Analog Devices Inc./Maxim Integrated MAX6400BS29

Overview

MAX6400BS29 from Maxim Integrated is an ultra-low-power microprocessor supervisory circuit designed to monitor VCC supply voltage and assert a reset signal when voltage falls below 2.93V (±2.5% over -40°C to +85°C). It features active-low push-pull RESET output, manual reset input (MR), factory-set 100ms minimum reset timeout, and guaranteed operation down to VCC = 1.0V. It is used in battery-powered portable electronics such as MP3 players and PDAs for reliable power-on and brownout reset control.

For engineers reviewing the MAX6400BS29 datasheet, MAX6400BS29 pinout, MAX6400BS29 application, or MAX6400BS29 equivalent, key selection criteria include its 2.93V threshold accuracy, 500nA typical supply current, UCSP-4 package footprint, and compatibility with systems requiring VCC monitoring from 1.2V to 5.5V with immunity to short transients.

Technical Context

The MAX6400BS29 integrates a precision bandgap reference comparator trimmed to 2.93V nominal threshold, with ±2.5% accuracy across -40°C to +85°C and 40ppm/°C tempco. Its internal timer ensures RESET remains asserted for ≥100ms after VCC rises above threshold, and it ignores fast VCC transients up to 200µs at 100mV overdrive.

It supports manual reset via MR pin with internal 50kΩ pullup, 1µs minimum pulse width, and 100ns glitch rejection. The push-pull RESET output sinks ≥1.6mA at VCC ≥ 2.1V (VOL ≤ 0.3V) and sources ≥500µA at VCC = 3.2V (VOH ≥ 0.8×VCC) when deasserted.

Key Specifications

Pinout & Package

MAX6400BS29 is housed in a 4-bump, 2×2 mm chip-scale package (UCSP-4), offering 70% smaller footprint than SC70. The package uses solder bumps directly attached to PCB pads, requiring controlled assembly per Maxim's UCSP reliability guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6400BS29, MAX6326UR29 trades ultra-low current and minimal footprint for easier assembly, while TPS3123QDBVRQ1 adds automotive qualification at the cost of higher quiescent current and open-drain interface complexity-neither offers pin-to-pin compatibility.

Availability

MAX6400BS29 is available at Aetrix Electronics and suitable for portable audio devices, handheld medical monitors, wearable fitness trackers, and smart remote controls requiring stable component supply and long-term production continuity.

Supply support for MAX6400BS29 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, with emphasis on high-reliability, low-power solutions.

The MAX6400–MAX6405 family was developed specifically for ultra-low-power microprocessor supervision in space- and energy-constrained portable electronics, featuring factory-trimmed thresholds and chip-scale packaging.

FAQ

What is the exact reset threshold voltage of the MAX6400BS29 and how accurate is it over temperature?

The MAX6400BS29 has a nominal reset threshold of 2.93V, with ±2.5% accuracy guaranteed over the full operating temperature range of –40°C to +85°C. At +25°C, the tolerance tightens to ±1.5%. This precision eliminates the need for external trimming resistors and ensures consistent brownout detection across environmental conditions in the MAX6400BS29.

Does the MAX6400BS29 require any external components to operate?

No-the MAX6400BS29 requires no external components for basic operation. Its internal bandgap reference, precision comparator, and 50kΩ MR pullup resistor are fully integrated. Only VCC, GND, RESET, and MR connections are needed on the PCB. This integration reduces BOM cost and layout complexity in the MAX6400BS29 design.

What is the supply current of the MAX6400BS29 and why does it matter for battery-powered systems?

The MAX6400BS29 draws just 500nA typical supply current at +25°C and VCC = 3.0V-among the lowest in its class. In a device powered by a 220mAh coin cell, this enables over 10 years of shelf life before reset functionality degrades. That ultra-low current is central to the MAX6400BS29's value in portable and wearable applications.

How does the MAX6400BS29 handle short voltage transients on the VCC line?

The MAX6400BS29 rejects VCC transients up to 200µs in duration when the overdrive (VTH – VCC) is 100mV, per its Typical Operating Characteristics graph. This built-in immunity prevents false resets caused by switching regulator noise or ESD-induced dips-ensuring robust operation without external filtering in the MAX6400BS29 implementation.

What package type does the MAX6400BS29 use and what are its assembly considerations?

The MAX6400BS29 uses a 4-bump, 2×2 mm UCSP (chip-scale package), which is 70% smaller than SC70. Assembly requires adherence to Maxim's UCSP reliability guidelines-including controlled reflow profile, FR4 board material selection, and avoidance of mechanical stress on solder bumps-because the MAX6400BS29 relies on direct die-to-PCB interconnect rather than leadframe-based packaging.