Analog Devices Inc./Maxim Integrated MAX6855UK45D5+T

Overview

The MAX6855UK45D5+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 4.500V reset threshold with 300ms minimum reset timeout. It monitors VCC supply integrity, asserts reset during brownout or manual trigger, and guarantees valid reset operation down to VCC = +1.1V. It is designed for low-power portable systems where supply stability and deterministic reset timing are critical.

For engineers reviewing the MAX6855UK45D5+T datasheet, MAX6855UK45D5+T pinout, MAX6855UK45D5+T application, or MAX6855UK45D5+T equivalent, this page delivers verified functional identity, exact pin roles, confirmed electrical behavior across temperature, real-world timing constraints (tRP = 300ms min, tMRD = 250ns), and validated alternatives for battery-powered medical and consumer electronics design.

Technical Context

This device implements a precision voltage monitor with ±2.5% reset threshold accuracy over -40°C to +85°C, coupled with a fixed 300ms minimum reset timeout period after VCC recovery or MR deassertion. Its active-high push-pull RESET output drives directly to VCC and maintains logic-high state during reset assertion - unlike open-drain or active-low variants in the family.

The internal 10kΩ MR pullup ensures robust manual reset initiation without external components, and immunity to VCC transients ≤40µs at 100mV overdrive enables reliable operation in noisy power environments. No watchdog timer or CT select input is present - confirming MAX6855UK45D5+T as a dedicated voltage-monitoring + MR supervisory IC without programmable timeout or watchdog functionality.

Key Specifications

Pinout & Package

MAX6855UK45D5+T uses a standard 5-pin SOT23-5 package (JEDEC MO-178AA), with pin 1 marked by a dot or bevel. Pin functions are fully defined per Maxim's official pin description table for MAX6855.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3837K33DBVR and MAX6315US31D3+, the MAX6855UK45D5+T uniquely combines 4.500V precision threshold, 300ms extended timeout, active-high push-pull output, and integrated MR pullup - making it optimal for 4.5V battery-backed medical and industrial systems demanding fail-safe reset assurance.

Availability

MAX6855UK45D5+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered consumer electronics, and industrial handheld terminals requiring stable component supply with guaranteed long-term availability and lead-free compliance.

Supply support for MAX6855UK45D5+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 MAX6855UK45D5+T belongs to the MAX6854–MAX6869 nanopower µP supervisory family, engineered specifically for ultra-low-current battery-powered systems requiring precise voltage monitoring, deterministic reset timing, and minimal external components.

FAQ

What is the exact reset threshold voltage of the MAX6855UK45D5+T?

The MAX6855UK45D5+T has a factory-trimmed reset threshold voltage of +4.500V, with guaranteed tolerance of ±2.5% 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 device asserts reset when VCC falls below this threshold and holds reset asserted for the full 300ms timeout after VCC recovers above it.

Does the MAX6855UK45D5+T include a watchdog timer function?

No, the MAX6855UK45D5+T does not include a watchdog timer. Per the Selector Guide and Pin Description tables, MAX6855 is explicitly listed without WDI (Watchdog Input) functionality. Watchdog capability is only present in MAX6864–MAX6869 variants (e.g., MAX6864UK16D3S). The MAX6855UK45D5+T provides only VCC monitoring, manual reset (MR), and fixed 300ms reset timeout - consistent with its designation as a core supervisory circuit without system-level fault detection.

What is the reset output type and drive capability of the MAX6855UK45D5+T?

The MAX6855UK45D5+T features an active-high push-pull RESET output. When asserted, RESET drives high to VCC; when deasserted, it drives low to GND. Electrical characteristics confirm VOH ≥ 0.8 × VCC (with ISOURCE = 500µA) and VOL ≤ 0.3V (with ISINK = 1.2mA), enabling direct interface to µP reset inputs requiring active-high logic without external components.

Can the MAX6855UK45D5+T operate reliably at VCC = 1.2V?

Yes, the MAX6855UK45D5+T is fully specified to operate at VCC = 1.2V, as stated in the Absolute Maximum Ratings and Electrical Characteristics tables. Its reset output remains valid down to VCC = +1.1V, and supply current is characterized at 1.2V (190nA typical). This ensures robust brownout detection and reset assertion even during deep supply droop - a key requirement for battery-powered systems nearing end-of-life.

Is the MAX6855UK45D5+T pin-compatible with other devices in the MAX6854–MAX6869 family?

The MAX6855UK45D5+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, pin compatibility does not imply functional equivalence: MAX6855 provides active-high push-pull RESET, whereas MAX6854 offers active-low push-pull and MAX6856 offers active-low open-drain. PCB layout reuse is possible only if the target variant matches the same output polarity and feature set.