Analog Devices Inc./Maxim Integrated MAX6423XS26+

Overview

MAX6423XS26+ from Maxim Integrated is a low-power microprocessor supervisor IC with open-drain active-low reset output, 2.625V factory-trimmed reset threshold, and capacitor-adjustable reset timeout (275µs base + 2.73s/F × CSRT). It monitors VCC from 1.0V to 5.5V and guarantees valid reset assertion down to VCC = 1V. Used in battery-powered controllers and medical equipment for reliable power-up/brownout detection.

For engineers reviewing the MAX6423XS26+ datasheet, MAX6423XS26+ pinout, MAX6423XS26+ application, or MAX6423XS26+ equivalent, key selection criteria include its SC70-4 package, 1.6µA quiescent current, open-drain RESET compatibility with multiple supply rails, and immunity to sub-50µs VCC transients at 100mV overdrive.

Technical Context

This device implements a precision voltage monitor with laser-trimmed resistive divider to set the 2.625V reset threshold (±2.5% over -40°C to +125°C), coupled to an internal 240nA current source that charges an external capacitor on the SRT pin to generate the programmable reset timeout delay.

The open-drain RESET output requires an external pullup and supports wired-OR configurations; it remains asserted until the SRT capacitor ramps to 0.65V after VCC exceeds the threshold, enabling precise timing control independent of VCC level.

Key Specifications

Pinout & Package

MAX6423XS26+ is housed in a 4-pin SC70-4 package (2.0mm × 1.25mm, 0.5mm pitch), optimized for space-constrained portable and medical PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6423XS26+, MAX6423US26-T offers identical electrical behavior in a larger package, while TLV809E26DBZR trades timeout adjustability for lower ICC and push-pull simplicity - both require layout and timing validation before substitution.

Availability

MAX6423XS26+ is available at Aetrix Electronics and suitable for battery-powered medical sensors, automotive body control modules, and portable industrial data loggers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6423XS26+ 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 in industrial, automotive, and medical markets.

The MAX6421–MAX6426 family delivers ultra-low-power, capacitor-programmable supervisors targeting space- and energy-constrained embedded systems requiring robust voltage monitoring and configurable reset timing.

FAQ

What is the exact reset threshold voltage of the MAX6423XS26+?

The MAX6423XS26+ has a factory-trimmed nominal reset threshold of 2.625V, with ±2.5% accuracy over the full -40°C to +125°C operating temperature range. This value is confirmed by the '26' suffix in the part number and specified in Table 1 of the datasheet. The MAX6423XS26+ uses laser-trimmed resistors to achieve this precision without external components.

Does the MAX6423XS26+ require an external pullup resistor on the RESET pin?

Yes, the MAX6423XS26+ features an open-drain RESET output and requires an external pullup resistor to establish a defined high state when not asserted. A 10kΩ to 100kΩ resistor to any supply rail ≤5.5V is recommended. The MAX6423XS26+ does not drive high actively; the pullup ensures proper logic levels for interfacing with µP reset inputs across diverse voltage domains.

How is the reset timeout period calculated for the MAX6423XS26+?

The reset timeout period tRP for the MAX6423XS26+ is calculated as tRP = (2.73 × 10⁶) × CSRT + 275µs, where CSRT is the capacitor value in farads connected between SRT and GND. For example, a 15nF capacitor yields ~41ms timeout. This formula is derived from the internal 240nA ramp current charging CSRT to a 0.65V threshold, and applies identically across all MAX6423XS26+ units.

Can the MAX6423XS26+ operate reliably below 1.6V VCC?

Yes, the MAX6423XS26+ is fully specified to operate down to VCC = 1.0V and guarantees valid RESET assertion as low as 1.0V. Its internal circuitry remains functional and the open-drain RESET output maintains sink capability down to this level. However, below 1.0V, RESET behavior is not guaranteed - the MAX6423XS26+ datasheet explicitly defines 1.0V as the minimum operational VCC.

What package type does the MAX6423XS26+ use, and what are its dimensions?

The MAX6423XS26+ uses the SC70-4 package: a 4-pin surface-mount outline measuring 2.0mm × 1.25mm with 0.5mm lead pitch. This compact footprint is documented in Maxim package drawing 21-0098 and is distinct from the SOT143-4 variant (MAX6423US26-T). The SC70-4 package enables high-density layouts in portable and medical PCBs where space is constrained.