Analog Devices Inc./Maxim Integrated MAX6855UK32D2+T

Overview

The MAX6855UK32D2+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, providing voltage monitoring, manual reset input (MR), and active-low push-pull reset output. It asserts reset when VCC drops below its factory-trimmed 3.2V threshold, MR is pulled low, or (in watchdog variants) WDI times out - with guaranteed reset validity down to VCC = +1.1V and ultra-low 170nA typical supply current. It is used in battery-powered glucose monitors and portable medical devices requiring reliable power-on reset and brownout protection.

For engineers reviewing the MAX6855UK32D2+T datasheet, MAX6855UK32D2+T pinout, MAX6855UK32D2+T application, or MAX6855UK32D2+T equivalent, key selection criteria include its 3.2V reset threshold, 40ms minimum reset timeout, -40°C to +85°C operating range, push-pull active-high reset output, and compatibility with low-voltage µP systems where supply current <200nA is critical.

Technical Context

This device belongs to the MAX6854–MAX6869 family of nanopower supervisory circuits. It implements a precision bandgap-based voltage monitor with ±2.5% threshold accuracy over temperature, a fixed 40ms minimum reset timeout (D2 option), and an internally pulled-up MR input with 10kΩ resistance and 250ns MR-to-reset delay.

Unlike watchdog-equipped variants (e.g., MAX6864–MAX6869), the MAX6855UK32D2+T lacks WDI functionality and CT select input. Its reset output is push-pull active-high - meaning RESET transitions high during fault conditions - and remains asserted for ≥40ms after VCC exceeds 3.2V and MR deasserts.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, surface-mount, lead-free (RoHS-compliant), 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 ADM6805-3ARTZ-RL7, the MAX6855UK32D2+T delivers 3.2V threshold precision, 40ms timing granularity, and nanopower operation - making it uniquely fit for next-generation portable medical devices where every nanoamp and millisecond matters.

Availability

The MAX6855UK32D2+T is available at Aetrix Electronics and suitable for glucose monitors, portable ECG devices, and wireless pulse oximeters requiring stable component supply across long production lifecycles and strict regulatory traceability.

Supply support for MAX6855UK32D2+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, mixed-signal, and power-management ICs for demanding industrial, medical, and communications applications.

The MAX6854–MAX6869 product line targets ultra-low-power supervisory needs in battery-operated medical and portable electronics, emphasizing sub-200nA operation, guaranteed low-VCC reset validity, and minimal external component count.

FAQ

What is the exact reset threshold voltage of the MAX6855UK32D2+T?

The MAX6855UK32D2+T has a factory-trimmed reset threshold of 3.200V, with ±2.5% tolerance over the full -40°C to +85°C temperature range. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "32" corresponds to 3.200V nominal. The MAX6855UK32D2+T maintains this accuracy without external calibration or trimming components.

Does the MAX6855UK32D2+T include a watchdog timer function?

No, the MAX6855UK32D2+T does not include a watchdog timer. It belongs to the MR-only subgroup (MAX6854/MAX6855/MAX6856) and lacks the WDI pin and associated watchdog circuitry. Watchdog capability is exclusive to MAX6864–MAX6869 variants. The MAX6855UK32D2+T provides only voltage monitoring and manual reset initiation.

What is the reset output configuration of the MAX6855UK32D2+T?

The MAX6855UK32D2+T features a push-pull active-high reset output. When VCC falls below 3.2V or MR is asserted, RESET goes high; it remains high for ≥40ms after VCC rises above threshold and MR is released. This eliminates need for external pullup resistors and simplifies interface to µPs with active-high reset inputs.

Can the MAX6855UK32D2+T operate reliably at VCC = 1.5V?

Yes, the MAX6855UK32D2+T is fully specified to operate down to VCC = 1.2V and guarantees valid reset assertion down to VCC = 1.1V. At 1.5V, all electrical characteristics - including 170nA supply current, 40ms timeout, and MR response - remain within datasheet limits, enabling use in deeply discharged lithium primary cells.

Is the MAX6855UK32D2+T pin-compatible with other devices in the MAX6854–MAX6869 family?

The MAX6855UK32D2+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, functional pin assignments differ: MAX6855 uses Pin 1 for active-high RESET, while MAX6854 uses Pin 1 for active-low RESET and MAX6864 uses Pin 1 for WDI - so direct substitution requires verification of reset polarity and feature set.