Analog Devices Inc./Maxim Integrated MAX6855UK25D6+T

Overview

The MAX6855UK25D6+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 2.500V reset threshold with ±2.5% tolerance. It asserts reset during VCC brownout, MR assertion, or watchdog timeout (not applicable to MAX6855), and guarantees valid reset down to VCC = +1.1V. It delivers ultra-low 170nA typical supply current and supports 600ms minimum reset timeout - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6855UK25D6+T datasheet, MAX6855UK25D6+T pinout, MAX6855UK25D6+T application, or MAX6855UK25D6+T equivalent, this page provides verified functional identity, confirmed pin mapping, exact reset threshold and timeout values, real-world timing behavior under temperature variation, and validated alternative options for low-power µP supervision in space-constrained, long-life embedded systems.

Technical Context

The MAX6855UK25D6+T implements a precision voltage monitor with hysteresis (0.5% of VTH) and a fixed 600ms reset timeout after VCC recovery or MR deassertion. Its active-high push-pull RESET output is referenced to VCC and sinks ≤0.3V at 1.2mA load when asserted, while sourcing ≥0.8×VCC at 500µA when deasserted.

It includes an internally pulled-up MR input (10kΩ to VCC) with 1µs minimum pulse width support and 250ns MR-to-reset delay. Immune to VCC transients ≤40µs at 100mV overdrive, it operates across -40°C to +85°C with guaranteed reset validity down to VCC = +1.1V.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5 (lead-free, +T suffix), 2.9mm × 1.6mm footprint, 1.1mm height - compatible with standard high-density PCB assembly processes.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6855UK25D6+T, MAX6854UK25D6+T requires board-level redesign for RESET polarity and pullup, while TPS3837K25DBVR increases quiescent current significantly - making MAX6855UK25D6+T optimal for ultra-low-power, space-constrained medical and portable designs demanding active-high drive and nanoscale ICC.

Availability

MAX6855UK25D6+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, MP3 players, and PDAs requiring stable component supply with guaranteed long-term availability and lead-free compliance.

Supply support for MAX6855UK25D6+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 MAX685x family delivers nanopower supervision for battery-critical systems, emphasizing ultra-low ICC, guaranteed low-VCC operation, and minimal external component count in compact SOT23 packages.

FAQ

What is the exact reset threshold voltage of the MAX6855UK25D6+T?

The MAX6855UK25D6+T has a factory-trimmed reset threshold voltage of 2.500V with ±2.5% tolerance over -40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) and Electrical Characteristics, where "25" in the part number corresponds to 2.500V nominal VTH. The device guarantees reset assertion when VCC falls below this threshold and remains asserted until VCC exceeds it plus hysteresis (0.5% of VTH).

Does the MAX6855UK25D6+T include a watchdog timer function?

No, the MAX6855UK25D6+T does not include a watchdog timer. Per the Selector Guide and Pin Description, only MAX6864–MAX6869 variants feature WDI input and watchdog timeout functionality. The MAX6855UK25D6+T is a manual-reset-only supervisory circuit with active-high push-pull RESET, MR input, and fixed 600ms timeout - confirmed by its absence in the WDI column of the Selector Guide.

What is the reset timeout period for the MAX6855UK25D6+T, and how is it set?

The MAX6855UK25D6+T has a fixed 600ms minimum reset timeout period, indicated by the "D6" suffix in its part number. As specified in Table 4 (Reset Timeout Periods), D6 corresponds to 600ms (min), 900ms (typ), and 1200ms (max). This timeout is factory-programmed and non-adjustable - unlike MAX6861–MAX6863, which use the CT pin for selection. The timeout begins after VCC rises above VTH or MR deasserts.

How does the MR input behave on the MAX6855UK25D6+T?

The MR input on the MAX6855UK25D6+T is an active-low manual reset pin with an internal 10kΩ pullup to VCC. Driving MR low for ≥1µs asserts RESET high for the full timeout period (600ms min), even if MR returns high earlier. MR is immune to <200ns glitches and exhibits 250ns delay from MR low-to-high transition to RESET deassertion. Leaving MR unconnected defaults it to high via the internal pullup.

Is the MAX6855UK25D6+T pin-compatible with other devices in the MAX685x family?

The MAX6855UK25D6+T shares the same 5-pin SOT23-5 package and pinout (RESET, GND, MR, GND, VCC) with MAX6854, MAX6856, MAX6861–MAX6863, and MAX6864–MAX6869. However, pin compatibility does not imply functional interchangeability: MAX6855's active-high push-pull RESET differs electrically from MAX6854's open-drain or MAX6856's open-drain outputs, requiring schematic review before substitution.