Analog Devices Inc./Maxim Integrated MAX6423XS20+T

Overview

MAX6423XS20+T from Analog Devices is a low-power microprocessor supervisor IC in SC70-4 package, providing active-low open-drain reset output with 2.000V ±2.5% factory-trimmed reset threshold and capacitor-adjustable reset timeout (275µs to 5.75ms). It monitors VCC from 1.0V to 5.5V, draws only 1.6µA typical supply current, and guarantees valid reset operation down to VCC = 1V - used for reliable power-on reset in battery-powered embedded controllers.

For engineers reviewing the MAX6423XS20+T datasheet, MAX6423XS20+T pinout, MAX6423XS20+T application, or MAX6423XS20+T equivalent, key selection criteria include its SC70-4 footprint, open-drain logic compatibility with multiple supply rails, immunity to sub-50µs VCC transients, and guaranteed reset assertion at VCC < 2.000V across -40°C to +125°C.

Technical Context

The MAX6423XS20+T implements a precision voltage-detection architecture using laser-trimmed resistors to set its 2.000V reset threshold, with ±2.5% accuracy over full temperature range. Its reset timeout is generated by a 240nA internal ramp current charging an external capacitor (CSRT) to a 0.65V internal reference.

As an open-drain supervisor, it requires an external pullup resistor (10kΩ–100kΩ) to any rail up to 5.5V, enabling wired-OR reset configurations and logic-level translation - unlike push-pull variants, it does not drive high actively and cannot source current on RESET.

Key Specifications

Pinout & Package

MAX6423XS20+T is housed in a 4-pin SC70-4 package (package code X4+1), measuring 1.25mm × 0.85mm × 0.55mm, with 0.65mm lead pitch and RoHS-compliant lead-free finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6423US20+T, MAX6423XS20+T saves 35% board area with identical function; versus NCP302LSN20T1G, it provides design flexibility through adjustable timeout and open-drain output - critical for multi-voltage systems and fault-tolerant reset architectures.

Availability

MAX6423XS20+T is available at Aetrix Electronics and suitable for battery-powered instrumentation, automotive body electronics, and medical device controllers requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for MAX6423XS20+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

Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

The MAX6421–MAX6426 family delivers ultra-low-power, precision voltage supervision for resource-constrained embedded systems - designed specifically for applications demanding guaranteed reset behavior across wide temperature and supply ranges.

FAQ

What is the exact reset threshold voltage of MAX6423XS20+T and how is it trimmed?

The MAX6423XS20+T has a nominal reset threshold of 2.000V, with ±2.5% accuracy over -40°C to +125°C. This value is set during wafer fabrication using laser trimming of on-chip resistors, ensuring high initial accuracy without post-package calibration. The "20" suffix in MAX6423XS20+T explicitly denotes the 2.000V threshold variant per Analog Devices' standard ordering nomenclature.

Can MAX6423XS20+T drive a reset line directly without an external pullup resistor?

No - MAX6423XS20+T features an active-low open-drain RESET output and cannot drive high actively. An external pullup resistor (typically 10kΩ–100kΩ) to a logic-compatible voltage rail (0–5.5V) is mandatory to establish a valid logic-high state when reset is deasserted. Omitting the pullup results in floating RESET and undefined µP behavior.

How do I calculate the capacitor value needed for a 3.5ms reset timeout with MAX6423XS20+T?

Use the formula CSRT = (tRP − 275µs) / 2.735 × 10⁶, where tRP is in seconds. For 3.5ms: CSRT = (0.0035 − 0.000275) / 2,735,000 ≈ 1180pF. A standard 1200pF ceramic capacitor (X7R, low-leakage) meets this requirement and yields ~3.53ms timeout per datasheet characterization.

Is MAX6423XS20+T qualified for automotive applications?

While MAX6423XS20+T itself is not individually AEC-Q100 certified, it belongs to the MAX6421–MAX6426 family whose members (e.g., MAX6340UK31/V+T) are AEC-Q100 qualified. MAX6423XS20+T shares identical die, process (BiCMOS), and -40°C to +125°C operating range - commonly deployed in automotive body electronics where full qualification is not mandated, but robustness is required.

Does MAX6423XS20+T require special PCB layout considerations for the SRT pin?

Yes - the SRT pin connects to a precision 240nA ramp current source. Layout must minimize trace length, avoid nearby high-speed signals or high-voltage nodes, and prevent solder mask slivers or contamination that could introduce leakage >10nA. Use guard rings and clean prototype boards; scope probes on SRT will distort timeout accuracy.