Analog Devices Inc./Maxim Integrated MAX6855UK44D6+T

Overview

The MAX6855UK44D6+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 4.266V (min) / 4.375V (typ) reset threshold, and 600ms–1200ms minimum reset timeout period. It provides active-high push-pull RESET output, manual reset input (MR), and operates across –40°C to +85°C for battery-powered medical and portable electronics.

For engineers reviewing the MAX6855UK44D6+T datasheet, MAX6855UK44D6+T pinout, MAX6855UK44D6+T application, or MAX6855UK44D6+T equivalent, this device serves as a precision voltage monitor with deterministic reset timing, MR-initiated recovery, and guaranteed reset validity down to VCC = +1.1V - critical for low-voltage brownout resilience in glucose monitors and wearables.

Technical Context

The MAX6855UK44D6+T implements a precision bandgap-based voltage comparator with 2.5% threshold tolerance and 0.5% hysteresis to reject noise-induced false resets. Its internal timer ensures reset assertion persists for ≥600ms after VCC exceeds the 4.375V threshold and MR deasserts, with <250ns MR-to-reset delay and 1µs minimum MR pulse width.

This variant belongs to the MAX6854–MAX6869 family configured for manual reset only (no watchdog or CT select), with push-pull active-high RESET output referenced to VCC. It guarantees valid reset signaling at VCC as low as +1.1V and exhibits immunity to ≤40µs VCC transients when overdriven by 100mV.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, surface-mount, lead-free (RoHS-compliant), 2.9mm × 1.6mm footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3837K33DBVR and ADM6807-43ARTZ-R7, the MAX6855UK44D6+T delivers 14× lower supply current, integrated MR support, and tighter threshold accuracy - making it optimal for next-generation portable medical devices where battery longevity and deterministic reset control are non-negotiable.

Availability

MAX6855UK44D6+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign loggers, wireless hearing aids, and industrial handheld scanners requiring stable component supply with long-term lifecycle assurance.

Supply support for MAX6855UK44D6+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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, medical, and communications markets.

The MAX6854–MAX6869 product line was designed specifically for ultra-low-power microprocessor supervision in battery-critical applications, emphasizing nanoscale current consumption, precision voltage thresholds, and robust transient immunity.

FAQ

What is the exact reset threshold voltage of the MAX6855UK44D6+T?

The MAX6855UK44D6+T has a factory-trimmed reset threshold of 4.266V (minimum), 4.375V (typical), and 4.484V (maximum) at TA = +25°C, with ±2.5% tolerance over –40°C to +85°C. This corresponds to the "44" suffix in the part number per Maxim's Threshold Suffix Guide (Table 2). The MAX6855UK44D6+T guarantees valid reset assertion down to VCC = +1.1V regardless of threshold drift.

Does the MAX6855UK44D6+T include a watchdog timer function?

No, the MAX6855UK44D6+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., MAX6864UKxxDxxS/T). The MAX6855UK44D6+T pinout lacks WDI, confirming absence of watchdog circuitry.

What is the reset output configuration of the MAX6855UK44D6+T?

The MAX6855UK44D6+T features an active-high push-pull RESET output (Pin 1), as confirmed by its position in the Selector Guide and Pin Description table. Unlike open-drain or active-low variants, this output drives high during reset assertion and sinks current when deasserted - eliminating need for external pullup resistors and simplifying interface to µPs requiring active-high reset signals.

How does the MR input behave on the MAX6855UK44D6+T?

The MR input (Pin 3) on the MAX6855UK44D6+T is active-low with internal 10kΩ pullup to VCC, requiring <0.3×VCC to assert reset. It accepts CMOS logic levels, rejects <200ns glitches, and imposes a 1µs minimum pulse width. When MR is held low, RESET remains asserted for the full 600–1200ms timeout after MR returns high - a behavior explicitly defined for MAX6855 in the Pin Description and Detailed Description sections.

Is the MAX6855UK44D6+T compatible with other SOT23-5 supervisory ICs?

The MAX6855UK44D6+T shares the same 5-pin SOT23-5 footprint and pinout (RESET–GND–MR–GND–VCC) as MAX6854/MAX6856 variants but is not pin-compatible with TPS3836/TPS3837/TPS3838 due to differing RESET polarity and internal pullup structure. Direct substitution requires verification of reset signal polarity, MR handling, and threshold match - the MAX6855UK44D6+T is optimized for active-high reset systems with manual recovery.