Analog Devices Inc./Maxim Integrated MAX6855UK40D6+T

Overview

The MAX6855UK40D6+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 4.000V reset threshold (suffix "40"), and 600ms–1200ms minimum reset timeout (suffix "D6"). It provides active-high push-pull RESET output, manual reset input (MR), and operates across –40°C to +85°C for battery-powered medical and portable electronics.

For engineers reviewing the MAX6855UK40D6+T datasheet, MAX6855UK40D6+T pinout, MAX6855UK40D6+T application, or MAX6855UK40D6+T equivalent, this page delivers verified functional identity, exact pin roles, confirmed timing behavior, and validated alternative options - all aligned with Maxim's official electrical characteristics and pin configuration data.

Technical Context

This device monitors VCC against a precise 4.000V threshold and asserts an active-high RESET signal when voltage drops below that level, MR is pulled low, or (in watchdog variants) WDI stalls - but the MAX6855UK40D6+T excludes watchdog functionality. Its internal timer guarantees RESET remains asserted for ≥600ms after VCC recovers above threshold and MR deasserts.

Designed for brownout immunity, it maintains valid RESET down to VCC = +1.1V and rejects short VCC transients (e.g., ≤40µs at 100mV overdrive). The MR input features 10kΩ internal pullup, 1µs minimum pulse width, and 200ns glitch rejection - enabling direct interface with momentary switches or CMOS logic without external components.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free (RoHS-compliant), 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 MAX6369KA29D3+T, the MAX6855UK40D6+T uniquely combines 4.000V precision threshold, active-high push-pull drive, manual reset support, and nanopower operation - making it the sole fit for new 4.0V battery-powered medical devices requiring guaranteed reset hold time and field-serviceable reset initiation.

Availability

MAX6855UK40D6+T is available at Aetrix Electronics and suitable for portable glucose monitors, patient vital sign loggers, and industrial handheld scanners requiring stable component supply, long-lifecycle assurance, and RoHS-compliant packaging.

Supply support for MAX6855UK40D6+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 communications markets.

The MAX6855UK40D6+T belongs to the nanopower µP supervisory family, engineered specifically for ultra-low-power battery-operated systems where extended runtime and reliable power-on reset behavior are critical.

FAQ

What is the exact reset threshold voltage of the MAX6855UK40D6+T?

The MAX6855UK40D6+T has a factory-trimmed reset threshold of 4.000V ±2.5%, as indicated by the "40" suffix in its part number. This value is guaranteed over the full –40°C to +85°C operating temperature range and enables precise supervision of 3.3V/4.0V rails without external calibration. The MAX6855UK40D6+T maintains this accuracy via on-chip trimming and is validated per Maxim's Electrical Characteristics table.

Does the MAX6855UK40D6+T include a watchdog timer function?

No, the MAX6855UK40D6+T does not include a watchdog timer. It belongs to the MAX6854/MAX6855/MAX6856 subgroup, which provides voltage monitoring and manual reset only. Watchdog capability is exclusive to MAX6864–MAX6869 variants (e.g., MAX6864UKxxDxxS+T). The MAX6855UK40D6+T pinout omits WDI, and its functional diagram confirms absence of watchdog circuitry.

What is the RESET output configuration of the MAX6855UK40D6+T?

The MAX6855UK40D6+T features an active-high push-pull RESET output (Pin 1), as confirmed by its MAX6855 designation in the Selector Guide and Pin Description table. It sources ≥0.8×VCC at 500µA and sinks ≤0.3V at 1.2mA, eliminating need for external pullup resistors. This differs from MAX6854 (active-low push-pull) and MAX6856 (active-low open-drain) variants.

What is the minimum reset timeout period for the MAX6855UK40D6+T?

The MAX6855UK40D6+T has a minimum reset timeout period of 600ms, specified by the "D6" suffix. Per Table 4, D6 corresponds to 600ms (min) / 900ms (typ) / 1200ms (max). This timeout begins after VCC rises above 4.000V and MR is deasserted, ensuring sufficient hold time for slow-starting µPs and peripherals before release.

Is the MAX6855UK40D6+T pin-compatible with other SOT23-5 supervisory ICs?

The MAX6855UK40D6+T uses standard 5-pin SOT23-5 pinout (VCC–GND–MR–GND–RESET), matching industry layout conventions. However, it is not pin-compatible with TPS3836/TPS3837/TPS3838 due to differing RESET polarity and pin assignments - those TI parts place RESET on Pin 1 (active-low) and lack dual-GND configuration. Direct substitution requires PCB revision.