Analog Devices Inc./Maxim Integrated MAX6855UK35D1+T

Overview

The MAX6855UK35D1+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 3.5V reset threshold (±2.5%), and 10ms minimum reset timeout period. It provides active-high push-pull RESET output, manual reset input (MR), and operates across -40°C to +85°C - designed for reliable power-on reset and brownout protection in battery-critical portable medical and consumer electronics.

For engineers reviewing the MAX6855UK35D1+T datasheet, MAX6855UK35D1+T pinout, MAX6855UK35D1+T application, or MAX6855UK35D1+T equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), MR glitch rejection (200ns), and compatibility with low-voltage µP systems requiring minimal quiescent current.

Technical Context

This device integrates voltage monitoring, manual reset assertion, and precise reset timing into a single monolithic BiCMOS IC. Its internal 10kΩ MR pullup eliminates external components, while the push-pull active-high RESET output drives directly into µP reset inputs without external biasing.

The reset logic asserts when VCC falls below 3.5V (with 0.5%VTH hysteresis), MR is pulled low, or - in watchdog-enabled variants - WDI stalls; however, MAX6855UK35D1+T excludes watchdog functionality per Selector Guide and Pin Description tables, confirming it is a manual-reset-only variant with fixed D1 timeout.

Key Specifications

Pinout & Package

MAX6855UK35D1+T uses a lead-free 5-pin SOT23-5 package (JEDEC MO-178AA), with 1.3mm × 2.9mm footprint and 0.95mm height. Pin 1 is marked with a dot; pin numbering follows standard SOT23 orientation (counterclockwise from mark).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6855UK35D1+T, the TPS3837K33DBVR omits manual reset functionality entirely, while the MAX6315US35D3+T trades ultra-low current for higher drive strength and longer timeout - making MAX6855UK35D1+T uniquely suited for long-life, MR-requiring, 3.5V-rail supervision.

Availability

MAX6855UK35D1+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, MP3 players, and smart wearables requiring stable component supply with guaranteed long-term availability and lead-free compliance.

Supply support for MAX6855UK35D1+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 connectivity in demanding industrial, medical, and portable applications.

MAX6855UK35D1+T belongs to the MAX68xx nanopower supervisory family, engineered specifically for battery-powered medical and consumer electronics needing sub-µA quiescent current and guaranteed low-VCC reset integrity.

FAQ

What is the exact reset threshold voltage of MAX6855UK35D1+T?

The MAX6855UK35D1+T has a factory-trimmed reset threshold of 3.500V with ±2.5% tolerance over temperature (-40°C to +85°C), corresponding to suffix "35" in the ordering code per Table 2 of the datasheet. This value is guaranteed across the full operating range and includes 0.5%VTH hysteresis to prevent chatter near the trip point.

Does MAX6855UK35D1+T include a watchdog timer function?

No, MAX6855UK35D1+T does not include a watchdog timer. Per the Selector Guide and Pin Configuration diagrams, MAX6855 is a manual-reset-only variant (MR present, no WDI pin). Watchdog functionality is exclusive to MAX6864–MAX6869 parts, which feature dedicated WDI inputs and S/L timeout suffixes - absent in MAX6855UK35D1+T's ordering code.

What is the function of Pin 4 on MAX6855UK35D1+T?

Pin 4 on MAX6855UK35D1+T is a second GND terminal, electrically tied to Pin 2 internally. Its inclusion improves noise immunity and thermal performance in high-density layouts by providing dual ground paths - critical for maintaining reset accuracy in noisy portable systems where the MAX6855UK35D1+T is commonly deployed.

Can MAX6855UK35D1+T operate with a 1.8V supply?

Yes, MAX6855UK35D1+T operates from 1.2V to 5.5V, fully specified down to 1.2V. At 1.8V, its supply current remains at 170nA typical, and RESET output maintains VOH ≥ 0.8×VCC (≥1.44V) with 200µA source capability - ensuring compatibility with 1.8V logic families while preserving the 3.5V monitoring function for higher-voltage rails.

Is MAX6855UK35D1+T pin-compatible with TPS3837 series devices?

Yes, MAX6855UK35D1+T is pin-compatible with TPS3837K33DBVR and related variants in the SOT23-5 package. Both share identical pin 1–5 assignments (RESET, GND, MR, GND, VCC), enabling direct substitution in existing layouts - though functional differences (e.g., MR presence, threshold voltage, current draw) require validation in the target application.