Analog Devices Inc./Maxim Integrated MAX6855UK17D4+T

Overview

The MAX6855UK17D4+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 1.665V reset threshold (suffix "17"), and 1200ms minimum reset timeout (suffix "D4"). It provides active-high push-pull RESET output, manual reset input (MR), and operates across –40°C to +85°C. It ensures reliable power-on reset and brownout protection in battery-powered medical and portable electronics.

For engineers reviewing the MAX6855UK17D4+T datasheet, MAX6855UK17D4+T pinout, MAX6855UK17D4+T application, or MAX6855UK17D4+T equivalent, this page delivers verified electrical parameters, exact pin functions, real-world use cases in glucose monitors and patient monitors, and two confirmed alternative parts with documented functional and timing differences.

Technical Context

The MAX6855UK17D4+T integrates voltage monitoring, manual reset assertion, and reset timing logic - but no watchdog timer (absent WDI pin per Selector Guide and Pin Description). Its internal comparator continuously monitors VCC against a precision 1.665V threshold; when VCC falls below this level, the active-high push-pull RESET asserts high and remains asserted for ≥1200ms after VCC rises above threshold and MR deasserts.

It guarantees valid RESET operation down to VCC = +1.1V, features 250ns MR-to-reset delay, 1µs minimum MR pulse width, and 200ns MR glitch rejection. The MR input includes a 10kΩ internal pullup to VCC, enabling direct connection of a momentary switch to GND without external components.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5 (lead-free, +T suffix), 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 MAX6855UK17D4+T, MAX6854UK17D4+T offers identical threshold and timeout but different reset polarity and drive type - requiring schematic and layout review for pullup integration; TPS3837K33DBVR trades nanopower operation and adjustable threshold for TI's production scalability and automotive qualification, but lacks the 1.1V validity guarantee.

Availability

MAX6855UK17D4+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, and MP3 players requiring stable component supply, long-term lifecycle support, and lead-free compliance.

Supply support for MAX6855UK17D4+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 industrial, medical, and communications applications.

The MAX685x family delivers nanopower supervisory circuits optimized for battery-critical portable medical and consumer devices, emphasizing ultra-low ICC, guaranteed low-VCC reset validity, and minimal external component count.

FAQ

What is the reset threshold voltage of the MAX6855UK17D4+T?

The MAX6855UK17D4+T has a factory-trimmed reset threshold voltage of 1.665V, with ±2.5% tolerance over temperature. This value is encoded in the "17" suffix per the Threshold Suffix Guide (Table 2), and is validated across –40°C to +85°C. The MAX6855UK17D4+T asserts its active-high RESET output whenever VCC falls below this threshold, ensuring reliable brownout detection in 1.8V systems.

Does the MAX6855UK17D4+T include a watchdog timer?

No, the MAX6855UK17D4+T does not include a watchdog timer. Per the Selector Guide and Pin Configuration diagrams, MAX6855 variants lack the WDI (Watchdog Input) pin and associated internal circuitry. Only MAX6864–MAX6869 parts integrate watchdog functionality. The MAX6855UK17D4+T provides voltage monitoring, manual reset, and fixed reset timeout - making it suitable for applications where software-level watchdog supervision is handled externally.

What is the function of Pin 4 on the MAX6855UK17D4+T?

Pin 4 on the MAX6855UK17D4+T is a second GND terminal, electrically connected internally to Pin 2 (GND). This dual-GND configuration improves thermal dissipation and reduces ground impedance in high-noise environments. It must be connected to the same system ground plane as Pin 2 - not left floating - to maintain specified reset threshold accuracy and noise immunity per the Absolute Maximum Ratings and Typical Operating Characteristics.

How does the MR input behave on the MAX6855UK17D4+T?

The MR input on the MAX6855UK17D4+T is active-low with an internal 10kΩ pullup to VCC. Driving MR low for ≥1µs asserts the active-high RESET output for the full 1200ms timeout period, even after MR returns high. Glitch rejection filters pulses <200ns. If unused, MR may be left unconnected (relying on internal pullup) or tied to VCC. The MAX6855UK17D4+T datasheet confirms no external components are needed for basic MR functionality.

Is the MAX6855UK17D4+T compatible with 1.1V supply rails?

The MAX6855UK17D4+T guarantees valid RESET output operation down to VCC = +1.1V, meaning the active-high RESET signal remains well-defined (VOH ≥ 0.8×VCC, VOL ≤ 0.3V) even as supply voltage collapses. However, the device itself requires VCC ≥ 1.2V to function per Electrical Characteristics - so while RESET stays valid to 1.1V, the IC ceases supervision below 1.2V. This behavior is explicitly tested and guaranteed, unlike many supervisors that fail silently near VCC min.