Analog Devices Inc./Maxim Integrated MAX6855UK33D5+T

Overview

The MAX6855UK33D5+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 3.3V reset threshold (±2.5%). It provides a 300ms minimum reset timeout period and draws only 170nA typical supply current at 2.5V, enabling reliable power-on reset and brownout protection in ultra-low-power portable systems.

For engineers reviewing the MAX6855UK33D5+T datasheet, MAX6855UK33D5+T pinout, MAX6855UK33D5+T application, or MAX6855UK33D5+T equivalent, this device serves as a precision voltage monitor with deterministic reset timing, manual reset initiation, and guaranteed reset validity down to VCC = +1.1V - critical for battery-powered medical and consumer electronics where supply stability and energy efficiency are non-negotiable.

Technical Context

The MAX6855UK33D5+T implements a precision bandgap-based voltage reference and comparator to monitor VCC against its fixed 3.3V threshold. Upon VCC falling below VTH, it asserts an active-high RESET signal that remains asserted for ≥300ms after VCC rises above threshold and MR deasserts.

Its internal 10kΩ MR pullup enables direct connection of a momentary switch to GND without external components, while immunity to ≤40µs VCC transients at 100mV overdrive ensures robust operation in noisy environments. The push-pull RESET output drives high to VCC and sinks up to 1.2mA at 2.38V, eliminating need for external pullups.

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 TPS3837K33DBVR and MAX6315US33D3+T, the MAX6855UK33D5+T delivers superior energy efficiency (170nA vs. >1µA), guaranteed reset functionality down to 1.1V, and integrated manual reset - making it optimal for next-generation battery-constrained medical and wearable systems.

Availability

MAX6855UK33D5+T is available at Aetrix Electronics and suitable for portable medical devices, wearable health monitors, smart remote controls, and low-power IoT sensors requiring stable component supply and long-term lifecycle support.

Supply support for MAX6855UK33D5+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 demanding industrial, medical, and consumer systems.

The MAX6855UK33D5+T belongs to the MAX68xx nanopower supervisory family, engineered specifically for ultra-low-power battery-operated equipment where reset reliability and energy conservation are critical design constraints.

FAQ

What is the exact reset threshold voltage of the MAX6855UK33D5+T?

The MAX6855UK33D5+T has a factory-trimmed reset threshold voltage of 3.3V with ±2.5% tolerance over the full -40°C to +85°C temperature range. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "33" corresponds to 3.3V nominal, and electrical characteristics specify VTH = 3.218V (min) to 3.383V (max) at TA = -40°C to +85°C.

Does the MAX6855UK33D5+T include a watchdog timer function?

No, the MAX6855UK33D5+T does not include a watchdog timer. Per the Selector Guide and Pin Description sections, only MAX6864–MAX6869 variants feature WDI input; the MAX6855UK33D5+T is a manual-reset-only supervisory circuit with MR input and active-high push-pull RESET output.

What is the minimum reset timeout period for the MAX6855UK33D5+T?

The MAX6855UK33D5+T has a minimum reset timeout period of 300ms, indicated by the "D5" suffix in its part number. Table 4 (Reset Timeout Periods) confirms D5 = 300ms (min), 450ms (typ), 600ms (max), ensuring sufficient hold time for µP initialization and peripheral configuration.

Can the MAX6855UK33D5+T operate with supply voltages below 1.8V?

Yes, the MAX6855UK33D5+T operates from 1.2V to 5.5V and guarantees valid reset assertion down to VCC = +1.1V. Electrical Characteristics confirm functional operation at 1.2V minimum, and the reset output remains asserted and electrically defined even as VCC falls to 1.1V - critical for detecting end-of-battery-life conditions.

Is the MAX6855UK33D5+T pin-compatible with other MAX68xx supervisory devices?

The MAX6855UK33D5+T shares the same 5-pin SOT23-5 package and pinout (RESET, GND, MR, GND, VCC) with MAX6854, MAX6856, MAX6861–MAX6863, and MAX6864–MAX6869 variants. However, output polarity and feature sets differ: MAX6855UK33D5+T is active-high push-pull, while MAX6854 is active-low push-pull and MAX6856 is active-low open-drain - direct substitution requires verification of reset polarity and load requirements.