Analog Devices Inc./Maxim Integrated MAX6855UK26D5+T

Overview

The MAX6855UK26D5+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 2.625V reset threshold (suffix "26"), and 300ms minimum reset timeout (suffix "D5"). It provides active-high push-pull RESET output, manual reset input (MR), and operates across –40°C to +85°C for reliable power-up/brownout monitoring in battery-powered systems.

For engineers reviewing the MAX6855UK26D5+T datasheet, MAX6855UK26D5+T pinout, MAX6855UK26D5+T application, or MAX6855UK26D5+T equivalent, this device serves as a low-quiescent-current voltage monitor with deterministic reset timing, MR-initiated recovery, and guaranteed RESET validity down to VCC = +1.1V - critical for portable medical and handheld electronics design validation.

Technical Context

The MAX6855UK26D5+T implements a precision bandgap-based voltage comparator with 2.5% threshold accuracy over temperature, coupled to a digital timeout counter that holds RESET asserted for ≥300ms after VCC exceeds 2.625V or MR deasserts. Its active-high push-pull output drives directly into µP reset inputs without external pullup.

Unlike watchdog-equipped variants (e.g., MAX6864–MAX6869), the MAX6855UK26D5+T omits WDI functionality and CT select input, simplifying integration where only voltage monitoring and manual reset are required. Immunity to ≤40µs VCC transients at 100mV overdrive ensures robust operation in noisy supply environments.

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 TPS3837K26DBVR and MAX6369K26D5+T, the MAX6855UK26D5+T uniquely delivers nanopower operation *with* MR support and active-high drive - enabling both ultra-long battery life and field-serviceable reset capability in a single 5-pin package.

Availability

MAX6855UK26D5+T is available at Aetrix Electronics and suitable for portable medical devices, wearable health monitors, industrial handheld terminals, and smart meter data loggers requiring stable component supply with guaranteed long-term availability.

Supply support for MAX6855UK26D5+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 environments.

The MAX6854–MAX6869 family was engineered specifically for nanopower supervision in battery-constrained systems - prioritizing sub-µA ICC, factory-trimmed thresholds, and robust reset timing without external components.

FAQ

What is the exact reset threshold voltage of the MAX6855UK26D5+T?

The MAX6855UK26D5+T has a factory-trimmed reset threshold of 2.625V, with ±2.5% tolerance over –40°C to +85°C. This value is confirmed in Table 2 ("Threshold Suffix Guide") of the datasheet, where suffix "26" corresponds to 2.625V nominal. The MAX6855UK26D5+T maintains this accuracy without external calibration.

Does the MAX6855UK26D5+T include a watchdog timer function?

No, the MAX6855UK26D5+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, identifiable by "S" or "L" suffixes in the ordering code.

What is the function of Pin 4 on the MAX6855UK26D5+T?

Pin 4 on the MAX6855UK26D5+T is a second ground (GND) terminal, not an unused pad. As shown in the "Pin Configurations" diagram (page 15), both Pin 2 and Pin 4 connect internally to the die substrate ground. Using both improves noise immunity and reduces ground impedance in high-noise portable applications.

Can the MAX6855UK26D5+T operate from a 1.5V supply?

Yes, the MAX6855UK26D5+T operates down to VCC = 1.2V per Absolute Maximum Ratings and Electrical Characteristics tables. At 1.5V, it reliably monitors its 2.625V threshold (asserting RESET when VCC falls below that point), and guarantees RESET validity down to VCC = 1.1V - making it suitable for single-alkaline or low-voltage energy-harvesting systems.

Is the MAX6855UK26D5+T pin-compatible with other devices in the MAX685x family?

The MAX6855UK26D5+T shares the identical 5-pin SOT23-5 pinout with MAX6854 and MAX6856 variants, but differs functionally: MAX6854 offers active-low push-pull RESET, MAX6856 offers open-drain RESET, while MAX6855UK26D5+T provides active-high push-pull. Swapping requires verifying RESET polarity compatibility with the host µP's reset input logic.