Analog Devices Inc./Maxim Integrated MAX6401BS28-T

Overview

MAX6401BS28-T from Maxim Integrated is an ultra-low-power microprocessor supervisory circuit with active-high push-pull reset output, factory-trimmed 2.80V ±2.5% threshold (–40°C to +85°C), 100ms minimum reset timeout, and 500nA typical supply current at 3.0V. It monitors VCC in portable battery-powered systems and asserts RESET high during brownout or power-up sequencing.

For engineers reviewing the MAX6401BS28-T datasheet, MAX6401BS28-T pinout, MAX6401BS28-T application, or MAX6401BS28-T equivalent, key selection criteria include its 2.80V reset threshold accuracy, guaranteed reset validity down to VCC = 1.0V, immunity to sub-200ns VCC transients, and UCSP-4 package compatibility with space-constrained handheld designs.

Technical Context

The MAX6401BS28-T integrates a precision bandgap reference comparator and internal reset timer to generate a clean, glitch-immune active-high reset signal. Its reset assertion logic is inverted relative to MAX6400/MAX6402 - RESET goes high when VCC falls below 2.80V and remains high for ≥100ms after VCC recovers.

It features a manual reset input (MR) with internal 50kΩ pullup, TTL/CMOS-compatible thresholds, and 1µs minimum pulse width support. The device operates across VCC = 1.2V to 5.5V and guarantees correct output state down to VCC = 1.0V, enabling use in deep-battery-discharge scenarios.

Key Specifications

Pinout & Package

MAX6401BS28-T is housed in a 4-bump (2×2 mm) UCSP™ chip-scale package - footprint is 70% smaller than SC70 and optimized for ultra-compact portable PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6400BS28-T and TLV803EB28DBZR, the MAX6401BS28-T uniquely combines active-high push-pull drive, 500nA ultra-low ICC, and 2×2 mm UCSP-4 packaging - enabling direct µP interface and minimal board area in space- and power-constrained designs.

Availability

MAX6401BS28-T is available at Aetrix Electronics and suitable for portable/battery-powered equipment, cell phones, and MP3 players requiring stable component supply with guaranteed long-term availability and tape-and-reel delivery.

Supply support for MAX6401BS28-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, communications, and consumer applications.

The MAX6400–MAX6405 family was designed specifically for ultra-low-power microprocessor supervision in battery-critical portable electronics, emphasizing minimal ICC, factory-trimmed accuracy, and chip-scale packaging for size-sensitive designs.

FAQ

What is the exact reset threshold voltage of MAX6401BS28-T and how stable is it over temperature?

The MAX6401BS28-T has a nominal reset threshold of 2.80V, with ±2.5% accuracy guaranteed over the full –40°C to +85°C operating range. At +25°C, the threshold is 2.758V (min) to 2.842V (max); at temperature extremes, it shifts to 2.730V (min) to 2.870V (max). This stability ensures robust brownout detection without calibration across industrial environments.

Does MAX6401BS28-T require external components to function as a reset supervisor?

No, the MAX6401BS28-T requires no external components. Its precision bandgap reference, comparator, and 100ms reset timeout timer are fully integrated. Unlike discrete solutions, it eliminates the need for external resistors, capacitors, or voltage dividers - reducing BOM count and PCB area while improving reliability.

Can MAX6401BS28-T operate reliably when the supply voltage drops below 2.0V?

Yes, the MAX6401BS28-T guarantees correct reset output logic state down to VCC = 1.0V. Its internal circuitry remains functional and RESET remains asserted (high) even as VCC declines from 2.80V to 1.0V - making it suitable for deep-discharge battery monitoring in coin-cell and single-cell Li-ion applications.

What is the purpose of the MR pin on MAX6401BS28-T and how should it be used?

The MR (Manual Reset) pin on MAX6401BS28-T is an active-low input with an internal 50kΩ pullup to VCC. Pulling MR low asserts RESET high regardless of VCC level. It supports TTL/CMOS logic and requires only a momentary switch to GND - no external debouncing or pullup is needed, simplifying field-service or test-mode reset implementation.

How does the UCSP-4 package of MAX6401BS28-T compare to traditional SOT-23 in terms of board space and assembly?

The UCSP-4 package of MAX6401BS28-T measures 2mm × 2mm - 70% smaller than SC70 and significantly more compact than SOT-23. It uses bump-based interconnects instead of leads, requiring specialized reflow profiles and PCB pad design per Maxim's UCSP Reliability Notice. While not drop-in compatible with leaded packages, it enables highest-density portable PCB layouts when supported by assembly partners.