Analog Devices Inc./Maxim Integrated MAX6855UK27D6+T

Overview

The MAX6855UK27D6+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 2.7V reset threshold (±2.5%), and 600ms–1200ms minimum reset timeout period. It provides active-low push-pull reset output, manual reset input (MR), and operates across -40°C to +85°C - used in battery-powered glucose monitors and portable medical devices to ensure reliable power-on reset and brownout protection.

For engineers reviewing the MAX6855UK27D6+T datasheet, MAX6855UK27D6+T pinout, MAX6855UK27D6+T application, or MAX6855UK27D6+T equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), MR glitch rejection (200ns), and compatibility with 1.2V–5.5V supply rails in space-constrained portable systems.

Technical Context

This device integrates voltage monitoring, manual reset assertion, and reset timing control in a single BiCMOS IC. Its internal reference and comparator detect VCC falling below 2.7V (VTH), triggering an active-low push-pull RESET signal that remains asserted for ≥600ms after VCC recovers and MR deasserts.

The MR input features a 10kΩ internal pullup and accepts CMOS-compatible logic levels; it initiates reset when pulled low and supports momentary switch interfacing without external debounce. No external components are required for basic operation beyond a 0.1µF VCC bypass capacitor.

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 TPS3836K27DBVR and MAX6369K27+T, the MAX6855UK27D6+T uniquely balances ultra-low ICC (170nA), integrated MR, and 600ms–1200ms configurable timeout - making it optimal for long-life, manually serviceable, space-constrained medical wearables where power and reliability are co-critical.

Availability

MAX6855UK27D6+T is available at Aetrix Electronics and suitable for glucose monitoring systems, patient vital sign monitors, and handheld diagnostic tools requiring stable component supply with full traceability and lifecycle continuity.

Supply support for MAX6855UK27D6+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 industrial, medical, and communications applications, emphasizing low-power, high-reliability performance.

The MAX6855UK27D6+T belongs to the MAX6854–MAX6869 nanopower µP supervisory family, engineered specifically for battery-critical portable medical electronics where sub-µA supply current and guaranteed low-VCC reset behavior are essential.

FAQ

What is the exact reset threshold voltage of the MAX6855UK27D6+T?

The MAX6855UK27D6+T has a factory-trimmed reset threshold of 2.7V 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 "27" corresponds to VTH = 2.7V nominal. The MAX6855UK27D6+T guarantees valid reset assertion down to VCC = +1.1V, independent of threshold drift.

Does the MAX6855UK27D6+T include a watchdog timer function?

No, the MAX6855UK27D6+T does not include a watchdog timer. Per the Selector Guide and Pin Description sections, only MAX6864–MAX6869 variants feature WDI input and watchdog timeout logic. The MAX6855UK27D6+T provides voltage monitoring, manual reset (MR), and fixed reset timeout - confirmed by its pinout (no WDI pin) and functional diagram.

What is the reset timeout period for the MAX6855UK27D6+T, and how is it set?

MAX6855UK27D6+T has a fixed minimum reset timeout period of 600ms, as indicated by suffix "D6" in its part number (Table 4). This timeout is factory-programmed and non-adjustable - unlike MAX6861–MAX6863 which use the CT pin for selection. The 600ms duration ensures sufficient time for power rail stabilization and µP internal initialization before release.

Can the MAX6855UK27D6+T drive a reset pin directly without external components?

Yes, the MAX6855UK27D6+T features an active-low push-pull RESET output, enabling direct connection to most µP reset inputs without external pullup resistors. Its VOL ≤ 0.3V at ISINK = 1.2mA (VCC ≥ 2.12V) and VOH ≥ 0.8 × VCC ensure robust logic-level compatibility. Only a 0.1µF VCC bypass capacitor is required for stable operation.

Is the MAX6855UK27D6+T pin-compatible with other supervisory ICs?

The MAX6855UK27D6+T uses a standard 5-pin SOT23-5 package and shares pinout compatibility with the TPS3836/TPS3837/TPS3838 series (as noted in Features), but differs in MR handling and output polarity. While physical footprint matches, electrical behavior (e.g., push-pull vs. open-drain, MR internal pullup value) requires validation before drop-in replacement - the MAX6855UK27D6+T is not guaranteed pin-and-function compatible.