Analog Devices Inc./Maxim Integrated MAX6855UK26D6+T

Overview

The MAX6855UK26D6+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 600ms–1200ms reset timeout. It asserts an active-high push-pull RESET output when VCC drops below its factory-trimmed 2.625V threshold, during MR assertion, or after power-up/brownout - ensuring reliable µP initialization in battery-powered medical and portable systems.

For engineers reviewing the MAX6855UK26D6+T datasheet, MAX6855UK26D6+T pinout, MAX6855UK26D6+T application, or MAX6855UK26D6+T equivalent, this device delivers ultra-low 170nA typical supply current, guaranteed RESET validity down to VCC = +1.1V, immunity to short VCC transients, and no external components required - critical for low-power, space-constrained designs.

Technical Context

This supervisory IC integrates a precision voltage detector with ±2.5% threshold accuracy over -40°C to +85°C, a monolithic reset timeout generator with 600ms (min) / 900ms (typ) / 1200ms (max) delay, and a CMOS-compatible active-high push-pull RESET driver capable of sourcing ≥0.8×VCC at 500µA. The MR input features 10kΩ internal pullup, 1µs minimum pulse width, and 200ns glitch rejection.

Unlike watchdog-equipped variants (e.g., MAX6864–MAX6869), the MAX6855UK26D6+T omits WDI functionality and CT select input, simplifying design for applications requiring only voltage monitoring and manual reset. Its push-pull active-high output eliminates need for external pullup resistors and ensures deterministic logic levels across full VCC range (1.2V–5.5V).

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5 (lead-free, +T suffix), 2.9mm × 1.6mm footprint, 1.1mm height - compatible with standard pick-and-place and reflow processes.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3837K26DBVR and MAX6326UT26D3+T, the MAX6855UK26D6+T uniquely combines ultra-low 170nA supply current, 600–1200ms configurable timeout, and active-high push-pull output - enabling longer battery life, simpler layout, and compatibility with modern low-voltage µPs requiring high-true reset signaling.

Availability

MAX6855UK26D6+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, MP3 players, and smart pagers requiring stable component supply, long-term lifecycle support, and lead-free compliance.

Supply support for MAX6855UK26D6+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 portable applications.

The MAX6854–MAX6869 family targets ultra-low-power microprocessor supervision in battery-critical systems, emphasizing nanopower operation, small footprint, and robust reset timing without external components.

FAQ

What is the exact reset threshold voltage of the MAX6855UK26D6+T?

The MAX6855UK26D6+T has a factory-trimmed reset threshold of 2.625V, with ±2.5% tolerance over the full -40°C to +85°C operating temperature range. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "26" corresponds to 2.625V nominal. The threshold remains stable across VCC from 1.2V to 5.5V and is guaranteed valid down to VCC = +1.1V.

Does the MAX6855UK26D6+T include a watchdog timer function?

No, the MAX6855UK26D6+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 the MAX6864–MAX6869 variants, identifiable by "S" or "L" suffixes in the ordering code. The MAX6855UK26D6+T pinout lacks WDI and uses Pins 1 and 4 exclusively for RESET and GND.

What is the reset timeout period for the MAX6855UK26D6+T, and how is it set?

The MAX6855UK26D6+T has a fixed reset timeout period of 600ms (minimum), 900ms (typical), and 1200ms (maximum), as defined by the "D6" suffix in its part number. This timeout is factory-programmed and non-adjustable - unlike the MAX6861–MAX6863 series, which use the CT pin for selection. The timeout begins when VCC rises above the 2.625V threshold and MR is deasserted, ensuring sufficient hold time for µP initialization.

What type of RESET output does the MAX6855UK26D6+T provide, and how is it interfaced?

The MAX6855UK26D6+T provides an active-high push-pull RESET output on Pin 1. It drives high (≥0.8×VCC) when deasserted and low (<0.3V) when asserted, eliminating the need for external pullup resistors. This output directly interfaces with µPs requiring active-high reset inputs, such as many ARM Cortex-M and RISC-V devices. No level-shifting or additional passive components are required for standard 1.8V–3.3V logic families.

Is the MAX6855UK26D6+T pin-compatible with other devices in the MAX68xx family?

The MAX6855UK26D6+T shares the same 5-pin SOT23-5 package and Pin 1–5 assignment (RESET, GND, MR, GND, VCC) with MAX6854, MAX6856, MAX6861–MAX6863, and MAX6864–MAX6866 variants. However, functional pin equivalence is limited: MAX6855's Pin 1 is active-high push-pull RESET, whereas MAX6854 uses active-low push-pull and MAX6856 uses active-low open-drain. Swapping requires verification of reset polarity and drive strength compatibility.