Analog Devices Inc./Maxim Integrated MAX6855UK23D1+T

Overview

The MAX6855UK23D1+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, a factory-trimmed 2.313V reset threshold (suffix D1), and a 10ms minimum reset timeout period. It provides active-high push-pull RESET output, manual reset input (MR), and voltage monitoring for brownout detection - used to ensure reliable power-up sequencing in battery-powered medical and portable electronics.

For engineers reviewing the MAX6855UK23D1+T datasheet, MAX6855UK23D1+T pinout, MAX6855UK23D1+T application, or MAX6855UK23D1+T equivalent, key selection criteria include guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), MR glitch rejection (200ns), and compatibility with 1.2V–5.5V supply rails.

Technical Context

This device implements a precision bandgap-based voltage monitor with 2.5% threshold accuracy and 0.5% hysteresis, combined with a digital reset timeout timer and CMOS-compatible manual reset logic. The internal 10kΩ MR pullup enables direct switch-to-GND implementation without external components.

The active-high push-pull RESET output is referenced to VCC and delivers VOH ≥ 0.8×VCC (at ISOURCE = 500µA) and VOL ≤ 0.3V (at ISINK = 1.2mA), ensuring robust interface with µP reset inputs across its full 1.2V–5.5V operating range.

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 TPS3837K23DBVR and MAX6361KA23D1+T, the MAX6855UK23D1+T offers the lowest supply current (170nA vs. >1µA), active-high push-pull output eliminating external components, and tighter threshold accuracy - making it optimal for ultra-low-power medical and portable designs where every nanoamp counts.

Availability

MAX6855UK23D1+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered PDAs, MP3 players, and patient monitors requiring stable component supply with long-term lifecycle support.

Supply support for MAX6855UK23D1+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 timing applications, with emphasis on low-power, high-reliability solutions.

The MAX685x family targets nanopower supervisory needs in battery-critical systems, delivering ultra-low ICC, wide VCC range, and guaranteed reset behavior down to 1.1V - specifically engineered for medical, portable, and energy-harvesting applications.

FAQ

What is the exact reset threshold voltage of the MAX6855UK23D1+T?

The MAX6855UK23D1+T has a factory-trimmed reset threshold voltage of 2.313V (typical), with ±2.5% tolerance over temperature. This value is defined by the "23" suffix per Maxim's Threshold Suffix Guide (Table 2), and is guaranteed valid from -40°C to +85°C. The MAX6855UK23D1+T maintains this precision without external calibration.

Does the MAX6855UK23D1+T include a watchdog timer function?

No, the MAX6855UK23D1+T does not include a watchdog timer. It belongs to the MAX6854/MAX6855/MAX6856 subgroup, which provides voltage monitoring and manual reset only. Watchdog functionality is exclusive to MAX6864–MAX6869 variants (e.g., MAX6864UK23D1S+T). The MAX6855UK23D1+T pinout and functional diagram confirm absence of WDI terminal.

What is the reset output configuration of the MAX6855UK23D1+T?

The MAX6855UK23D1+T features an active-high push-pull RESET output (Pin 1), as confirmed by its "55" part number in the Selector Guide and Pin Description table. This means RESET goes high during fault conditions and returns low after timeout. It sources/sinks up to 500µA while maintaining VOH ≥ 0.8×VCC and VOL ≤ 0.3V - enabling direct drive of µP reset pins without external components.

Can the MAX6855UK23D1+T operate reliably below 1.8V?

Yes, the MAX6855UK23D1+T operates from 1.2V to 5.5V and guarantees valid reset assertion down to VCC = +1.1V. Its 170nA typical supply current at 1.8V scales downward at lower voltages, supporting single-cell NiMH or low-Vf LiFePO₄ batteries. Electrical Characteristics tables explicitly specify parameters at VCC = 1.2V, confirming sub-1.8V functionality.

Is the MAX6855UK23D1+T pin-compatible with other MAX685x devices?

The MAX6855UK23D1+T shares the same 5-pin SOT23-5 package and pinout (RESET, GND, MR, GND, VCC) with MAX6854 and MAX6856 variants, but differs in reset polarity: MAX6854 is active-low push-pull, MAX6855UK23D1+T is active-high push-pull, and MAX6856 is open-drain. Swapping requires verifying µP reset pin polarity and pullup requirements - it is not a drop-in replacement without schematic review.