Analog Devices Inc./Maxim Integrated MAX6855UK33D6+T

Overview

The MAX6855UK33D6+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 3.3V reset threshold (±2.5%). It provides 1200ms minimum reset timeout, ultra-low 170nA typical supply current, and guaranteed reset validity down to VCC = +1.1V - designed for reliable power-on reset and brownout protection in battery-powered medical and portable electronics.

For engineers reviewing the MAX6855UK33D6+T datasheet, MAX6855UK33D6+T pinout, MAX6855UK33D6+T application, or MAX6855UK33D6+T equivalent, key selection criteria include its fixed 3.3V threshold, 1200ms timeout, active-high push-pull RESET logic, MR-driven reset assertion, and immunity to sub-40µs VCC transients at 100mV overdrive - all critical for low-power µP systems requiring deterministic startup behavior.

Technical Context

This device implements a precision voltage monitor with hysteresis (0.5% of VTH), a digital reset timeout timer, and CMOS-compatible MR input with 10kΩ internal pullup. The active-high push-pull RESET output drives directly to VCC (VOH ≥ 0.8×VCC at ISOURCE = 500µA) and sinks to ≤0.3V (VOL ≤ 0.3V at ISINK = 1.2mA) when asserted, eliminating external pullup components.

Unlike watchdog-equipped variants (e.g., MAX6864–MAX6869), the MAX6855UK33D6+T lacks WDI and CT pins - it is a dedicated voltage-monitoring supervisor with no watchdog or timeout-select functionality. Its timing behavior is fully defined by VTH, tRP = 600–1200ms (D6 option), and tRD = 40µs VCC-to-reset delay.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free (RoHS-compliant), footprint-compatible with industry-standard 5-pin SOT23 devices.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3837K33DBVR and MAX6315US33D3+, the MAX6855UK33D6+T uniquely delivers active-high push-pull RESET, 1200ms timeout, and 170nA ICC in the same SOT23-5 package - making it optimal for long-life, active-high-reset µP systems where minimal BOM count and ultra-low leakage are essential.

Availability

MAX6855UK33D6+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered IoT sensors, wearable health trackers, and industrial handheld terminals requiring stable component supply across extended production lifecycles.

Supply support for MAX6855UK33D6+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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, medical, and communications applications.

The MAX6854–MAX6869 family was designed specifically for nanopower microprocessor supervision in battery-critical systems - delivering precision voltage monitoring, manual reset, and configurable timing in minimal-footprint packages.

FAQ

What is the exact reset threshold voltage of the MAX6855UK33D6+T?

The MAX6855UK33D6+T has a factory-trimmed reset threshold of 3.3V with ±2.5% tolerance (3.2175V to 3.3825V). This value is confirmed in Table 2 of the datasheet under suffix "33", and applies across the full operating temperature range of -40°C to +85°C. The threshold is referenced to the VCC supply being monitored.

Does the MAX6855UK33D6+T include a watchdog timer function?

No, the MAX6855UK33D6+T does not include a watchdog timer. It belongs to the MAX6854/MAX6855/MAX6856 subgroup, which supports only voltage monitoring and manual reset. Watchdog functionality is exclusive to MAX6864–MAX6869 variants (e.g., MAX6864UK33D6S+T), identifiable by the "S" or "L" suffix in the ordering code.

What does the "D6" in MAX6855UK33D6+T indicate?

The "D6" suffix specifies the reset timeout period option: 600ms (min), 900ms (typ), 1200ms (max). This is defined in Table 4 of the datasheet. The D6 option ensures the reset signal remains asserted long enough for slow-starting peripherals - such as ADCs or RF modules - to stabilize before µP execution resumes.

Is the MAX6855UK33D6+T pin-compatible with other SOT23-5 supervisors?

The MAX6855UK33D6+T uses Pins 1 (RESET), 2 (GND), 3 (MR), 4 (GND), and 5 (VCC) in SOT23-5. While physically compatible with standard 5-pin SOT23 footprints, it is not functionally pin-compatible with active-low or open-drain supervisors (e.g., MAX6856) due to differing RESET polarity and pin assignments - always verify pin functions against the specific variant's pin description table.

What is the maximum VCC transient duration the MAX6855UK33D6+T can ignore at 100mV overdrive?

Per the "Maximum VCC Transient Duration vs. Reset Threshold Overdrive" graph (Figure MAX684 toc05), the MAX6855UK33D6+T typically ignores VCC transients ≤40µs when the overdrive is 100mV. This immunity prevents false resets caused by switching noise from DC/DC converters or motor drivers in compact portable designs.