Analog Devices Inc./Maxim Integrated MAX6423XS22+T

Overview

MAX6423XS22+T from Analog Devices is a low-power microprocessor supervisor IC with open-drain active-low reset output, 2.188V ±2.5% factory-trimmed reset threshold, capacitor-adjustable reset timeout (3.0–5.75ms with 1500pF), and guaranteed operation down to VCC = 1V. It monitors supply voltage in portable and battery-powered systems to prevent erroneous code execution during power-up, brownout, or power-down.

For engineers reviewing the MAX6423XS22+T datasheet, MAX6423XS22+T pinout, MAX6423XS22+T application, or MAX6423XS22+T equivalent, key selection criteria include its SC70-4 package, 1.6µA typical quiescent current, open-drain logic compatibility with multiple supply rails, immunity to short VCC transients, and precise 240nA SRT ramp current for accurate timeout setting.

Technical Context

The MAX6423XS22+T implements a precision voltage-detection architecture using laser-trimmed resistors to set its 2.188V reset threshold with ±2.5% accuracy over –40°C to +125°C. Its reset assertion is triggered solely by VCC falling below this threshold, with no watchdog or manual reset input.

Reset deassertion relies on an internal 240nA current source charging an external capacitor (CSRT) from the SRT pin to a 0.65V ramp threshold; timing is governed by tRP = 2.73×10⁶ × CSRT + 275µs. The open-drain RESET output requires an external pullup and remains valid for VCC ≥ 1.0V.

Key Specifications

Pinout & Package

MAX6423XS22+T is housed in a 4-pin SC70-4 package (outline 21-0098), measuring 2.0mm × 2.1mm × 0.95mm, with wettable flank leads for automated optical inspection.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6423XS22+T, MAX6423US22+T offers identical functionality in a mechanically distinct but electrically pin-compatible package, while TLV803EB22DBZR trades timeout flexibility and open-drain versatility for lower cost and smaller solution size in fixed-timing applications.

Availability

MAX6423XS22+T is available at Aetrix Electronics and suitable for portable medical sensors, battery-powered industrial controllers, and automotive body control modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6423XS22+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 was designed specifically for ultra-low-power, capacitor-programmable reset supervision in space-constrained, battery-sensitive applications where precision threshold accuracy and brownout resilience are critical.

FAQ

What is the exact reset threshold voltage of MAX6423XS22+T?

The MAX6423XS22+T features a factory-laser-trimmed reset threshold of 2.188V, with ±1.5% accuracy at +25°C and ±2.5% over the full –40°C to +125°C operating range. This value corresponds to the "22" suffix per Table 1 in the datasheet and is verified by production testing, not nominal approximation.

Does MAX6423XS22+T require an external capacitor to function?

MAX6423XS22+T operates as a basic voltage detector without an external capacitor when the SRT pin is left floating, providing immediate reset assertion/deassertion. However, to enable the programmable reset timeout feature-critical for meeting µP minimum reset pulse width requirements-an external capacitor must be connected between SRT and GND.

Can MAX6423XS22+T drive a 5V microcontroller reset input?

Yes, MAX6423XS22+T's open-drain RESET output can interface directly with a 5V µP reset input by connecting the external pullup resistor to the 5V rail. The device's RESET pin is rated to +6.0V, and its leakage current remains below 1.0µA when deasserted, ensuring clean logic-high levels across voltage domains.

What is the minimum VCC required for MAX6423XS22+T to assert a valid reset signal?

MAX6423XS22+T guarantees valid RESET output behavior down to VCC = 1.0V. Below this, sink capability degrades rapidly; for applications requiring asserted reset down to 0V, a 100kΩ pulldown resistor from RESET to GND is recommended to prevent floating states during deep undervoltage conditions.

How does the SRT pin timing mechanism work in MAX6423XS22+T?

The SRT pin hosts a precision 240nA current source that charges an external capacitor to 0.65V. Once VCC rises above the 2.188V threshold, the capacitor begins ramping; RESET deasserts only upon reaching 0.65V. The formula tRP = 2.73×10⁶ × CSRT + 275µs defines the timeout, making timing predictable and independent of VCC variation.