Analog Devices Inc./Maxim Integrated MAX6855UK34D3+T

Overview

The MAX6855UK34D3+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, providing active-high push-pull reset output, manual reset input (MR), and factory-trimmed 3.400V reset threshold with 150ms minimum reset timeout. It monitors VCC for brownout detection, asserts reset during power-up/down, and guarantees valid reset operation down to VCC = +1.1V. Used in battery-powered medical and portable electronics where ultra-low quiescent current is critical.

For engineers reviewing the MAX6855UK34D3+T datasheet, MAX6855UK34D3+T pinout, MAX6855UK34D3+T application, or MAX6855UK34D3+T equivalent, key selection criteria include its 170nA typical supply current, 3.400V ±2.5% reset threshold, 150ms reset timeout, MR input with 10kΩ internal pullup, and guaranteed reset validity at VCC ≥ 1.1V in -40°C to +85°C industrial temperature range.

Technical Context

This device implements a precision voltage monitor with hysteresis (0.5% of VTH) and a fixed-timing reset timeout generator. Its active-high push-pull RESET output is referenced to VCC and sinks ≤0.3V at 1.2mA load when asserted, while sourcing ≥0.8×VCC at 500µA when deasserted.

The MR input accepts CMOS-compatible logic levels (VIH ≥ 0.7×VCC, VIL ≤ 0.3×VCC), features 200ns glitch rejection, and triggers reset with ≥1µs pulse width. No external components are required beyond standard 0.1µF VCC bypass capacitance.

Key Specifications

Pinout & Package

5-pin SOT23-5 package with exposed pad (not electrically connected); footprint compatible with industry-standard 5-lead SOT23 assembly processes.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3837K33DBVR and MAX6369KA29D3+T, the MAX6855UK34D3+T uniquely delivers 3.400V threshold accuracy, MR support, and 170nA ICC in a 5-pin SOT23-making it optimal for long-life, manually resettable 3.3V systems where every nanoamp counts.

Availability

MAX6855UK34D3+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, smart wearables, and industrial handheld terminals requiring stable component supply across extended production lifecycles.

Supply support for MAX6855UK34D3+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 communications applications.

The MAX6854–MAX6869 family was designed specifically for ultra-low-power microprocessor supervision in battery-critical portable medical and consumer devices, emphasizing nanoscale ICC, precise voltage thresholds, and robust reset timing.

FAQ

What is the exact reset threshold voltage of the MAX6855UK34D3+T?

The MAX6855UK34D3+T has a factory-trimmed reset threshold of 3.400V 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 "34" corresponds to 3.400V nominal. The device guarantees valid reset assertion down to VCC = +1.1V, making it suitable for deep brownout detection in 3.3V systems.

Does the MAX6855UK34D3+T include a watchdog timer function?

No, the MAX6855UK34D3+T does not include a watchdog timer. Per the Selector Guide and Pin Configurations section, only MAX6864–MAX6869 variants feature WDI input; the MAX6855 series provides voltage monitoring, manual reset (MR), and fixed reset timeout only. The "55" in the part number denotes active-high push-pull RESET output without watchdog capability-confirmed by absence of WDI pin in its pinout diagram.

What is the function of Pin 1 on the MAX6855UK34D3+T?

Pin 1 of the MAX6855UK34D3+T is the RESET output terminal, configured as an active-high push-pull driver. When deasserted, it sources ≥0.8×VCC at 500µA; when asserted (during reset), it sinks to ≤0.3V at 1.2mA. This pin directly interfaces with the microprocessor's active-high reset input, eliminating need for external level-shifting or pullup resistors-unlike open-drain variants in the same family.

How does the manual reset (MR) input behave on the MAX6855UK34D3+T?

The MR input on the MAX6855UK34D3+T is active-low with internal 10kΩ pullup to VCC. Driving MR low for ≥1µs initiates reset, holding the RESET output high for the full 150ms timeout period even after MR returns high. Glitch rejection filters pulses <200ns. If unused, MR may be left floating (due to internal pullup) or tied to VCC; no external components are required for basic operation.

Is the MAX6855UK34D3+T RoHS-compliant and lead-free?

Yes, the MAX6855UK34D3+T is lead-free and RoHS-compliant. The "+T" suffix explicitly denotes lead-free packaging per Maxim's ordering conventions (stated in Ordering Information: "Specify lead-free by replacing '-T' with '+T' when ordering"). It uses matte tin finish on terminals and meets JEDEC J-STD-020 moisture sensitivity level 1 requirements for reflow soldering.