Analog Devices Inc./Maxim Integrated MAX6865UK16D4S+T

Overview

The MAX6865UK16D4S+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, 1200ms minimum reset timeout, manual reset input (MR), and watchdog timer with 3.3s typical timeout. It monitors VCC in battery-powered systems to assert active-low push-pull RESET during brownout, power-up, or software hang.

For engineers reviewing the MAX6865UK16D4S+T datasheet, MAX6865UK16D4S+T pinout, MAX6865UK16D4S+T application, or MAX6865UK16D4S+T equivalent, this device serves as a low-power, single-chip solution for reliable µP reset control and watchdog supervision in space-constrained portable electronics where supply current below 200nA and guaranteed reset validity down to VCC = +1.1V are critical.

Technical Context

The MAX6865UK16D4S+T integrates voltage monitoring, a manual reset input (MR), and a watchdog timer that triggers reset if WDI remains static beyond 3.3s (typ). Its internal reset timeout generator enforces a fixed 1200ms minimum assertion period after VCC recovery or MR release.

It uses BiCMOS process technology (2848 transistors) and features immunity to short VCC transients (<40µs at 100mV overdrive), guaranteed RESET validity down to VCC = +1.1V, and CMOS-compatible MR/WDI inputs with 10kΩ internal pullup on MR and 20nA max input leakage.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount, footprint compatible with industry-standard 5-pin SOT23 layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6865UK16D4S+T, MAX6864UK16D4S+T offers identical supervision specs but no active-high RESET variant, while TPS3836K33DBVR trades nanopower operation and watchdog capability for lower unit cost in non-critical reset-only designs.

Availability

MAX6865UK16D4S+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, MP3 players, and PDAs requiring stable component supply with long-term lifecycle support and lead-free compliance.

Supply support for MAX6865UK16D4S+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 high-performance analog and mixed-signal ICs for power, interface, sensing, and timing applications.

The MAX6865UK16D4S+T belongs to the MAX6854–MAX6869 nanopower µP supervisory family, engineered specifically for ultra-low-power portable and medical electronics where sub-200nA supply current and integrated watchdog supervision are mandatory.

FAQ

What is the reset threshold voltage of the MAX6865UK16D4S+T?

The MAX6865UK16D4S+T has a factory-trimmed reset threshold voltage of +1.575V, 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 "16" corresponds to 1.575V. The MAX6865UK16D4S+T maintains valid reset assertion down to VCC = +1.1V, ensuring reliable operation during deep brownout conditions.

Does the MAX6865UK16D4S+T include a watchdog timer, and what is its timeout?

Yes, the MAX6865UK16D4S+T includes a watchdog timer with a typical timeout of 3.3s, denoted by the "S" suffix in the part number. As specified in Table 3 (Watchdog Timeout), the "S" option provides a minimum of 1.5s and maximum of 7.75s timeout. The timer clears on any rising or falling edge at the WDI pin and triggers reset if no transition occurs within the timeout window - a key feature distinguishing MAX6865UK16D4S+T from basic reset-only supervisors.

What is the reset timeout period for the MAX6865UK16D4S+T?

The MAX6865UK16D4S+T has a fixed minimum reset timeout period of 1200ms, indicated by the "D4" suffix. Per Table 4 (Reset Timeout Periods), D4 corresponds to 1200ms (min), 1800ms (typ), and 2400ms (max). This timeout begins after VCC rises above the 1.575V threshold or after MR is released, ensuring the microprocessor completes power-up initialization before reset deassertion.

What type of RESET output does the MAX6865UK16D4S+T provide?

The MAX6865UK16D4S+T provides an active-low push-pull RESET output, as confirmed by its pin description (Pin 1 = RESET, active-low push-pull) and Selector Guide entry. This eliminates the need for an external pullup resistor and allows direct connection to standard µP reset inputs. Unlike open-drain variants, it actively drives both high and low states, improving noise immunity and reducing external component count.

Is the MAX6865UK16D4S+T pin-compatible with other devices in the MAX68xx family?

The MAX6865UK16D4S+T is pin-compatible with other 5-pin SOT23 members of the MAX6854–MAX6869 family, including MAX6864/MAX6866/MAX6867, sharing identical pin 1 (RESET), pin 2 (GND), pin 3 (MR), pin 4 (WDI), and pin 5 (VCC) assignments. However, it is not pin-compatible with MAX6861–MAX6863 (which use pin 1 for CT) or MAX6858/MAX6860 (which repurpose pins 1 and 2 as I.C.). Always verify pin function per device variant.