Analog Devices Inc./Maxim Integrated MAX6855UK42D4+T

Overview

The MAX6855UK42D4+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 4.200V reset threshold (±2.5%), and 1200ms minimum reset timeout period. It provides active-low push-pull reset output, manual reset input (MR), and operates across -40°C to +85°C - designed for reliable power-up/brownout monitoring in battery-powered medical and portable electronics.

For engineers reviewing the MAX6855UK42D4+T datasheet, MAX6855UK42D4+T pinout, MAX6855UK42D4+T application, or MAX6855UK42D4+T equivalent, this page delivers verified functional identity, validated pin roles, confirmed timing parameters, and real-world design context for low-power µP reset supervision in glucose monitors, patient monitors, and handheld devices.

Technical Context

This device integrates voltage monitoring, manual reset assertion, and reset timeout generation - but excludes watchdog timer functionality (distinguishing it from MAX6864–MAX6869 variants). Its internal reset generator asserts RESET when VCC falls below 4.200V or MR is pulled low, holding the signal active for ≥1200ms after VCC rises above threshold and MR deasserts.

The push-pull active-low RESET output is referenced to VCC and guarantees valid operation down to VCC = +1.1V, with VOL ≤ 0.3V at ISINK = 1.2mA (VCC ≥ 2.38V) and VOH ≥ 0.8×VCC at ISOURCE = 500µA. Immunity to short VCC transients (<40µs at 100mV overdrive) ensures robustness in noisy supply environments.

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 TPS3837K33DBVR and MAX6361KA29D3+T, the MAX6855UK42D4+T uniquely combines 4.200V precision threshold, MR support, 170nA ICC, and 1200ms timeout in one SOT23-5 device - making it irreplaceable for Li-ion battery-supervised medical wearables requiring guaranteed reset hold time and manual recovery.

Availability

MAX6855UK42D4+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, and handheld PDAs requiring stable component supply, long-term lifecycle support, and lead-free compliance.

Supply support for MAX6855UK42D4+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, sensing, and interface applications - with emphasis on reliability and low-power innovation.

The MAX6854–MAX6869 family was engineered specifically for nanopower microprocessor supervision in battery-critical medical and portable electronics, delivering factory-trimmed accuracy and minimal external component count.

FAQ

What is the exact reset threshold voltage of the MAX6855UK42D4+T?

The MAX6855UK42D4+T has a factory-trimmed reset threshold voltage of 4.200V, with tolerance of ±2.5% 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 "42" corresponds to 4.200V nominal. The MAX6855UK42D4+T maintains this accuracy without external calibration components.

Does the MAX6855UK42D4+T include a watchdog timer function?

No, the MAX6855UK42D4+T does not include a watchdog timer. Per the Selector Guide and Pin Configurations section, only MAX6864–MAX6869 variants feature WDI input and watchdog timeout capability. The MAX6855UK42D4+T is a dedicated voltage supervisor with manual reset (MR) and fixed reset timeout - confirmed by absence of WDI pin and watchdog-related electrical characteristics in its specification table.

What is the reset timeout period for the MAX6855UK42D4+T, and how is it set?

The MAX6855UK42D4+T has a fixed 1200ms minimum reset timeout period, indicated by the "D4" suffix in its part number. This value is factory-programmed and non-adjustable - unlike MAX6861–MAX6863 variants with CT-selectable timeouts. The timeout begins after VCC rises above 4.200V and MR is deasserted, and is guaranteed across temperature and voltage per Table 4 (Reset Timeout Periods).

What type of reset output does the MAX6855UK42D4+T provide?

The MAX6855UK42D4+T provides an active-low push-pull reset output on Pin 1. As documented in the MAX6854/MAX6855/MAX6856 Pin Description, this configuration eliminates the need for an external pullup resistor and directly drives standard CMOS reset inputs. It differs from open-drain or active-high variants in the same family (e.g., MAX6856 or MAX6855), and is electrically verified with VOL ≤ 0.3V at 1.2mA sink current.

Is the MAX6855UK42D4+T compatible with other SOT23-5 supervisory ICs?

The MAX6855UK42D4+T shares the same 5-pin SOT23-5 package and pinout as TPS3836/TPS3837/TPS3838 devices (per datasheet Feature list), enabling drop-in replacement in many layouts. However, direct substitution requires verification of threshold voltage (4.200V vs. TPS3837's 3.3V), reset timeout (1200ms vs. 200ms), and MR functionality - as electrical behavior and timing differ significantly despite mechanical compatibility.