Analog Devices Inc./Maxim Integrated MAX6866UK16D3S+T

Overview

The MAX6866UK16D3S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, a factory-trimmed 1.575V reset threshold (suffix '16'), 150ms minimum reset timeout (suffix 'D3'), and watchdog timer with 3.3s typical timeout (suffix 'S'). It monitors VCC, responds to manual reset (MR), and triggers reset on watchdog expiration - designed for battery-powered medical and portable electronics requiring guaranteed reset validity down to VCC = +1.1V.

For engineers reviewing the MAX6866UK16D3S+T datasheet, MAX6866UK16D3S+T pinout, MAX6866UK16D3S+T application, or MAX6866UK16D3S+T equivalent, key selection criteria include its open-drain active-low RESET output, watchdog input (WDI) timing compatibility, 1.575V threshold tolerance over temperature, and immunity to sub-40µs VCC transients - all critical for low-voltage, long-life embedded systems.

Technical Context

This device integrates three core functions: precision voltage monitoring with ±2.5% threshold accuracy, a manual reset input with 1µs minimum pulse width and 200ns glitch rejection, and a watchdog timer that clears on any WDI edge and expires after 3.3s (typ) if inactive. Its internal 10kΩ MR pullup and guaranteed reset assertion down to VCC = +1.1V enable robust brownout recovery without external components.

The MAX6866UK16D3S+T uses a BiCMOS process and implements a fixed-reset-timeout architecture (150ms min) with no external timing components. Its open-drain RESET output requires an external pullup and supports level-shifting across logic domains up to 5.5V, while its WDI input accepts CMOS-compatible signals with 150ns minimum pulse width detection.

Key Specifications

Pinout & Package

Package: 5-pin SOT23 (lead-free, +T suffix), footprint-compatible with industry-standard 5-lead SOT-23 packages. Thermal pad not present; standard reflow profile applies.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6866UK16D3S+T, MAX6864UK16D3S+T offers identical supervision timing but less interface flexibility, while TPS3836K33DBVR trades nanopower efficiency and watchdog capability for lower unit cost - making MAX6866UK16D3S+T optimal for battery-constrained, safety-aware applications requiring both precision reset and fail-safe watchdog coverage.

Availability

MAX6866UK16D3S+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign loggers, industrial wireless sensor nodes, and smart hearing aids requiring stable component supply across extended production lifecycles.

Supply support for MAX6866UK16D3S+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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, medical, and communications applications.

The MAX6854–MAX6869 family was designed specifically for ultra-low-power microprocessor supervision in portable and battery-operated medical devices, emphasizing nanoscale current consumption, precise voltage thresholds, and integrated watchdog reliability.

FAQ

What is the exact reset threshold voltage of the MAX6866UK16D3S+T?

The MAX6866UK16D3S+T has a factory-trimmed reset threshold voltage of +1.575V, with ±2.5% tolerance over the full -40°C to +85°C operating temperature range. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix '16' corresponds to 1.575V nominal. The MAX6866UK16D3S+T maintains this accuracy without external calibration.

Does the MAX6866UK16D3S+T support watchdog timer functionality, and what is its timeout period?

Yes, the MAX6866UK16D3S+T includes a watchdog timer with a typical timeout period of 3.3 seconds, indicated by the 'S' suffix in the part number. The watchdog clears on any rising or falling edge at the WDI pin and expires only if WDI remains static beyond this period. The MAX6866UK16D3S+T does not support the longer 209s timeout option ('L' suffix).

What type of RESET output does the MAX6866UK16D3S+T provide, and how should it be interfaced?

The MAX6866UK16D3S+T provides an open-drain active-low RESET output (Pin 1). It requires an external pullup resistor to the target logic voltage (e.g., 1.8V, 3.3V, or 5V) and can interface across voltage domains. The MAX6866UK16D3S+T guarantees sinking capability down to VCC = +1.1V, ensuring reliable reset assertion even during deep brownout conditions.

What is the minimum reset timeout period for the MAX6866UK16D3S+T, and how is it set?

The MAX6866UK16D3S+T has a fixed minimum reset timeout period of 150ms, denoted by the 'D3' suffix. This value is factory-programmed and cannot be adjusted externally. The MAX6866UK16D3S+T asserts RESET for at least 150ms after VCC rises above 1.575V or MR is deasserted, ensuring sufficient hold time for microprocessor power stabilization.

Is the MAX6866UK16D3S+T compatible with other SOT23-5 supervisory ICs, and what are the key pin differences?

The MAX6866UK16D3S+T uses a standard 5-pin SOT23 footprint and shares pin 1 (RESET), pin 2 (GND), pin 3 (MR), pin 4 (WDI), and pin 5 (VCC) with other MAX686x variants. It is not pin-compatible with MAX685x or MAX6861–MAX6863 families due to differing pin functions (e.g., CT or I.C. pins). The MAX6866UK16D3S+T requires verification against schematic symbols before drop-in replacement.