Analog Devices Inc./Maxim Integrated MAX6419UK31

Overview

MAX6419UK31 from Maxim Integrated is a low-power microprocessor reset supervisor IC with capacitor-adjustable reset timeout, 3.075V factory-trimmed reset threshold, open-drain active-low RESET output, and SOT23-5 package. It monitors VCC from 1.6V to 5V, asserts reset below threshold, holds reset for user-defined timeout after VCC recovery, and guarantees valid operation down to VCC = 1V. It is used in battery-powered controllers requiring precise brownout protection.

For engineers reviewing the MAX6419UK31 datasheet, MAX6419UK31 pinout, MAX6419UK31 application, or MAX6419UK31 equivalent, key selection criteria include reset threshold accuracy (±2.5% over -40°C to +125°C), ultra-low quiescent current (1.6µA typ), capacitor-programmable timeout (275µs base + 2.73×10⁶ × CSRT), open-drain logic compatibility with multiple supply rails, and guaranteed reset validity at VCC ≥ 1V.

Technical Context

The MAX6419UK31 implements a precision voltage monitor with laser-trimmed internal reference and a current-source–capacitor timing circuit. Its SRT pin sources a stable 240nA ramp current into an external capacitor to generate the reset timeout period, with deassertion triggered when capacitor voltage reaches 0.65V.

It features hysteresis of 4×VTH (≈12.3mV at 3.075V), immunity to short VCC transients (e.g., ≤50µs for 100mV overdrive), and a VCC-to-reset delay of 80µs during falling-edge detection. The open-drain RESET output supports wired-OR configurations and logic-level interfacing up to 5.5V via external pullup.

Key Specifications

Pinout & Package

MAX6419UK31 is housed in a 5-pin SOT23-5 package with exposed pad (RoHS-compliant, lead-free option available as MAX6419UK31+T). Pin 1 = VCC, Pin 2 = GND, Pin 3 = RESET (open-drain), Pin 4 = N.C., Pin 5 = SRT.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NCP302LSN30T1G and TLV809K33DBZR, MAX6419UK31 uniquely combines factory-trimmed 3.075V detection, capacitor-programmable timeout (275µs–seconds), and open-drain output-enabling precise brownout response tuning and multi-rail compatibility not achievable with fixed-delay alternatives.

Availability

MAX6419UK31 is available at Aetrix Electronics and suitable for battery-powered medical monitors, automotive body control modules, industrial sensor nodes, and POS terminal power management requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6419UK31 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 industrial, automotive, communications, and computing applications.

The MAX6421–MAX6426 family delivers low-power, capacitor-programmable reset supervisors targeting space-constrained, battery-sensitive systems where accurate voltage monitoring and flexible timeout control are essential.

FAQ

What is the exact reset threshold voltage of MAX6419UK31 and how is it trimmed?

The MAX6419UK31 has a factory-laser-trimmed nominal reset threshold of 3.075V, with guaranteed accuracy of ±2.5% over the full operating temperature range (-40°C to +125°C). This value corresponds to suffix "31" in Table 1 of the datasheet, and is achieved using on-chip laser-trimmed resistors to set the internal voltage comparator reference. The MAX6419UK31 does not require external components to achieve this precision.

How do I calculate the external capacitor value for a desired reset timeout on MAX6419UK31?

To set a specific reset timeout tRP (in seconds) for MAX6419UK31, use the formula CSRT = (tRP − 275µs) / 2.73×10⁶, where CSRT is in farads. For example, a 100ms timeout requires CSRT = (0.1 − 0.000275) / 2.73×10⁶ ≈ 36.4nF. Use low-leakage ceramic capacitors (≤10nA leakage); avoid electrolytics or high-K dielectrics that degrade timing accuracy.

Can MAX6419UK31 drive a 5V microcontroller reset input while powered from a 3.3V supply?

Yes. The MAX6419UK31 features an open-drain RESET output rated to 5.5V. When powered from 3.3V VCC, connect a pullup resistor (e.g., 47kΩ) from the RESET pin to the 5V µP reset rail. During reset assertion, the output pulls low; during deassertion, the external pullup raises RESET to 5V - enabling seamless level translation without additional logic.

Does MAX6419UK31 remain functional during cold-crank automotive conditions where VCC drops to 2.5V?

Yes. The MAX6419UK31 operates over VCC = 1.0V to 5.5V and guarantees valid reset assertion/deassertion down to VCC = 1V. At 2.5V, it fully meets all specifications: reset threshold remains 3.075V ±2.5%, SRT current stays at 240nA, and RESET sink capability exceeds 50µA - making it suitable for ISO 16750-2 cold-crank compliance in automotive modules.

Is there a pin-compatible replacement for MAX6419UK31 with identical functionality?

No Maxim-recommended pin-compatible drop-in replacement exists for MAX6419UK31. While MAX6425UK31 and MAX6426UK31 share the same SOT23-5 package and open-drain output, they differ in pinout: MAX6425UK31 places RESET on pin 3 and SRT on pin 5 (same as MAX6419UK31), but MAX6426UK31 swaps RESET and SRT pins. Always verify pin mapping before substitution; MAX6419UK31 is not interchangeable with MAX6426UK31 without PCB revision.