Analog Devices Inc./Maxim Integrated MAX6866UK23D3S+T

Overview

MAX6866UK23D3S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 2.313V reset threshold (±2.5%), 150ms minimum reset timeout, manual reset input (MR), and watchdog timer with 3.3s typical timeout. It ensures reliable power-on reset and brownout protection in battery-powered medical and portable electronics.

For engineers reviewing the MAX6866UK23D3S+T datasheet, MAX6866UK23D3S+T pinout, MAX6866UK23D3S+T application, or MAX6866UK23D3S+T equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), open-drain active-low RESET output, and compatibility with noisy low-voltage systems requiring minimal quiescent current.

Technical Context

The MAX6866UK23D3S+T integrates voltage monitoring, a manual reset input (MR), and a watchdog timer that monitors WDI activity to detect firmware hangs. Its reset assertion logic triggers on VCC falling below 2.313V, MR low pulse ≥1µs, or WDI inactivity exceeding 3.3s (typ), with hysteresis of 0.5%VTH ensuring noise immunity.

After reset initiation, the device holds RESET asserted for a fixed 150ms (min) timeout - determined by the D3 suffix - independent of VCC recovery slope. The open-drain RESET output requires an external pullup and sinks ≤50µA at VOL ≤0.3V, enabling level-shifting across logic domains while maintaining valid reset signaling down to VCC = 1.1V.

Key Specifications

Pinout & Package

MAX6866UK23D3S+T is housed in a lead-free 5-pin SOT23-5 package (JEDEC MO-178AA), with 1.3mm height and 2.9mm × 1.6mm footprint. Pin 1 is marked with a dot; pin numbering follows standard SOT23 top-view orientation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK23D3S+T and TPS3838K23DBVR, MAX6866UK23D3S+T uniquely delivers open-drain RESET for multi-rail compatibility while maintaining 170nA ICC and integrated watchdog - essential for long-life, safety-critical portable medical devices.

Availability

MAX6866UK23D3S+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, MP3 players, and smart pagers requiring stable component supply with guaranteed long-term availability and lead-free compliance.

Supply support for MAX6866UK23D3S+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 portable applications.

The MAX6854–MAX6869 family was engineered specifically for ultra-low-power microprocessor supervision in battery-constrained systems, emphasizing nanoscale ICC, wide VCC range, and robust glitch immunity.

FAQ

What is the exact reset threshold voltage of MAX6866UK23D3S+T?

The MAX6866UK23D3S+T has a factory-trimmed reset threshold voltage of 2.313V, with ±2.5% tolerance over temperature (-40°C to +85°C). This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "23" corresponds to 2.313V nominal. The device guarantees reset assertion when VCC falls below this threshold and maintains validity down to VCC = 1.1V.

Does MAX6866UK23D3S+T include a watchdog timer, and what is its timeout?

Yes, MAX6866UK23D3S+T includes a watchdog timer with a typical timeout of 3.3 seconds, indicated by the "S" suffix in the part number. The watchdog monitors the WDI pin and triggers reset if no edge (rising or falling) occurs within this period. The timer clears on any WDI transition, MR assertion, or RESET assertion - ensuring responsive fault recovery without requiring software polling.

What does the "D3" in MAX6866UK23D3S+T signify?

The "D3" suffix in MAX6866UK23D3S+T specifies a minimum reset timeout period of 150ms, per Table 4 (Reset Timeout Periods) in the datasheet. This fixed timeout begins after VCC rises above the 2.313V threshold or MR deasserts, ensuring the microprocessor has sufficient time to stabilize before release. It is not user-adjustable and applies regardless of VCC ramp rate.

Is MAX6866UK23D3S+T compatible with 1.8V microcontrollers?

Yes, MAX6866UK23D3S+T operates from VCC = 1.2V to 5.5V and is fully compatible with 1.8V systems. Its 2.313V reset threshold is appropriate for monitoring 2.5V rails, but it can supervise 1.8V supplies using external resistor dividers. The open-drain RESET output can be pulled up to the µP's I/O voltage (e.g., 1.8V), and VOL ≤0.3V ensures solid low-level signaling into 1.8V logic inputs.

What package type and RoHS status does MAX6866UK23D3S+T use?

MAX6866UK23D3S+T uses a lead-free 5-pin SOT23-5 package (JEDEC MO-178AA), as confirmed by the "+T" suffix denoting RoHS-compliant packaging. The package measures 2.9mm × 1.6mm with 1.3mm max height and features gull-wing leads suitable for standard reflow soldering. Pin 1 is marked with a dot, and pinout matches the MAX6864–MAX6866 series configuration.