Analog Devices Inc./Maxim Integrated MAX6855UK37D2+T

Overview

The MAX6855UK37D2+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 3.700V reset threshold with 120ms typical reset timeout. It monitors VCC supply integrity, asserts reset during brownout or manual trigger, and guarantees valid reset operation down to VCC = +1.1V. It is designed for ultra-low-power portable systems where supply stability and deterministic reset timing are critical.

For engineers reviewing the MAX6855UK37D2+T datasheet, MAX6855UK37D2+T pinout, MAX6855UK37D2+T application, or MAX6855UK37D2+T equivalent, this page delivers verified electrical parameters, confirmed pin functions, real-world use cases in battery-powered medical and consumer devices, and two validated alternative parts with documented functional and timing differences.

Technical Context

The MAX6855UK37D2+T implements a voltage-monitoring comparator with ±2.5% threshold accuracy over temperature, coupled to a fixed-reset-timeout timer (D2 = 40ms min / 60ms typ / 80ms max). Its active-high push-pull RESET output is referenced to VCC and sinks ≤0.3V at 1.2mA load, ensuring clean logic-level assertion without external pullups.

It includes an internally 10kΩ-pulled-up MR input with 1µs minimum pulse width and 250ns MR-to-reset delay, enabling reliable manual reset initiation. Immunity to short VCC transients (<40µs at 100mV overdrive) and guaranteed operation from VCC = 1.2V to 5.5V support robust deployment in noisy, low-voltage embedded environments.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount, footprint compatible with JEDEC MO-178AB.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6855UK37D2+T, MAX6854UK37D2+T offers identical supervision accuracy and timing but requires external biasing for reset assertion, while TPS3837K33DBVR trades 10× higher supply current for improved threshold precision and longer timeout-making it preferable only when nanopower is not critical.

Availability

MAX6855UK37D2+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitoring devices, and smart pagers requiring stable component supply with long-term lifecycle assurance and lead-free compliance.

Supply support for MAX6855UK37D2+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 portable applications.

The MAX685x family was designed specifically for ultra-low-power microprocessor supervision in battery-critical medical and consumer electronics, emphasizing nanoscale ICC, guaranteed low-VCC operation, and factory-trimmed voltage thresholds.

FAQ

What is the exact reset threshold voltage of the MAX6855UK37D2+T?

The MAX6855UK37D2+T has a factory-trimmed reset threshold voltage of 3.700V, 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 "37" corresponds to 3.608V (min), 3.700V (typ), and 3.793V (max). The MAX6855UK37D2+T uses this exact threshold configuration.

Does the MAX6855UK37D2+T include a watchdog timer?

No, the MAX6855UK37D2+T does not include a watchdog timer. Per the Selector Guide and Pin Description sections, only MAX6864–MAX6869 variants feature WDI functionality. The MAX6855UK37D2+T belongs to the MAX6854/MAX6855/MAX6856 group, which provides voltage monitoring and manual reset only-no watchdog circuitry is present in this specific variant.

What is the reset timeout period for the MAX6855UK37D2+T?

The MAX6855UK37D2+T uses the D2 reset timeout option, specified as 40ms (min), 60ms (typ), and 80ms (max) in Table 4 of the datasheet. This fixed timeout begins after VCC rises above the 3.700V threshold and MR deasserts, ensuring sufficient hold time for microprocessor initialization before release.

What type of reset output does the MAX6855UK37D2+T provide?

The MAX6855UK37D2+T provides an active-high push-pull reset output, as confirmed in the MAX6854/MAX6855/MAX6856 Pin Description table and Selector Guide. Pin 1 is labeled RESET (active-high), and the output drives high during reset assertion without requiring an external pullup resistor-unlike open-drain variants such as MAX6856.

Is the MAX6855UK37D2+T pin-compatible with other parts in the MAX685x family?

The MAX6855UK37D2+T shares the same 5-pin SOT23-5 package and pinout (VCC, GND, MR, GND, RESET) with MAX6854 and MAX6856, but differs functionally: MAX6854 uses active-low open-drain RESET, MAX6856 uses active-low push-pull, while MAX6855UK37D2+T uses active-high push-pull. Physical pin compatibility exists, but RESET logic polarity is not interchangeable without board-level redesign.