Analog Devices Inc./Maxim Integrated MAX6423XS29+

Overview

MAX6423XS29+ from Maxim Integrated is a low-power microprocessor supervisor IC with open-drain active-low reset output, 2.925V nominal reset threshold (±2.5% over temperature), capacitor-adjustable reset timeout (275µs to 5.75ms), and guaranteed operation down to VCC = 1V. It monitors supply voltage in battery-powered embedded controllers and portable equipment requiring precise brownout protection.

For engineers reviewing the MAX6423XS29+ datasheet, MAX6423XS29+ pinout, MAX6423XS29+ application, or MAX6423XS29+ equivalent, key selection criteria include its SC70-4 package, 1.6µA typical quiescent current, open-drain RESET compatibility with multiple logic supplies, immunity to short VCC transients, and factory-laser-trimmed reset threshold accuracy.

Technical Context

The MAX6423XS29+ implements a precision voltage-detection architecture using laser-trimmed resistors to set its 2.925V reset threshold, with ±2.5% tolerance across –40°C to +125°C. Its reset assertion is triggered by VCC falling below this threshold, and deassertion is delayed by an externally adjustable timeout determined by an internal 240nA ramp current charging a capacitor on the SRT pin.

As an open-drain device, MAX6423XS29+ requires an external pullup resistor (10kΩ–100kΩ) to any supply up to 5.5V, enabling flexible logic-level interfacing and wired-OR reset capability. It guarantees valid RESET output down to VCC = 1V but does not support valid logic at VCC = 0 without external pulldown.

Key Specifications

Pinout & Package

MAX6423XS29+ is housed in a 4-pin SC70-4 package (package code X4+1, outline 21-0098), measuring 2.0mm × 2.1mm × 0.95mm, with wettable flanks for automated optical inspection. Pin 1 is marked with a dot; pin numbering follows standard SC70 top-view orientation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NCP302LSN29T1G and TPS3808G12QDBVRQ1, MAX6423XS29+ uniquely combines factory-trimmed accuracy, capacitor-adjustable timeout, open-drain output, and sub-2µA quiescent current in a 4-pin SC70 - making it optimal for portable, battery-sensitive, and multi-rail systems where timing flexibility and logic-level independence are essential.

Availability

MAX6423XS29+ is available at Aetrix Electronics and suitable for battery-powered portable instruments, automotive body control modules, industrial smart sensors, and set-top box power management requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX6423XS29+ 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 solutions for industrial, automotive, communications, and consumer markets.

The MAX6421–MAX6426 family was designed specifically for ultra-low-power microprocessor supervision in space- and energy-constrained applications, emphasizing precision threshold accuracy, flexible reset timing, and robust transient immunity.

FAQ

What is the exact reset threshold voltage of MAX6423XS29+ and how stable is it over temperature?

The MAX6423XS29+ has a nominal reset threshold of 2.925V, with ±2.5% accuracy guaranteed over the full operating temperature range of –40°C to +125°C. This stability is achieved via factory laser trimming of internal resistors and is documented in the Electrical Characteristics table under "VCC Reset Threshold Accuracy" with test conditions explicitly covering TA = –40°C to +125°C.

Does MAX6423XS29+ support operation at VCC = 1.0V, and what happens to RESET functionality at that level?

Yes, MAX6423XS29+ guarantees valid RESET output down to VCC = 1.0V. At this voltage, the open-drain RESET remains functional with VOL ≤ 0.3V at ISINK = 500µA. However, below 1.0V, sink capability declines sharply; for applications requiring valid logic down to 0V, a 100kΩ pulldown resistor on RESET is recommended - a solution explicitly validated in the datasheet's Applications Information section.

How do I calculate the reset timeout capacitor value for a desired delay with MAX6423XS29+?

Use the formula CSRT = (tRP – 275µs) / 2.73×10⁶, where tRP is the desired timeout in seconds and CSRT is in farads. For example, a 4.375ms timeout requires CSRT = (0.004375 – 0.000275) / 2.73×10⁶ = 1500pF. The datasheet specifies ceramic capacitors (<10nA leakage) for best accuracy, and Figure 1 confirms this relationship with measured data across temperature.

Can MAX6423XS29+ be used in a wired-OR reset configuration, and what design considerations apply?

Yes, MAX6423XS29+ supports wired-OR reset via its open-drain RESET output. Connect additional open-drain reset sources (e.g., watchdog ICs or fault monitors) directly to the same RESET net with a shared pullup. The datasheet's Figure 2 shows this topology and notes that external signals can hold the system in reset, though they do not extend the timeout period - only the MAX6423XS29+'s internal timer controls deassertion timing.

What package type and footprint does MAX6423XS29+ use, and where can I find land pattern details?

MAX6423XS29+ uses the 4-pin SC70-4 package (outline 21-0098, land pattern 90-0187). Official footprint and solder-paste stencil data are published by Maxim Integrated at maximintegrated.com/packages. The "+" suffix denotes lead(Pb)-free construction, and the package features wettable flanks for automated optical inspection - both confirmed in the Package Information section on page 9 of the datasheet.