Analog Devices Inc./Maxim Integrated MAX6390XS23D4

Overview

MAX6390XS23D4 from Maxim Integrated is a low-power microprocessor supervisory circuit with open-drain active-low reset output, factory-set 2.3V reset threshold (±2.5% over -40°C to +125°C), 1120ms VCC reset timeout, and 140ms manual reset timeout. It monitors single-supply voltages from +1.8V to +5.0V and consumes only 3µA at +1.8V, used in portable battery-powered equipment for reliable power-on reset and brownout protection.

For engineers reviewing the MAX6390XS23D4 datasheet, MAX6390XS23D4 pinout, MAX6390XS23D4 application, or MAX6390XS23D4 equivalent, key selection criteria include its 2.3V reset threshold accuracy, dual timeout timing (1120ms/140ms), SC70-4 package footprint, open-drain output requiring external pull-up, and guaranteed reset validity down to VCC = 1V.

Technical Context

The MAX6390XS23D4 implements a precision bandgap-based voltage comparator with ±2.5% threshold accuracy across -40°C to +125°C and 60ppm/°C tempco. Its internal timer generates fixed 1120ms reset assertion after VCC recovery and 140ms assertion after MR release.

It features an internal 1.56kΩ pull-up resistor on the MR input-significantly lower than standard 63kΩ in earlier variants-enabling faster MR release timing and improved noise immunity in high-EMI environments. The open-drain RESET output supports flexible logic-level interfacing with external pull-up to any rail up to +6.0V.

Key Specifications

Pinout & Package

MAX6390XS23D4 is housed in a lead-free 4-pin SC70 package (X4-1, 1.3mm × 1.1mm × 0.6mm), optimized for space-constrained portable designs. Pin 1 = VCC, Pin 2 = RESET, Pin 3 = MR, Pin 4 = GND.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6326XR23D4 and TPS3808G125DBVR, the MAX6390XS23D4 uniquely combines open-drain output, ultra-low 3µA quiescent current at 1.8V, and a fast-release 1.56kΩ MR pull-up-making it optimal for battery-sensitive, noise-prone, and multi-rail embedded systems requiring field-serviceable reset.

Availability

MAX6390XS23D4 is available at Aetrix Electronics and suitable for portable medical sensors, smart meter battery backup, industrial PLC I/O modules, and automotive body control units requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6390XS23D4 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 computing applications, with emphasis on low-power, high-reliability solutions.

The MAX6390XS23D4 belongs to the MAX6381–MAX6390 family of ultra-low-power µP supervisory circuits, engineered specifically for battery-operated and energy-harvesting systems where supply rail integrity and deterministic reset behavior are mission-critical.

FAQ

What is the exact reset threshold voltage of MAX6390XS23D4 and how stable is it over temperature?

The MAX6390XS23D4 has a factory-set reset threshold of 2.3V with ±2.5% accuracy over the full operating range of -40°C to +125°C. Its temperature coefficient is 60ppm/°C, meaning the threshold drifts less than 15mV across the entire temperature span-critical for maintaining consistent brownout detection in automotive and industrial environments where ambient temperature varies widely.

Does MAX6390XS23D4 support manual reset, and what is unique about its MR input?

Yes, MAX6390XS23D4 includes an active-low manual reset (MR) input with an internal 1.56kΩ pull-up resistor to VCC-distinctly lower than the 63kΩ found in MAX6384–MAX6386. This design reduces the MR release time constant, minimizes susceptibility to noise-induced false resets, and enables faster, more reliable reset initiation in electrically noisy applications such as motor drives or industrial control panels.

What are the timing specifications for reset assertion and deassertion in MAX6390XS23D4?

MAX6390XS23D4 provides two independent timeout periods: a 1120ms minimum VCC reset timeout (after VCC rises above 2.3V) and a 140ms minimum manual reset timeout (after MR returns high). Both are guaranteed minimum values; actual durations may be longer due to process variation but will never fall short-ensuring µP firmware always receives sufficient reset hold time for safe initialization.

Can MAX6390XS23D4 operate reliably at very low supply voltages?

Yes, MAX6390XS23D4 guarantees correct reset output logic state down to VCC = 1.0V, and operates across a full 1.0V to 5.5V supply range. Its open-drain RESET output remains functional and sinks current even at 1.0V (with 80µA sink capability), making it suitable for ultra-low-voltage applications like energy-harvesting nodes or deep-brownout recovery sequences where other supervisors fail.

What package type and pinout does MAX6390XS23D4 use, and is it compatible with automated assembly?

MAX6390XS23D4 uses a RoHS-compliant 4-pin SC70 package (X4-1, 1.3mm × 1.1mm × 0.6mm) with standard gull-wing leads. Its pinout-Pin 1: VCC, Pin 2: RESET, Pin 3: MR, Pin 4: GND-is fully compatible with standard SMT pick-and-place equipment and reflow profiles per JEDEC J-STD-020. The small footprint supports high-density PCB layouts in wearables and miniaturized IoT endpoints.