Analog Devices Inc./Maxim Integrated MAX6855UK31D6+T

Overview

The MAX6855UK31D6+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 3.075V reset threshold (suffix "31"). It delivers ultra-low 170nA typical supply current, 600ms–1200ms reset timeout (D6 option), and guaranteed reset validity down to VCC = +1.1V. It is used in battery-powered glucose monitors and portable medical devices to ensure reliable power-on reset and brownout protection.

For engineers reviewing the MAX6855UK31D6+T datasheet, MAX6855UK31D6+T pinout, MAX6855UK31D6+T application, or MAX6855UK31D6+T equivalent, key selection criteria include its active-high push-pull RESET logic, 3.075V threshold tolerance (±2.5%), 600–1200ms D6 timeout range, MR input with 10kΩ internal pullup, and operation across –40°C to +85°C.

Technical Context

This device integrates voltage monitoring, manual reset assertion, and reset timing control-without watchdog or CT functionality (confirmed by Selector Guide: MAX6855 has MR = √, WDI = -, CT = -). Its reset assertion is triggered solely by VCC falling below 3.075V or MR low, with deassertion delayed by the D6 timeout (600–1200ms) after VCC rises above threshold and MR releases.

The active-high push-pull RESET output is referenced to VCC and guarantees VOH ≥ 0.8×VCC (at ISOURCE = 500µA, VCC ≥ 2.38V) and VOL ≤ 0.3V (at ISINK = 1.2mA, VCC ≥ 2.38V). Immunity to short VCC transients (<40µs for 100mV overdrive) and guaranteed operation down to VCC = 1.1V support robust deployment in low-voltage, noise-sensitive portable systems.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3837K33DBVR and MAX6315US31D3+T, the MAX6855UK31D6+T provides longer D6 timeout (600–1200ms) and active-high push-pull output-enabling direct, polarity-matched connection to modern low-voltage MCUs without level translation or pullup resistors.

Availability

MAX6855UK31D6+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign loggers, and handheld medical diagnostics requiring stable component supply across extended product lifecycles.

Supply support for MAX6855UK31D6+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, mixed-signal, and power management ICs for industrial, medical, and communications applications.

The MAX685x family targets ultra-low-power supervisory functions in battery-critical portable medical and consumer devices, emphasizing nanoscale current consumption and guaranteed low-VCC reset validity.

FAQ

What is the exact reset threshold voltage of the MAX6855UK31D6+T?

The MAX6855UK31D6+T has a factory-trimmed reset threshold of 3.075V, with ±2.5% tolerance over temperature (–40°C to +85°C). This value is confirmed by Table 2 (Threshold Suffix Guide) where suffix "31" maps to min/typ/max = 2.998V/3.075V/3.152V. The MAX6855UK31D6+T uses this threshold to assert reset when VCC falls below 3.075V, making it ideal for 3.3V system brownout detection.

Does the MAX6855UK31D6+T include a watchdog timer function?

No, the MAX6855UK31D6+T does not include a watchdog timer. Per the Selector Guide, MAX6855 has WDI = - (not present). The MAX6855UK31D6+T provides only voltage monitoring, manual reset (MR), and fixed D6 reset timeout. Watchdog capability is exclusive to MAX6864–MAX6869 variants. For designs requiring watchdog supervision, consider MAX6864UK31D6S+T instead.

What is the function of Pin 1 on the MAX6855UK31D6+T?

Pin 1 of the MAX6855UK31D6+T is the active-high push-pull RESET output. When asserted (i.e., during reset condition), it drives high; when deasserted, it drives low. This differs from open-drain or active-low variants. The MAX6855UK31D6+T's Pin 1 directly interfaces with µP reset inputs expecting active-high logic, eliminating need for external inverters or pullup resistors.

How does the D6 suffix in MAX6855UK31D6+T affect reset timing?

The "D6" suffix specifies the reset timeout period option: 600ms (min), 900ms (typ), and 1200ms (max) after VCC rises above threshold and MR deasserts. This extended hold-off ensures complete power-rail stabilization and clock circuit readiness before releasing the µP from reset. The MAX6855UK31D6+T's D6 timeout is significantly longer than D1 (10–25ms) or D3 (150–300ms), supporting complex low-power SoCs with multi-stage power sequencing.

Is the MAX6855UK31D6+T compatible with standard SOT23-5 footprints?

Yes, the MAX6855UK31D6+T uses a standard 5-pin SOT23-5 package with 0.95mm pitch and 1.6mm × 2.9mm body dimensions, fully compatible with IPC-7351B SOT-23-5 land patterns. Pin 1 is top-left (marking dot), Pin 2 and Pin 4 are both GND (dual ground for noise reduction), Pin 3 is MR, and Pin 5 is VCC - matching the MAX6855 pin configuration shown in the datasheet's Pin Configurations diagram.