAX6861UK20+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 2.0V reset threshold (±2.5%), and pin-selectable 10ms/150ms (min) 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 MAX6861UK20+T datasheet, MAX6861UK20+T pinout, MAX6861UK20+T application, or MAX6861UK20+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 supervision.

Technical Context

The MAX6861UK20+T integrates voltage monitoring, manual reset input, and a fixed-function reset timeout generator with CT pin selection between two discrete timeout options (D1 = 10ms min, D3 = 150ms min). Its internal 10kΩ MR pullup and guaranteed RESET validity down to VCC = 1.1V enable robust operation in low-voltage brownout conditions.

No watchdog timer or WDI input is present - confirmed by Selector Guide and Pin Description tables. The device uses BiCMOS process (2848 transistors), supports 1.2V–5.5V VCC, and is immune to VCC transients ≤40µs at 100mV overdrive - critical for noisy portable systems.

Key Specifications

Pinout & Package

MAX6861UK20+T is housed in a lead-free 5-pin SOT23 package (JEDEC MO-178AA), measuring 2.9mm × 1.6mm × 1.1mm. Pin 1 is marked with a dot; pin numbering follows standard SOT23 orientation (top view, notch left).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3836K20DBVR and MAX6315US20D3+, the MAX6861UK20+T uniquely combines nanopower operation (170nA), pin-selectable timeout, and integrated MR pullup - making it optimal for long-life, space-constrained medical wearables where every nanoamp and millisecond matters.

Availability

MAX6861UK20+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign monitors, handheld diagnostic tools, and low-power wearable sensors requiring stable component supply across extended production lifecycles.

Supply support for MAX6861UK20+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 industrial, medical, and communications applications, emphasizing low-power, high-reliability performance.

The MAX6861UK20+T belongs to the MAX6854–MAX6869 nanopower µP supervisory family, engineered specifically for battery-critical medical and portable electronics where ultra-low ICC and guaranteed brownout response are mandatory.

FAQ

What is the exact reset threshold voltage of the MAX6861UK20+T?

The MAX6861UK20+T has a factory-trimmed reset threshold of 2.0V with ±2.5% tolerance over -40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) where suffix "20" corresponds to VTH = 2.0V, and Electrical Characteristics specify VTH = VTH ±2.5% under all operating conditions. The MAX6861UK20+T maintains this accuracy without external calibration.

Does the MAX6861UK20+T include a watchdog timer function?

No, the MAX6861UK20+T does not include a watchdog timer. Per the Selector Guide and Pin Description, MAX6861/MAX6862/MAX6863 lack WDI pin and watchdog circuitry - only MAX6864–MAX6869 variants feature watchdog functionality. The MAX6861UK20+T provides voltage monitoring, manual reset, and pin-selectable reset timeout only.

How is the reset timeout period selected on the MAX6861UK20+T?

The reset timeout on the MAX6861UK20+T is selected via the CT pin: connect CT to GND for 10ms (min) timeout (D1 option), or connect CT to VCC for 150ms (min) timeout (D3 option). This is explicitly defined in Table 1 and the MAX6861/MAX6862/MAX6863 Pin Description section. The MAX6861UK20+T does not support other timeout values.

What is the minimum VCC voltage at which MAX6861UK20+T guarantees valid RESET output?

The MAX6861UK20+T guarantees valid RESET output down to VCC = 1.1V, as stated in the Features list ("Guaranteed Reset Valid to VCC = +1.1V") and confirmed in Electrical Characteristics (VCC = 1.1V minimum for RESET specification). Below 1.1V, RESET behavior is not characterized - the MAX6861UK20+T ensures deterministic reset assertion through deep brownout.

Is the MAX6861UK20+T pin-compatible with other supervisory ICs?

Yes, the MAX6861UK20+T is pin-compatible with TPS3836/TPS3837/TPS3838 devices per the Features section, sharing identical 5-pin SOT23 pinout (CT = IN, GND, MR, RESET, VCC). However, functional differences exist: TPS3836 lacks CT selectability and has fixed timeout, so direct substitution requires validation of timeout requirements. The MAX6861UK20+T retains full pin alignment.