Analog Devices Inc./Maxim Integrated MAX6389XS22D3+

Overview

MAX6389XS22D3+ from Maxim Integrated is a low-power microprocessor supervisory circuit with open-drain active-low reset output, factory-set 2.19V VCC reset threshold (±2.5% over -40°C to +125°C), 140ms minimum reset timeout, and auxiliary RESET IN input for dual-voltage monitoring. It operates from 1.0V to 5.5V supply and consumes only 3μA at 1.8V, targeting battery-powered embedded systems requiring reliable power-up/brownout detection.

For engineers reviewing the MAX6389XS22D3+ datasheet, MAX6389XS22D3+ pinout, MAX6389XS22D3+ application, or MAX6389XS22D3+ equivalent, key selection criteria include its 2.19V reset threshold accuracy, 140ms VCC timeout, open-drain output requiring external pullup, RESET IN comparator referenced to 1.27V, and 4-pin SC70 package compatibility with space-constrained designs.

Technical Context

The MAX6389XS22D3+ integrates a precision voltage comparator for VCC monitoring and a separate high-impedance RESET IN comparator referenced to an internal 1.27V bandgap. Reset assertion occurs when either VCC falls below 2.19V or RESET IN drops below 1.27V, with independent timing control ensuring deterministic behavior during dual-rail brownouts.

Its open-drain RESET output guarantees valid logic state down to VCC = 1.0V and supports wired-OR configurations. The device features negative-going VCC transient immunity up to 35µs for 100mV overdrive, and includes built-in glitch rejection on the RESET IN input (100ns minimum pulse rejection).

Key Specifications

Pinout & Package

MAX6389XS22D3+ uses a 4-pin SC70 package (outline 21-0098, land pattern 90-0187) with 0.65mm pitch and RoHS-compliant lead-free finish (+ suffix). Pin 1 is VCC, Pin 2 is RESET (open-drain active-low), Pin 3 is RESET IN, and Pin 4 is GND.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6389XS22D3+, the μDFN variant offers superior thermal dissipation in thermally constrained environments, while the TLV809K22DBZR trades dual-monitoring capability for lower cost and smaller 3-pin footprint-making it suitable only for single-rail systems without auxiliary voltage tracking needs.

Availability

MAX6389XS22D3+ is available at Aetrix Electronics and suitable for industrial sensor nodes, medical wearables, automotive body control modules, and smart home hubs requiring stable component supply and long-term lifecycle support.

Supply support for MAX6389XS22D3+ 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 healthcare applications, emphasizing low power, high reliability, and AEC-Q100 qualification.

The MAX6381–MAX6390 family delivers single/dual low-voltage supervisory circuits optimized for battery-powered and safety-critical systems where accurate reset timing and dual-rail fault detection are essential.

FAQ

What is the exact reset threshold voltage of MAX6389XS22D3+ and how stable is it over temperature?

The MAX6389XS22D3+ has a factory-set VCC reset threshold of 2.19V with ±2.5% accuracy over the full operating temperature range of -40°C to +125°C. This stability is achieved through laser-trimmed resistors and a precision bandgap reference, ensuring consistent brownout detection without external calibration. The device also exhibits low tempco (60ppm/°C), minimizing drift across thermal cycles.

Does MAX6389XS22D3+ support monitoring of two independent power rails simultaneously?

Yes, MAX6389XS22D3+ supports dual-rail supervision: VCC is monitored against its 2.19V threshold, while the RESET IN pin monitors a second voltage against an internal 1.27V reference. By connecting RESET IN to a resistor divider, users can set custom thresholds for auxiliary rails (e.g., 1.8V or 2.5V), and reset asserts if either rail fails - a key feature distinguishing it from single-supply supervisors.

What is the function of the RESET IN pin on MAX6389XS22D3+ and how is it configured?

The RESET IN pin on MAX6389XS22D3+ is a high-impedance input to a dedicated comparator referenced to 1.27V. To supervise a secondary voltage (e.g., 1.8V), connect RESET IN to the center node of a resistor divider between that rail and ground. The divider ratio sets the effective threshold using R1 = R2 × ((V_INTH/1.27V) − 1). Input leakage is ≤±50nA, allowing use of high-value resistors without accuracy loss.

What package type and footprint does MAX6389XS22D3+ use, and are land patterns available?

MAX6389XS22D3+ uses a 4-pin SC70 package (outline number 21-0098, land pattern 90-0187) with 0.65mm pitch and 1.6mm × 1.6mm body size. The RoHS-compliant lead-free version is indicated by the "+" suffix. Official land patterns and solder mask recommendations are published by Maxim Integrated and accessible via their package database at maximintegrated.com/packages.

How does the open-drain RESET output of MAX6389XS22D3+ differ from push-pull alternatives, and what external components are required?

The open-drain RESET output of MAX6389XS22D3+ requires an external pullup resistor to the host logic rail (e.g., 10kΩ to 3.3V) to define the inactive high state. This configuration enables wired-OR reset buses, level translation across voltage domains, and compatibility with legacy μP reset inputs expecting active-low open-drain signaling - unlike push-pull variants which drive both high and low internally.