Analog Devices Inc./Maxim Integrated MAX6423XS25+

Overview

MAX6423XS25+ from Maxim Integrated is a low-power microprocessor supervisor IC with open-drain active-low reset output, 2.5V factory-trimmed reset threshold (±1.5% at +25°C), capacitor-adjustable reset timeout (275µs base + 2.73s/F × CSRT), and guaranteed operation down to VCC = 1V. It monitors system supply voltage in portable, battery-powered, and automotive electronics to prevent code-execution errors during power-up, brownout, or power-down.

For engineers reviewing the MAX6423XS25+ datasheet, MAX6423XS25+ pinout, MAX6423XS25+ application, or MAX6423XS25+ equivalent, key selection criteria include its SC70-4 package, 1.6µA typical quiescent current, open-drain RESET compatibility with multiple logic supplies (0–5.5V), and immunity to short VCC transients ≤50µs when overdriven by 100mV.

Technical Context

The MAX6423XS25+ implements a precision voltage-monitoring circuit with laser-trimmed resistors to set its 2.5V reset threshold, coupled with a 240nA internal ramp current source that charges an external capacitor (CSRT) to generate the reset timeout delay. Its open-drain RESET output requires an external pullup resistor and remains asserted low until the SRT capacitor voltage reaches 0.65V after VCC recovers above threshold.

It operates across –40°C to +125°C, maintains reset validity down to VCC = 1V, and features hysteresis of 4×VTH (10mV at 2.5V), ensuring noise immunity without false triggering. The device is immune to negative-going VCC transients ≤50µs when the overdrive is 100mV below VTH, as verified by transient duration vs. overdrive characterization.

Key Specifications

Pinout & Package

MAX6423XS25+ is housed in a 4-pin SC70-4 package (2.0mm × 2.1mm, 0.5mm pitch), optimized for space-constrained portable and embedded designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6423US25+, the SC70 variant offers superior board-area efficiency; versus TLV803EB25DBZR, MAX6423XS25+ delivers design flexibility via programmable timeout and open-drain interoperability-critical for multi-rail and fault-tolerant systems.

Availability

MAX6423XS25+ is available at Aetrix Electronics and suitable for battery-powered medical sensors, automotive body control modules, and industrial handheld terminals requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6423XS25+ 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 demanding industrial, automotive, and computing applications.

The MAX6421–MAX6426 family delivers ultra-low-power, capacitor-programmable reset supervision for space- and energy-constrained µP systems where accurate voltage thresholding and flexible timeout control are essential.

FAQ

What is the exact reset threshold voltage of the MAX6423XS25+ and how is it trimmed?

The MAX6423XS25+ has a nominal reset threshold of 2.5V, factory-trimmed using laser adjustment of on-chip resistors. At +25°C, the threshold is guaranteed within ±1.5% (2.463V to 2.538V); over –40°C to +125°C, tolerance widens to ±2.5%. This precision enables reliable detection of 2.5V supply faults without external calibration. The MAX6423XS25+ achieves this accuracy through matched BiCMOS process elements and post-package trimming verification.

How do I calculate the reset timeout period for the MAX6423XS25+ given a specific capacitor value?

Use the formula tRP = (2.73 × 10⁶) × CSRT + 275µs, where tRP is in seconds and CSRT is in farads. For example, a 1500pF capacitor yields tRP ≈ 4.375ms. The MAX6423XS25+ uses a 240nA internal current source charging CSRT to 0.65V; ceramic capacitors with leakage <10nA are mandatory. The MAX6423XS25+ datasheet confirms this relationship across temperature and supply voltage variations.

Can the MAX6423XS25+ drive a reset line referenced to a different supply voltage than VCC?

Yes-the MAX6423XS25+ features an open-drain RESET output, allowing connection of an external pullup resistor to any voltage between 0V and 5.5V. This enables direct interfacing with MCUs operating at 1.8V, 3.3V, or 5V logic levels independent of the MAX6423XS25+'s own VCC. The MAX6423XS25+ itself draws power only from VCC and imposes no voltage limitation on the pullup target, making it ideal for mixed-supply systems.

What is the minimum VCC voltage at which the MAX6423XS25+ guarantees valid RESET assertion?

The MAX6423XS25+ guarantees valid RESET assertion down to VCC = 1.0V, as specified in the Absolute Maximum Ratings and Electrical Characteristics tables. Below 1V, sink capability degrades significantly. This feature ensures robust reset behavior during deep brownout events common in battery-powered systems. The MAX6423XS25+ maintains full functionality-including threshold detection and timeout timing-throughout its 1.0V to 5.5V operating range.

Is the MAX6423XS25+ pin-compatible with other devices in the MAX642x family?

Yes-the MAX6423XS25+ shares identical pinout and package (SC70-4) with MAX6421XS25+ and MAX6422XS25+, differing only in RESET output type (open-drain vs. push-pull active-low/high). All three use pins 1=GND, 2=RESET, 3=N.C., 4=VCC. This allows drop-in replacement when changing reset logic polarity or drive strength, provided external circuitry (e.g., pullup for open-drain) is compatible. The MAX6423XS25+ pin map is validated per Maxim's Pin Configurations diagram.