Analog Devices Inc./Maxim Integrated MAX6855UK37D3+T

Overview

The MAX6855UK37D3+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 3.700V reset threshold with 225ms 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. Used in battery-powered glucose monitors and portable medical devices requiring ultra-low quiescent current.

For engineers reviewing the MAX6855UK37D3+T datasheet, MAX6855UK37D3+T pinout, MAX6855UK37D3+T application, or MAX6855UK37D3+T equivalent, key selection criteria include its 170nA typical supply current, 3.700V ±2.5% reset threshold, 225ms reset timeout, MR input with 10kΩ internal pullup, and guaranteed reset validity at VCC ≥ 1.1V - all critical for low-power embedded system reliability.

Technical Context

The MAX6855UK37D3+T implements a precision voltage monitor with hysteresis (0.5% of VTH) and a fixed-reset-timeout generator. Its reset assertion logic responds to VCC falling below 3.700V, MR low pulse ≥1µs, or both - with reset deassertion delayed by a guaranteed minimum 225ms after VCC rises above threshold and MR releases.

It uses BiCMOS process technology (2848 transistors) and features immunity to short VCC transients (e.g., ≤40µs for 100mV overdrive), no external components required, and operates across –40°C to +85°C. Unlike watchdog-equipped variants (e.g., MAX6864–MAX6869), this part omits WDI functionality and CT select input, confirming its role as a dedicated manual-reset supervisory IC.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount. Compact footprint (2.9mm × 1.6mm × 1.1mm) suitable for space-constrained portable designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3837K33DBVR and MAX6315US37D3+, the MAX6855UK37D3+T uniquely delivers active-high push-pull reset, 170nA supply current, and integrated MR - enabling direct µP interface, decade-long battery life, and field-serviceable reset in compact medical and industrial devices.

Availability

MAX6855UK37D3+T is available at Aetrix Electronics and suitable for glucose monitoring systems, patient vital sign monitors, industrial handheld scanners, and low-power IoT edge sensors requiring stable component supply across extended product lifecycles.

Supply support for MAX6855UK37D3+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 communications markets.

The MAX6854–MAX6869 family delivers nanopower supervisory functions for battery-critical systems - engineered specifically for ultra-low-IQ voltage monitoring, manual reset, and deterministic reset timing in portable medical and instrumentation equipment.

FAQ

What is the exact reset threshold voltage of the MAX6855UK37D3+T?

The MAX6855UK37D3+T has a factory-trimmed reset threshold of 3.700V, with tolerance of ±2.5% (3.608V to 3.793V) over –40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "37" corresponds to 3.700V nominal. The MAX6855UK37D3+T maintains this specification without external calibration.

Does the MAX6855UK37D3+T include a watchdog timer function?

No, the MAX6855UK37D3+T does not include a watchdog timer. Per the Selector Guide and Pin Description sections, only MAX6864–MAX6869 variants feature WDI input; the MAX6855UK37D3+T belongs to the MR-only subgroup (MAX6854/MAX6855/MAX6856). Its functional block diagram confirms absence of watchdog circuitry - it provides only VCC monitoring and manual reset.

What is the reset output configuration of the MAX6855UK37D3+T?

The MAX6855UK37D3+T features an active-high push-pull reset output (pin 1), as specified in the MAX6855/MAX6856 Pin Description table. When reset is asserted, RESET drives high; when deasserted, it drives low. This eliminates need for external pullup resistors and directly interfaces with µPs requiring active-high reset signals - unlike open-drain or active-low variants in the same family.

What is the minimum reset timeout period for the MAX6855UK37D3+T?

The MAX6855UK37D3+T has a minimum reset timeout period of 225ms, corresponding to the "D3" suffix per Table 4 (Reset Timeout Periods). This is the guaranteed minimum duration RESET remains asserted after VCC exceeds 3.700V and MR is released. Typical and maximum values are 225ms and 300ms respectively, validated across temperature and supply voltage ranges.

Is the MAX6855UK37D3+T pin-compatible with other parts in the MAX6854–MAX6869 family?

The MAX6855UK37D3+T shares the same 5-pin SOT23-5 package and pinout (RESET, GND, MR, GND, VCC) with MAX6854 and MAX6856, but differs from MAX6861–MAX6869 (which use CT pin) and MAX6864–MAX6869 (which use WDI pin). Pin compatibility is limited to the MR-only, non-watchdog, non-CT subgroup - verified in the Pin Configurations diagram and Selector Guide.