Analog Devices Inc./Maxim Integrated MAX6855UK29D3+T

Overview

The MAX6855UK29D3+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 2.925V reset threshold with 150ms minimum 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 used in battery-powered glucose monitors and portable medical devices requiring ultra-low quiescent current.

For engineers reviewing the MAX6855UK29D3+T datasheet, MAX6855UK29D3+T pinout, MAX6855UK29D3+T application, or MAX6855UK29D3+T equivalent, key selection criteria include its 2.925V threshold accuracy, 150ms reset timeout, active-high push-pull output logic, MR input compatibility with CMOS levels, and guaranteed operation at VCC ≥ 1.1V - all critical for low-voltage, long-battery-life embedded systems.

Technical Context

This device implements a precision voltage monitor with ±2.5% threshold tolerance over –40°C to +85°C, combined with a digital reset timer that holds RESET high for ≥150ms after VCC recovers above 2.925V and MR deasserts. Its internal 10kΩ MR pullup enables direct switch-to-ground interface without external components.

The active-high push-pull RESET output is referenced to VCC and delivers VOH ≥ 0.8×VCC at ISOURCE = 500µA (VCC ≥ 2.38V), while VOL ≤ 0.3V at ISINK = 1.2mA (VCC ≥ 2.38V). Immunity to short VCC transients (<40µs for 100mV overdrive) ensures robust operation in noisy power environments.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5 (lead-free, +T suffix), footprint-compatible with industry-standard 5-lead SOT23 layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3837K29 and MAX6315US29D3+, the MAX6855UK29D3+T offers the lowest ICC (170nA vs. 800nA–1.6µA), active-high push-pull output eliminating external components, and tighter threshold tolerance (±2.5% vs. ±3%), making it optimal for new ultra-low-power medical and portable designs.

Availability

MAX6855UK29D3+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitoring devices, and MP3 players requiring stable component supply with guaranteed long-term availability and lead-free compliance.

Supply support for MAX6855UK29D3+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, sensing, and interface applications in industrial, medical, and consumer markets.

The MAX6855UK29D3+T belongs to the nanopower µP supervisory family engineered specifically for battery-critical portable electronics where sub-microamp ICC, guaranteed low-VCC reset validity, and minimal external components are essential.

FAQ

What is the exact reset threshold voltage of the MAX6855UK29D3+T?

The MAX6855UK29D3+T has a factory-trimmed reset threshold of 2.925V, 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 "29" corresponds to 2.925V (min 2.852V, typ 2.925V, max 2.998V). The MAX6855UK29D3+T maintains this accuracy without calibration.

Does the MAX6855UK29D3+T include a watchdog timer function?

No, the MAX6855UK29D3+T does not include a watchdog timer. Per the Selector Guide and Pin Description sections, only MAX6864–MAX6869 variants feature WDI input; the MAX6855UK29D3+T is a manual-reset-only supervisory circuit with MR input and no watchdog capability. Its functionality is limited to VCC monitoring and manual reset assertion.

What is the reset timeout period for the MAX6855UK29D3+T?

The MAX6855UK29D3+T has a minimum reset timeout period of 150ms, with typical 225ms and maximum 300ms values. This is defined by the "D3" suffix in the part number and confirmed in Table 4 (Reset Timeout Periods), where D3 maps to 150/225/300ms. The timeout begins after VCC rises above 2.925V and MR is deasserted.

Is the RESET output of the MAX6855UK29D3+T push-pull or open-drain?

The MAX6855UK29D3+T features an active-high push-pull RESET output, as specified in the MAX6855 column of the Pin Description table (Page 7) and Selector Guide (Page 16). It drives high to VCC and low to GND without requiring an external pullup resistor, distinguishing it from open-drain variants like MAX6856.

What package type and lead finish does the MAX6855UK29D3+T use?

The MAX6855UK29D3+T uses a 5-pin SOT23-5 package with lead-free (RoHS-compliant) finish, indicated by the "+T" suffix per Maxim's ordering conventions. Its footprint matches standard SOT23-5 land patterns, and absolute maximum ratings confirm 571mW power dissipation at +70°C ambient.