Analog Devices Inc./Maxim Integrated MAX6855UK19D6+T

Overview

The MAX6855UK19D6+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, providing voltage monitoring, manual reset input (MR), and fixed 1200ms reset timeout. It asserts an active-high push-pull RESET output when VCC drops below 1.900V (±2.5%), MR is pulled low, or during power-up/brownout - guaranteed valid down to VCC = +1.1V. Used in battery-powered glucose monitors and portable medical devices requiring ultra-low quiescent current.

For engineers reviewing the MAX6855UK19D6+T datasheet, MAX6855UK19D6+T pinout, MAX6855UK19D6+T application, or MAX6855UK19D6+T equivalent, key selection criteria include its 170nA typical supply current, factory-trimmed 1.900V reset threshold, 1200ms minimum reset timeout, active-high push-pull output configuration, and immunity to short VCC transients - all critical for low-power embedded system reliability.

Technical Context

This device implements a precision bandgap-based voltage monitor with 2.5% threshold tolerance and 0.5% hysteresis, coupled to a digital timeout counter that holds RESET asserted for ≥600ms after VCC exceeds VTH and MR deasserts. The internal 10kΩ MR pullup enables direct interface with momentary switches or CMOS logic without external components.

No watchdog timer or CT pin functionality is present - the MAX6855UK19D6+T is a dedicated manual-reset supervisory IC with fixed timing and active-high push-pull output, distinct from MAX6864–MAX6869 (watchdog) or MAX6861–MAX6863 (pin-selectable timeout) variants.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, surface-mount, lead-free (RoHS-compliant).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3837K33DBVR and MAX6326UR29+T, the MAX6855UK19D6+T offers the lowest quiescent current (170nA vs. >1µA), precise 1.900V threshold for 1.8V/1.9V systems, and active-high push-pull output eliminating external biasing - making it optimal for ultra-low-power medical and portable electronics.

Availability

MAX6855UK19D6+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitoring devices, and MP3 players requiring stable component supply across extended production lifecycles and global regulatory compliance.

Supply support for MAX6855UK19D6+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 communications applications.

The MAX6854–MAX6869 family delivers nanopower supervisory functions for battery-critical systems - engineered specifically for long-life portable medical equipment and handheld consumer electronics requiring sub-µA quiescent current and guaranteed reset behavior down to 1.1V.

FAQ

What is the exact reset threshold voltage of the MAX6855UK19D6+T?

The MAX6855UK19D6+T has a factory-trimmed reset threshold of 1.900V with ±2.5% tolerance over -40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "19" corresponds to 1.900V nominal. The device guarantees reset assertion when VCC falls below this threshold and remains asserted until VCC exceeds 1.900V and the 1200ms timeout expires.

Does the MAX6855UK19D6+T include a watchdog timer function?

No, the MAX6855UK19D6+T does not include a watchdog timer. It belongs to the MAX6854/MAX6855/MAX6856 subgroup, which provides only voltage monitoring and manual reset (MR) functionality. Watchdog capability is exclusive to MAX6864–MAX6869 variants (e.g., MAX6864UK19D6S+T), identifiable by the "S" or "L" suffix in the ordering code.

What is the reset output configuration of the MAX6855UK19D6+T?

The MAX6855UK19D6+T features an active-high push-pull RESET output (Pin 1), as confirmed in the Pin Description table and Selector Guide. When reset is asserted, RESET drives high to VCC; when deasserted, it drives low. This eliminates the need for an external pullup resistor and provides direct compatibility with µP reset inputs expecting active-high logic.

What is the minimum reset timeout period for the MAX6855UK19D6+T?

According to Table 4 (Reset Timeout Periods), the "D6" suffix in MAX6855UK19D6+T specifies a minimum reset timeout period of 600ms, with typical 900ms and maximum 1200ms values. The device guarantees RESET remains asserted for at least 600ms after VCC rises above 1.900V and MR is deasserted - sufficient for full µP initialization in low-power embedded systems.

Is the MAX6855UK19D6+T compatible with 1.2V supply rails?

Yes, the MAX6855UK19D6+T operates across VCC = 1.2V to 5.5V and guarantees valid reset behavior down to VCC = +1.1V. At 1.2V supply, its 170nA typical supply current and 1.900V threshold ensure robust brownout detection - though note that 1.900V exceeds 1.2V, so reset will assert continuously until VCC rises above threshold, as intended for undervoltage lockout.