Analog Devices Inc./Maxim Integrated MAX6422XS44

Overview

MAX6422XS44 from Maxim Integrated is a low-power microprocessor reset supervisor IC in SC70-4 package, featuring an active-high push-pull RESET output, 4.375V nominal reset threshold (±2.5% over temperature), capacitor-adjustable reset timeout (275µs base + 2.73×10⁶ × CSRT), and guaranteed operation down to VCC = 1V. It monitors supply voltage during power-up, brownout, and power-down in portable battery-powered controllers.

For engineers reviewing the MAX6422XS44 datasheet, MAX6422XS44 pinout, MAX6422XS44 application, or MAX6422XS44 equivalent, this page provides verified functional identity, validated SC70-4 pin mapping, confirmed 4.375V threshold accuracy, true reset timeout calculation method, and two manufacturer-validated alternative parts for voltage supervisor selection.

Technical Context

The MAX6422XS44 implements a precision bandgap-based voltage reference with laser-trimmed resistors to set its 4.375V reset threshold, maintaining ±2.5% accuracy across –40°C to +125°C. Its internal 240nA current source charges an external capacitor on the SRT pin to generate a ramp voltage compared against a fixed 0.65V internal reference, determining reset deassertion timing.

Unlike open-drain variants, the MAX6422XS44 uses a push-pull output stage capable of sourcing up to 800µA at VCC ≥ 4.5V while maintaining VOH ≥ 0.8×VCC and sinking up to 3.2mA with VOL ≤ 0.4V - enabling direct interface to CMOS µP reset inputs without external pull-up components.

Key Specifications

Pinout & Package

MAX6422XS44 is housed in a 4-pin SC70-4 package (outline 21-0098), with 0.65mm pitch, 1.3mm × 1.0mm body size, and thermal pad not connected internally. Pin 1 is marked by a dot or beveled corner.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6422XS44, MAX6422US44-T offers identical functionality in a mechanically distinct but pin-compatible SOT143 package, whereas TLV803SDBZR trades timeout adjustability for smaller size and lower cost in fixed-delay applications.

Availability

MAX6422XS44 is available at Aetrix Electronics and suitable for portable medical sensors, battery-powered industrial controllers, and automotive body control modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX6422XS44 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 connectivity in harsh environments.

The MAX6421–MAX6426 family delivers ultra-low-power, capacitor-programmable reset supervision for battery-critical and automotive applications where supply stability and deterministic reset timing are essential.

FAQ

What is the exact reset threshold voltage of MAX6422XS44 and how is it trimmed?

The MAX6422XS44 has a nominal reset threshold of 4.375V, corresponding to suffix "44" per Table 1 in the datasheet. This value is factory-laser-trimmed with ±1.5% accuracy at +25°C and ±2.5% over –40°C to +125°C. The trimming is performed on-chip using laser-fused resistors within the voltage reference circuit, ensuring stable performance without external calibration. MAX6422XS44 maintains this accuracy across its full operating temperature range and supply voltage range (1.0V to 5.5V).

How do I calculate the reset timeout period for MAX6422XS44 using the SRT capacitor?

The reset timeout period (tRP) for MAX6422XS44 is calculated as 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 internal 240nA current source charges CSRT to a 0.65V reference; leakage must be <10nA, so X7R or C0G ceramic capacitors are recommended. MAX6422XS44's timeout is fully determined by this external capacitor and does not vary with temperature or supply voltage.

Does MAX6422XS44 require an external pull-up resistor on the RESET pin?

No, MAX6422XS44 does not require an external pull-up resistor because it features an active-high push-pull RESET output. The output actively drives high (VOH ≥ 0.8×VCC) and low (VOL ≤ 0.4V at 3.2mA) without external components. This distinguishes it from open-drain variants like MAX6423XS44. MAX6422XS44's push-pull architecture simplifies design, reduces BOM count, and ensures fast, rail-to-rail reset transitions compatible with standard CMOS microcontrollers.

Can MAX6422XS44 operate reliably when VCC drops below 1.5V?

Yes, MAX6422XS44 is guaranteed to assert and maintain a valid RESET signal down to VCC = 1.0V, as specified in the Electrical Characteristics table. Its internal reference and output stage remain functional across the full 1.0V to 5.5V supply range. Below 1.0V, RESET behavior is not characterized. For applications requiring logic validity down to 0V, a 100kΩ pull-up resistor from RESET to VCC is recommended - a practice explicitly documented for MAX6422 in the datasheet. MAX6422XS44 meets this requirement without additional circuitry above 1.0V.

What package and marking code does MAX6422XS44 use?

MAX6422XS44 is supplied in a 4-pin SC70-4 package (package code X4+1, outline 21-0098) with a top-marking code of "ADM". The "XS" in the part number denotes SC70 packaging, and "44" specifies the 4.375V reset threshold. This marking appears laser-etched on the top surface of the device. The SC70-4 footprint measures 1.3mm × 1.0mm with 0.65mm lead pitch, and the thermal pad is not electrically connected - consistent with Maxim's published land pattern 90-0187. MAX6422XS44 is available in tape-and-reel only, with lead-free compliance indicated by the "+T" suffix in ordering codes.