Analog Devices Inc./Maxim Integrated MAX6863UK28+T

Overview

The MAX6863UK28+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring pin-selectable 10ms/150ms (min) reset timeout, active-low open-drain reset output, manual reset input (MR), and factory-trimmed 2.800V reset threshold. It monitors VCC down to 1.1V, draws only 170nA typical supply current, and is designed for reliable reset assertion during power-up, brownout, and software fault conditions in ultra-low-power systems.

For engineers reviewing the MAX6863UK28+T datasheet, MAX6863UK28+T pinout, MAX6863UK28+T application, or MAX6863UK28+T equivalent, this device is selected for battery-powered medical sensors, portable diagnostics, and energy-harvesting edge nodes where guaranteed reset validity at low VCC, immunity to short transients, and minimal quiescent current are critical design requirements.

Technical Context

The MAX6863UK28+T integrates a precision voltage monitor with ±2.5% threshold accuracy over temperature, a CT-controlled dual-reset-timeout generator (10ms or 150ms min), and a robust MR input with 10kΩ internal pullup and 250ns MR-to-reset delay. Its open-drain RESET output supports level-shifting up to 5.5V and remains valid down to VCC = 1.1V.

Unlike watchdog-equipped variants (e.g., MAX6864–MAX6869), the MAX6863UK28+T omits WDI functionality and instead provides CT pin selectability - enabling dynamic timeout selection without firmware changes. It operates across –40°C to +85°C and requires no external components beyond a 0.1µF VCC bypass capacitor.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5 (lead-free, +T suffix), 2.9mm × 1.6mm × 1.1mm body, gull-wing leads.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6863UK28+T, MAX6861UK28+T offers identical monitoring but lacks open-drain flexibility, while TPS3836K28DBVR trades timeout configurability for TI's long-term supply assurance - making MAX6863UK28+T optimal for designs requiring both voltage-level independence and field-adjustable timing.

Availability

MAX6863UK28+T is available at Aetrix Electronics and suitable for glucose monitors, patient loggers, industrial wireless sensors, and energy-harvesting IoT nodes requiring stable component supply with guaranteed long-term availability and lead-free compliance.

Supply support for MAX6863UK28+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 supervisory functions targeting battery-constrained and safety-critical embedded systems - emphasizing ultra-low ICC, guaranteed low-VCC operation, and minimal external component count.

FAQ

What is the exact reset threshold voltage of the MAX6863UK28+T?

The MAX6863UK28+T has a factory-trimmed reset threshold voltage of 2.800V, with ±2.5% tolerance over the full –40°C to +85°C temperature range. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "28" corresponds to 2.800V nominal. The MAX6863UK28+T maintains this accuracy without calibration or external components.

Does the MAX6863UK28+T include a watchdog timer function?

No, the MAX6863UK28+T does not include a watchdog timer. It belongs to the MAX6861/MAX6862/MAX6863 subgroup, which features pin-selectable reset timeout (via CT pin) and manual reset (MR), but omits WDI functionality. Watchdog capability is present only in MAX6864–MAX6869 variants - the MAX6863UK28+T is optimized for simplicity and lowest possible ICC in non-watchdog applications.

How does the CT pin on the MAX6863UK28+T configure reset timeout?

The CT pin on the MAX6863UK28+T selects between two minimum reset timeout periods: connect CT to GND for 10ms (min), or to VCC for 150ms (min). These values are specified in Table 1 of the datasheet, with typical values of 15ms and 225ms respectively. The timeout is latched at reset assertion and remains active until the next reset event - enabling hardware-based timing selection without firmware involvement.

What is the maximum sink current capability of the MAX6863UK28+T RESET output?

The MAX6863UK28+T RESET output is open-drain and has no active pull-down driver - its sink capability depends entirely on the external pullup resistor and load. However, the datasheet specifies VOL ≤ 0.3V at ISINK = 1.2mA (for VCC ≥ 2.38V), confirming it can reliably drive standard CMOS inputs. For robust operation, a 10kΩ pullup to 3.3V yields ~330µA sink current - well within safe limits for most µP reset inputs.

Is the MAX6863UK28+T pin-compatible with Texas Instruments TPS3836 devices?

Yes, the MAX6863UK28+T is pin-compatible with the TPS3836/TPS3837/TPS3838 series per the datasheet's Feature section, which explicitly states "Pin Compatible to the TPS3836/TPS3837/TPS3838 (MAX6861/MAX6862/MAX6863)". Both use identical 5-pin SOT23-5 footprints and share compatible pin assignments (CT/MR/GND/RESET/VCC), enabling direct replacement where open-drain output and CT-based timeout selection are required.