Analog Devices Inc./Maxim Integrated MAX6414UK44+

Overview

MAX6414UK44+ from Maxim Integrated is a low-power, single-voltage microprocessor reset supervisor IC with factory-trimmed 4.375V VCC reset threshold, active-low open-drain RESET output, manual reset input (MR), and capacitor-adjustable reset timeout delay. It monitors supply voltage in battery-powered controllers and embedded systems, asserting reset during brownout or power-up until the external SRT capacitor discharges to 0.65V.

For engineers reviewing the MAX6414UK44+ datasheet, MAX6414UK44+ pinout, MAX6414UK44+ application, or MAX6414UK44+ equivalent, key selection criteria include guaranteed reset validity down to VCC = 1V, 1.7µA typical quiescent current, ±2.5% VTH accuracy over -40°C to +125°C, and compatibility with logic supplies up to 5.5V via open-drain output.

Technical Context

The MAX6414UK44+ implements a precision bandgap-based voltage comparator for VCC monitoring and a 240nA constant-current ramp source tied to the SRT pin to generate programmable timeout delays. Its internal 20kΩ MR pullup enables direct switch-to-ground manual reset without external components.

Reset assertion occurs when VCC falls below 4.375V (±2.5%), MR is pulled low, or both; deassertion requires VCC > 4.375V, MR high, and SRT capacitor voltage ≥ 0.65V - ensuring reliable power sequencing in automotive and medical equipment where transient immunity and temperature-stable thresholds are critical.

Key Specifications

Pinout & Package

SOT23-5 package (5-pin, 2.9mm × 1.6mm, 0.95mm height), RoHS-compliant lead-free construction denoted by '+' suffix.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6414UK44+, MAX6414UK43+ offers tighter voltage matching for 4.2V systems but sacrifices 175mV margin against overvoltage; TPS3808G33DBVR reduces current draw by 0.6µA but removes manual reset and timeout flexibility - making MAX6414UK44+ optimal for 4.4V battery-backed controllers requiring field-service reset capability.

Availability

MAX6414UK44+ is available at Aetrix Electronics and suitable for automotive engine control units, portable medical devices, industrial PLC modules, and battery-backed real-time clock systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6414UK44+ 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 medical applications, emphasizing low power, high reliability, and temperature stability.

The MAX6412–MAX6420 product line delivers configurable µP reset supervision with capacitor-timed delays and multiple threshold options, targeting applications where supply monitoring must remain robust across extreme temperatures and low-energy constraints.

FAQ

What is the exact reset threshold voltage of MAX6414UK44+ and how is it trimmed?

The MAX6414UK44+ has a factory-trimmed VCC reset threshold of 4.375V (nominal), with ±2.5% accuracy guaranteed over -40°C to +125°C. This value corresponds to suffix "44" per Table 1 in the datasheet. Trimming is performed using laser-adjusted on-chip resistors during final test, eliminating the need for external components and ensuring consistent performance across production lots.

Can MAX6414UK44+ monitor voltages other than VCC?

No - the MAX6414UK44+ is configured exclusively for single-voltage VCC monitoring with a fixed 4.375V threshold. Unlike MAX6415–MAX6420 variants, it lacks the RESET IN pin required for adjustable external voltage monitoring. To supervise auxiliary rails (e.g., 3.3V, 1.8V), select MAX6418UK33+ (dual-threshold) or MAX6415UK-T (adjustable).

How do I calculate the SRT capacitor value for a 500ms reset timeout with MAX6414UK44+?

Use the formula tRP = (2.71 × 10⁶) × CSRT + 275µs, solving for CSRT: CSRT = (tRP − 275µs) / 2.71 × 10⁶. For tRP = 500ms = 0.5s: CSRT = (0.5 − 0.000275) / 2,710,000 ≈ 184nF. Use a low-leakage ceramic capacitor (X7R/C0G) rated ≥10V; avoid electrolytics or high-DF types that degrade timing accuracy.

Is MAX6414UK44+ compatible with 3.3V microcontrollers despite its 4.375V threshold?

Yes - the MAX6414UK44+'s open-drain RESET output can interface directly to 3.3V µP reset pins using a 3.3V pullup resistor. Its 4.375V VCC threshold applies only to the monitored supply rail (e.g., a 4.4V LDO output powering the µP's VDD), not the logic level of the reset signal. This decoupling enables use in mixed-voltage systems.

Does MAX6414UK44+ require an external pullup resistor on the RESET pin?

Yes - because MAX6414UK44+ features an active-low open-drain RESET output, an external pullup resistor to the target µP's logic supply (e.g., 3.3V or 5V) is mandatory. Typical values range from 4.7kΩ to 10kΩ. Without this pullup, RESET remains floating and cannot drive a valid high logic level to the µP's reset input.