Analog Devices Inc./Maxim Integrated MAX6404BS44

Overview

MAX6404BS44 from Maxim Integrated is an ultra-low-power microprocessor supervisory circuit with active-high push-pull reset output, factory-trimmed 4.38V threshold (±2.5% over –40°C to +85°C), 100ms minimum reset timeout, and 500nA typical supply current at 3.0V. It monitors regulated system voltages in portable battery-powered equipment where reliable power-on reset and brownout detection are critical.

For engineers reviewing the MAX6404BS44 datasheet, MAX6404BS44 pinout, MAX6404BS44 application, or MAX6404BS44 equivalent, key selection considerations include its 4.38V trip point, VCC-down-to-1V guaranteed reset validity, manual reset input with internal 50kΩ pullup, immunity to sub-200ns VCC transients, and UCSP-4 package compatibility with space-constrained handheld designs.

Technical Context

The MAX6404BS44 uses a precision bandgap reference comparator to detect when VCC falls below its 4.38V threshold, asserting an active-high RESET signal. Its internal timer guarantees a minimum 100ms reset pulse after VCC rises above threshold, and it remains valid down to VCC = 1.0V - enabling operation during deep brownout conditions.

It features a dedicated manual reset (MR) input with 1µs minimum pulse width, 100ns glitch rejection, and internal 50kΩ pullup; MR assertion forces RESET high for the full timeout period regardless of VCC level. The device is immune to fast negative-going VCC transients up to 200ns at 100mV overdrive.

Key Specifications

Pinout & Package

MAX6404BS44 is housed in a 4-bump, 2×2 mm chip-scale package (UCSP-4), optimized for minimal PCB footprint in space-constrained portable applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6404BS44, MAX6404BS43-T offers a 80mV lower trip point for earlier brownout response within the same family, while TPS3808G33DBVR provides a TI-sourced alternative with different threshold, output polarity, and higher quiescent current - making it suitable only where 3.3V monitoring and SOT-23 packaging are prioritized over ultra-low power and 4.38V precision.

Availability

MAX6404BS44 is available at Aetrix Electronics and suitable for portable medical monitors, industrial handheld terminals, wearable fitness trackers, and smart remote controls requiring stable component supply, long-term lifecycle support, and consistent UCSP-4 packaging.

Supply support for MAX6404BS44 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 equipment, emphasizing minimal footprint, nanoscale quiescent current, and factory-trimmed voltage thresholds to eliminate calibration overhead.

FAQ

What is the exact reset threshold voltage of MAX6404BS44 and how stable is it over temperature?

The MAX6404BS44 has a nominal reset threshold of 4.38V, with ±2.5% accuracy guaranteed over the full –40°C to +85°C operating range. At +25°C, the tolerance is tighter at ±1.5%. This stability is achieved via factory laser trimming of an internal bandgap reference comparator, ensuring consistent brownout detection without external components or calibration.

Does MAX6404BS44 require external components to function as a supervisory circuit?

No, MAX6404BS44 requires no external components to operate. Its precision bandgap reference, comparator, and timer are fully integrated. The manual reset (MR) input includes a built-in 50kΩ pullup resistor, and the active-high push-pull RESET output drives directly into a microprocessor's reset pin without needing a pullup or pulldown network - reducing BOM count and PCB area.

Can MAX6404BS44 operate reliably when the supply voltage drops below 2.0V?

Yes, MAX6404BS44 is guaranteed to assert a valid reset signal down to VCC = 1.0V. Its internal circuitry remains functional and maintains correct RESET logic state (high during undervoltage) even at 1.0V, enabling robust operation during deep brownout conditions common in fading battery scenarios - a key differentiator versus many competing supervisors rated only to 1.2V or higher.

What is the purpose of the MR input on MAX6404BS44 and how should it be used?

The MR input on MAX6404BS44 is an active-low manual reset pin that forces the RESET output high for the full timeout period (≥100ms) when pulled low. It features internal 50kΩ pullup, so it can be left unconnected if unused. For implementation, connect a normally open momentary switch between MR and GND - no external debounce circuitry is required due to built-in 100ns glitch rejection and 1µs minimum pulse width specification.

Is MAX6404BS44 pin-compatible with other devices in the MAX6400–MAX6405 family?

Yes, MAX6404BS44 shares identical UCSP-4 pinout and terminal functions with all members of the MAX6400–MAX6405 family: GND (A1), RESET (B1), MR (B2), and VCC (A2). This allows direct substitution within the same package variant - for example, replacing MAX6404BS44 with MAX6404BS43-T requires no PCB changes, only firmware validation of the 4.30V vs 4.38V threshold impact on system behavior.