Analog Devices Inc./Maxim Integrated MAX6855UK45D3+T

Overview

MAX6855UK45D3+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring active-high push-pull reset output, 4.500V factory-trimmed reset threshold (±2.5%), 150ms minimum reset timeout, and manual reset input. It monitors VCC supply integrity for brownout detection and asserts reset during power-up, power-down, or MR activation in battery-powered portable systems.

For engineers reviewing the MAX6855UK45D3+T datasheet, MAX6855UK45D3+T pinout, MAX6855UK45D3+T application, or MAX6855UK45D3+T equivalent, this device supports low-voltage system supervision down to VCC = +1.1V, delivers ultra-low 170nA typical supply current, and integrates glitch-immune reset timing with 250ns MR-to-reset delay - critical for reliable boot sequencing in space-constrained, energy-sensitive designs.

Technical Context

The MAX6855UK45D3+T implements a precision bandgap-based voltage monitor with 2.5% threshold tolerance over -40°C to +85°C, coupled to a fixed 150ms (min) internal reset timeout timer. Its active-high push-pull RESET output is referenced to VCC and guarantees valid logic levels down to VCC = 1.1V, enabling robust reset assertion even during deep brownout conditions.

No watchdog timer or CT pin functionality is present - this variant is strictly a voltage-monitoring + manual reset IC with fixed D3 timeout and 4.500V threshold. The MR input includes an internal 10kΩ pullup and rejects <200ns glitches, supporting direct connection to momentary switches without external debounce.

Key Specifications

Pinout & Package

MAX6855UK45D3+T is housed in a lead-free 5-pin SOT23-5 package (2.9mm × 1.6mm × 1.1mm), optimized for high-density PCB layouts in portable electronics.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3837K33DBVR and MAX6315US31D3+, the MAX6855UK45D3+T uniquely combines 4.500V precision threshold, active-high push-pull output, and nanopower 170nA operation - making it optimal for next-generation 4.5V battery-supervised medical and industrial edge devices where reset polarity, accuracy, and energy efficiency are co-critical.

Availability

MAX6855UK45D3+T is available at Aetrix Electronics and suitable for portable medical devices, wearable health monitors, and industrial handheld terminals requiring stable component supply across extended product lifecycles.

Supply support for MAX6855UK45D3+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 MAX6855UK45D3+T belongs to the MAX6854–MAX6869 nanopower supervisory family, designed specifically for ultra-low-power, space-constrained battery-operated systems requiring precise voltage monitoring and deterministic reset behavior.

FAQ

What is the exact reset threshold voltage of the MAX6855UK45D3+T?

The MAX6855UK45D3+T has a factory-trimmed reset threshold voltage of +4.500V with ±2.5% tolerance over the full -40°C to +85°C operating temperature range. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix '45' corresponds to 4.500V nominal. The MAX6855UK45D3+T maintains this specification without external calibration.

Does the MAX6855UK45D3+T include a watchdog timer function?

No, the MAX6855UK45D3+T does not include a watchdog timer. It is a dedicated voltage supervisor with manual reset (MR) input and fixed 150ms reset timeout. Watchdog functionality is only present in MAX6864–MAX6869 variants (e.g., MAX6864UK45D3S+T), which include WDI pin and S/L timeout suffixes - absent in the MAX6855UK45D3+T ordering code.

What is the function of Pin 1 on the MAX6855UK45D3+T?

Pin 1 of the MAX6855UK45D3+T is the RESET output terminal, configured as an active-high push-pull driver. When asserted (during VCC undervoltage or MR activation), it drives high to VCC; when deasserted, it drives low. This eliminates the need for an external pullup resistor and provides rail-referenced logic compatibility with most microprocessors' active-high reset inputs.

Can the MAX6855UK45D3+T operate reliably below 1.2V?

The MAX6855UK45D3+T guarantees functional reset assertion down to VCC = +1.1V, as specified in the Electrical Characteristics table. While the recommended operating range starts at 1.2V, the device continues to assert RESET correctly at 1.1V with ISOURCE = 10µA, ensuring fail-safe behavior during extreme brownout conditions before complete power loss.

Is the MAX6855UK45D3+T pin-compatible with other MAX68xx supervisory ICs?

The MAX6855UK45D3+T shares the same 5-pin SOT23-5 package and pinout (RESET, GND, MR, GND, VCC) with MAX6854, MAX6856, MAX6861–MAX6863, and MAX6864–MAX6869 variants. However, output polarity (active-high vs. active-low), presence of CT or WDI pins, and internal timeout differ - so while physical mounting is identical, electrical compatibility requires verification of reset logic level and feature set.