Analog Devices Inc./Maxim Integrated MAX6855UK19D2+T

Overview

The MAX6855UK19D2+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, a factory-trimmed 1.9V reset threshold (±2.5%), and a 40ms minimum reset timeout period. It provides active-high push-pull RESET output, manual reset input (MR), and voltage monitoring for brownout detection - used to ensure reliable power-up sequencing in battery-powered medical and portable electronics.

For engineers reviewing the MAX6855UK19D2+T datasheet, MAX6855UK19D2+T pinout, MAX6855UK19D2+T application, or MAX6855UK19D2+T equivalent, this page delivers verified functional identity, validated pin-level behavior, confirmed timing parameters, and real-world design context for low-power µP reset management in constrained environments.

Technical Context

This device operates across VCC = 1.2V to 5.5V and guarantees valid RESET assertion down to VCC = 1.1V. Its internal reset generator uses a precision bandgap reference and hysteresis (0.5% of VTH) to reject short VCC transients - immune to ≤40µs glitches at 100mV overdrive.

The MR input features 10kΩ internal pullup, 1µs minimum pulse width, and 200ns glitch rejection. RESET output is push-pull active-high with VOH ≥ 0.8×VCC (at ISOURCE = 500µA) and VOL ≤ 0.3V (at ISINK = 1.2mA), referenced directly to VCC.

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 MAX6315US29D2+T, the MAX6855UK19D2+T uniquely delivers 1.9V precision thresholding with sub-µA current - essential for long-life 1.8–2.0V battery systems where every nanoamp impacts field service interval.

Availability

MAX6855UK19D2+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered PDAs, MP3 players, and low-power sensor nodes requiring stable component supply across multi-year production cycles.

Supply support for MAX6855UK19D2+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 - with emphasis on performance, integration, and reliability.

The MAX6855UK19D2+T belongs to the MAX685x nanopower supervisory family, engineered specifically for ultra-low-power reset control in battery-critical applications such as medical wearables and portable instrumentation.

FAQ

What is the exact reset threshold voltage of the MAX6855UK19D2+T?

The MAX6855UK19D2+T has a factory-trimmed reset threshold of 1.900V 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 "19" corresponds to 1.9V nominal. The device guarantees valid reset assertion down to VCC = 1.1V, making it suitable for shallow brownout detection in low-voltage systems.

Does the MAX6855UK19D2+T include a watchdog timer?

No, the MAX6855UK19D2+T does not include a watchdog timer. It belongs to the MAX6854/MAX6855/MAX6856 subgroup, which provides voltage monitoring and manual reset only. Watchdog functionality is exclusive to MAX6864–MAX6869 variants (e.g., MAX6864UK19D2S+T). The MAX6855UK19D2+T pinout omits WDI, and its functional diagram excludes watchdog circuitry.

What is the function of Pin 4 on the MAX6855UK19D2+T?

Pin 4 on the MAX6855UK19D2+T is a second GND terminal - not a no-connect or internally connected pin. Per the MAX6854/MAX6855/MAX6856 Pin Description table and SOT23 top-view diagram, Pins 2 and 4 are both labeled GND and must be connected to the same system ground potential. This dual-GND configuration improves noise immunity and thermal dissipation in the 5-pin SOT23 package.

Can the MAX6855UK19D2+T drive a 3.3V microcontroller reset input?

Yes, the MAX6855UK19D2+T can directly drive a 3.3V microcontroller reset input. Its push-pull active-high RESET output delivers VOH ≥ 0.8×VCC (e.g., ≥2.64V at VCC = 3.3V) with ISOURCE = 500µA, meeting standard 3.3V CMOS high-level input requirements. No level-shifter or pullup resistor is needed - the output is rail-referenced and fully compatible with 3.3V logic interfaces.

What is the minimum reset timeout period for the MAX6855UK19D2+T?

The MAX6855UK19D2+T has a minimum reset timeout period of 40ms, corresponding to the "D2" suffix in its part number. This is confirmed in Table 4 (Reset Timeout Periods), where D2 specifies 40ms (min), 60ms (typ), and 80ms (max). The timeout begins after VCC rises above the 1.9V threshold and MR is deasserted, ensuring sufficient hold time for µP core and memory initialization.