Analog Devices Inc./Maxim Integrated MAX6855UK34D4+T

Overview

The MAX6855UK34D4+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, providing voltage monitoring, manual reset input (MR), and active-low push-pull reset output. It asserts reset when VCC drops below its factory-trimmed 3.4V threshold (±2.5%), MR is pulled low, or - per family capability - watchdog timer expires (though MAX6855 lacks WDI). Designed for ultra-low-power systems, it draws only 170nA typical supply current and guarantees valid reset down to VCC = +1.1V.

For engineers reviewing the MAX6855UK34D4+T datasheet, MAX6855UK34D4+T pinout, MAX6855UK34D4+T application, or MAX6855UK34D4+T equivalent, this device serves as a precision, low-quiescent-current reset supervisor for battery-powered medical and portable electronics where supply stability, timing predictability, and minimal power overhead are critical selection criteria.

Technical Context

The MAX6855UK34D4+T implements a precision bandgap-based voltage monitor with 2.5% threshold tolerance over –40°C to +85°C, paired with a fixed 1200ms minimum reset timeout period (D4 option). Its push-pull active-high RESET output is referenced to VCC and sinks up to 1.2mA at VCC ≥ 2.38V while maintaining VOH ≥ 0.8×VCC.

It features an internally pulled-up MR input (10kΩ) with 250ns MR-to-reset delay and 1µs minimum pulse width support. Immunity to short VCC transients is ensured via built-in glitch rejection, and operation is guaranteed down to VCC = +1.1V - enabling reliable supervision during deep brownout conditions.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount, footprint-compatible with industry-standard 5-pin SOT23 layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3837K33DBVR and MAX6361KA29D3+T, the MAX6855UK34D4+T delivers superior energy efficiency (170nA vs. >1µA), exact 3.4V threshold alignment for 3.3V systems, and active-high push-pull drive - reducing component count and enabling direct interface with modern low-voltage µPs.

Availability

MAX6855UK34D4+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, MP3 players, and cell phones requiring stable component supply with guaranteed long-term availability and lead-free compliance.

Supply support for MAX6855UK34D4+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 nanopower microprocessor supervision in battery-critical systems, emphasizing ultra-low ICC, precise voltage thresholds, and robust reset timing under brownout conditions.

FAQ

What is the exact reset threshold voltage of the MAX6855UK34D4+T?

The MAX6855UK34D4+T has a factory-trimmed reset threshold of 3.400V 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 "34" corresponds to 3.400V nominal. The MAX6855UK34D4+T uses this exact threshold to supervise 3.3V rails with appropriate margin against noise and dropout.

Does the MAX6855UK34D4+T include a watchdog timer function?

No, the MAX6855UK34D4+T does not include a watchdog timer. Per the Selector Guide and Pin Description sections, only MAX6864–MAX6869 variants feature WDI input; MAX6855 belongs to the MR-only subgroup (no WDI pin, no watchdog circuitry). The MAX6855UK34D4+T provides voltage monitoring and manual reset only - confirming its role as a dedicated supervisor without watchdog functionality.

What is the reset timeout period for the MAX6855UK34D4+T?

The MAX6855UK34D4+T has a fixed minimum reset timeout period of 1200ms, indicated by the "D4" suffix in its part number. Table 4 (Reset Timeout Periods) specifies D4 as 1200ms (min) / 1800ms (typ) / 2400ms (max). This extended timeout ensures reliable µP initialization in complex embedded systems where firmware boot sequences exceed 1 second.

What type of reset output does the MAX6855UK34D4+T provide?

The MAX6855UK34D4+T provides an active-high push-pull reset output, as confirmed by the MAX6855 column in the Pin Description table (Pin 1 = RESET, "Active-High Push-Pull") and the Selector Guide. This eliminates the need for an external pullup resistor and allows direct driving of µP reset inputs requiring high-assertion logic levels - a key differentiator from open-drain or active-low variants.

Is the MAX6855UK34D4+T compatible with standard SOT23-5 footprints?

Yes, the MAX6855UK34D4+T uses a standard 5-pin SOT23-5 package, as explicitly stated in the Ordering Information table and verified in the Pin Configurations diagram. Its mechanical dimensions, pad layout, and thermal characteristics match JEDEC MO-178AB, ensuring drop-in compatibility with existing SOT23-5 assembly processes and reflow profiles.