Analog Devices Inc./Maxim Integrated MAX6855UK23D3+T

Overview

The MAX6855UK23D3+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring active-high push-pull reset output, manual reset input (MR), and factory-trimmed 2.313V reset threshold with 225ms minimum reset timeout. It monitors VCC supply integrity, asserts reset during brownout or manual trigger, and guarantees valid reset operation down to VCC = +1.1V. Used in ultra-low-power portable medical and consumer devices where supply stability and deterministic reset timing are critical.

For engineers reviewing the MAX6855UK23D3+T datasheet, MAX6855UK23D3+T pinout, MAX6855UK23D3+T application, or MAX6855UK23D3+T equivalent, this page delivers verified functional identity, exact pin roles, confirmed timing parameters, real-world use cases, and validated alternative options - all extracted from Maxim's official documentation for precise selection and integration.

Technical Context

The MAX6855UK23D3+T implements a voltage-monitoring comparator with 2.5% threshold hysteresis, internal 10kΩ MR pullup, and a fixed 225ms reset timeout timer. Its active-high push-pull RESET output is referenced to VCC and sinks ≤0.3V at 500µA load when asserted, while sourcing ≥0.8×VCC when deasserted.

This variant belongs to the MAX6854–MAX6856 subfamily: it includes MR but no watchdog (WDI) or timeout-select (CT) pins, and uses the UK23 reset threshold suffix (2.313V typ) and D3 timeout option (150–300ms). It is not pin-compatible with MAX6864–MAX6869 or MAX6861–MAX6863 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 MAX6854UK23D3+T and TPS3836K23DBVR, the MAX6855UK23D3+T uniquely delivers active-high reset with nanopower consumption and 1.1V operational guarantee - essential for long-life medical wearables where reset polarity and battery longevity are co-constrained.

Availability

MAX6855UK23D3+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign loggers, portable ultrasound probes, and smart inhaler dosage trackers requiring stable component supply, full RoHS compliance, and guaranteed long-term manufacturability.

Supply support for MAX6855UK23D3+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 management, sensing, and interface applications in industrial, medical, and communications systems.

The MAX6854–MAX6856 family was engineered specifically for ultra-low-power microprocessor supervision in battery-constrained portable medical and consumer electronics, emphasizing nanoscale ICC, guaranteed low-VCC operation, and factory-trimmed accuracy.

FAQ

What is the exact reset threshold voltage of the MAX6855UK23D3+T?

The MAX6855UK23D3+T has a factory-trimmed reset threshold of 2.313V (typical), with ±2.5% tolerance over temperature (–40°C to +85°C). This value is defined by the "23" suffix in the part number per Maxim's Threshold Suffix Guide (Table 2), and is optimized for reliable brownout detection in 2.5V systems. The MAX6855UK23D3+T maintains this accuracy without external calibration.

Does the MAX6855UK23D3+T include a watchdog timer function?

No, the MAX6855UK23D3+T does not include a watchdog timer. It belongs to the MAX6854/MAX6855/MAX6856 subfamily, which provides only voltage monitoring and manual reset (MR) functionality. Watchdog capability is exclusive to MAX6864–MAX6869 variants (e.g., MAX6864UK23D3S+T), identifiable by the "S" or "L" suffix in the ordering code.

What is the function of Pin 1 on the MAX6855UK23D3+T?

Pin 1 of the MAX6855UK23D3+T is the RESET output terminal, configured as an active-high push-pull driver. When asserted (i.e., during power-up, brownout, or MR activation), it drives high to signal reset to the microprocessor. Unlike open-drain variants, it requires no external pullup resistor and interfaces directly with µP reset inputs expecting active-high logic.

Can the MAX6855UK23D3+T operate with a 1.2V supply?

Yes, the MAX6855UK23D3+T is fully specified to operate from VCC = 1.2V to 5.5V. Its reset output remains valid down to VCC = +1.1V, and its 170nA typical supply current is measured at VCC = 1.8V - confirming robust functionality at the lower end of its operating range. This makes the MAX6855UK23D3+T suitable for single-cell lithium or alkaline-powered devices.

Is the MAX6855UK23D3+T pin-compatible with the TPS3836 series?

No, the MAX6855UK23D3+T is not pin-compatible with the TPS3836 series. While both are 5-pin SOT23 supervisors, the TPS3836K23DBVR places RESET on Pin 1 (active-low open-drain) and GND on Pin 2, whereas the MAX6855UK23D3+T uses Pin 1 for active-high push-pull RESET and Pins 2 & 4 for dual GND connections. PCB layout and schematic must be redesigned for substitution.