Analog Devices Inc./Maxim Integrated MAX6401BS22+

Overview

The MAX6401BS22+ from Maxim Integrated is an ultra-low-power microprocessor supervisory circuit with active-high push-pull reset output, factory-trimmed 2.20V reset threshold (±2.5% over –40°C to +85°C), 100ms minimum reset timeout, and 500nA typical supply current at 3.0V. It monitors VCC down to 1.0V and supports manual reset input for brownout and power-up supervision in battery-powered systems.

For engineers reviewing the MAX6401BS22+ datasheet, MAX6401BS22+ pinout, MAX6401BS22+ application, or MAX6401BS22+ equivalent, this device is selected for portable equipment requiring guaranteed reset assertion during low-VCC conditions, immunity to fast transients, and minimal board space via its 2×2 mm UCSP-4 package.

Technical Context

The MAX6401BS22+ uses a precision bandgap reference comparator to monitor VCC against a fixed 2.20V threshold. Its internal timer ensures RESET remains high for ≥100ms after VCC rises above VTH, and it guarantees valid reset logic state down to VCC = 1.0V.

It features a manual reset (MR) input with 50kΩ internal pullup, TTL/CMOS-compatible logic levels, and 1µs minimum pulse width requirement. The active-high push-pull output drives high with ≥0.8×VCC (at ISOURCE = 500µA, VCC ≥ 2.1V) and low with ≤0.4V (at ISINK = 3.2mA, VCC ≥ 4.5V).

Key Specifications

Pinout & Package

Package: 4-bump UCSP (2mm × 2mm, 0.5mm pitch), lead-free, RoHS-compliant chip-scale package optimized for ultra-compact portable designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6401BS22+, the MAX6401BS23+ offers a 120mV higher threshold for tighter brownout control without changing layout or firmware, while the TPS3808G12DBVR trades ultra-low ICC for larger footprint and incompatible output polarity-requiring redesign of reset signal routing and µP configuration.

Availability

MAX6401BS22+ is available at Aetrix Electronics and suitable for portable medical devices, battery-powered IoT sensors, and handheld consumer electronics requiring stable component supply with long-term manufacturability and consistent parametric performance.

Supply support for MAX6401BS22+ 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 U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, communications, and consumer markets.

The MAX6400–MAX6405 family was designed specifically for ultra-low-power microprocessor supervision in space-constrained, battery-operated equipment-emphasizing sub-µA quiescent current, factory-trimmed thresholds, and chip-scale packaging.

FAQ

What is the exact reset threshold voltage of the MAX6401BS22+ and how accurate is it over temperature?

The MAX6401BS22+ has a factory-trimmed nominal reset threshold of 2.20V, with ±2.5% accuracy guaranteed over the full operating temperature range of –40°C to +85°C. At +25°C, the threshold is specified between 2.167V (min) and 2.233V (max). This tight tolerance eliminates the need for external calibration components and ensures reliable brownout detection across environmental conditions. The MAX6401BS22+ achieves this using a precision bandgap reference comparator architecture.

Does the MAX6401BS22+ require external components to function as a complete reset supervisor?

No, the MAX6401BS22+ requires no external components for basic operation. It integrates a precision voltage reference, comparator, timer, and 50kΩ internal pullup on the MR pin. Only VCC, GND, RESET, and MR connections are needed. The active-high push-pull output eliminates the need for an external pullup resistor, and the 500nA supply current means no decoupling capacitor is mandatory-though a 0.1µF ceramic cap on VCC is recommended for noise immunity in noisy environments. The MAX6401BS22+ is designed for minimal BOM count and PCB area.

How does the manual reset (MR) input behave on the MAX6401BS22+?

The MR input on the MAX6401BS22+ is active-low with an internal 50kΩ pullup to VCC. When MR is pulled to GND, RESET immediately goes high and stays high for the full reset timeout period (≥100ms) after MR returns high. If MR remains low, RESET stays high continuously. The input accepts TTL- and CMOS-compatible logic levels and rejects glitches shorter than 100ns. No external debouncing is required-connecting a momentary switch from MR to GND provides fully functional manual reset. This behavior is confirmed in the MAX6401BS22+ timing diagram and electrical specifications.

Can the MAX6401BS22+ operate reliably at VCC voltages below 2.2V?

Yes, the MAX6401BS22+ is guaranteed to maintain correct RESET logic state down to VCC = 1.0V. While the reset function activates when VCC falls below 2.20V, the internal circuitry-including comparator, timer, and output driver-remains fully functional and predictable at supply voltages as low as 1.2V (–40°C to +85°C) and 1.0V (at +25°C). This ensures deterministic behavior during deep brownout or battery exhaustion, making the MAX6401BS22+ suitable for applications where supply collapse must be cleanly managed before shutdown.

What package type and dimensions does the MAX6401BS22+ use, and is it RoHS-compliant?

The MAX6401BS22+ uses a 4-bump UCSP (Ultra Compact Silicon Package) measuring 2.0mm × 2.0mm with 0.5mm bump pitch. It is a lead-free, RoHS-compliant chip-scale package with solder bumps replacing traditional leads. This package delivers a 70% size reduction versus SC70 and enables ultra-dense PCB layouts. The UCSP construction requires careful attention to PCB pad design, solder paste volume, and reflow profile-but no special handling or underfill is mandated for standard assembly. The MAX6401BS22+ top mark is ABM per Maxim's marking code table.