Analog Devices Inc./Maxim Integrated MAX6392KA22

Overview

MAX6392KA22 from Maxim Integrated is a dual-voltage microprocessor supervisory circuit with sequenced reset outputs for multi-rail systems. It monitors VCC (master supply) at 2.19V threshold and RESET IN2 (adjustable secondary supply), provides push-pull RESET1 and open-drain RESET2 with 140ms minimum timeout, and includes active-low manual reset (MR). Used in servers and industrial controllers requiring controlled power-up sequencing.

For engineers reviewing the MAX6392KA22 datasheet, MAX6392KA22 pinout, MAX6392KA22 application, or MAX6392KA22 equivalent, this page delivers verified timing behavior, reset sequencing logic, MR input timing, CSRT capacitor-adjustable timeout, and SOT23-8 package integration details critical for reliable system-level reset design.

Technical Context

The MAX6392KA22 implements two independent voltage monitoring paths: VCC triggers both RESET1 and RESET2 when falling below 2.19V, while RESET IN2 (threshold = 625mV) independently asserts RESET2 only. RESET1 deasserts ≥140ms after VCC exceeds 2.19V; RESET2 deasserts ≥140ms (or user-adjusted via CSRT capacitor) after both VCC and RESET IN2 exceed thresholds, and always follows RESET1 during power-up.

Its internal architecture includes a 600nA current source for CSRT-based timeout adjustment, 47kΩ internal MR pullup to VCC, and separate fixed-delay counter chain when CSRT is tied to VCC. RESET1 is push-pull (MAX6392-specific), RESET2 is open-drain, and both outputs remain valid down to VCC = 1.0V.

Key Specifications

Pinout & Package

MAX6392KA22 is housed in an 8-pin SOT23 package (JEDEC MO-178 compliant, 3.00mm × 1.75mm body, 0.65mm pitch). Pin 1 is marked with a dot; leads are gull-wing, coplanarity ≤ 0.1mm.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-supply supervisory applications.

Compared with MAX6392KA22, MAX6392KA23 offers a higher VCC threshold for improved noise margin in 2.5V systems, while TPS3808G125 lacks RESET IN2 monitoring and sequenced outputs-making it unsuitable for applications requiring coordinated dual-rail reset timing.

Availability

MAX6392KA22 is available at Aetrix Electronics and suitable for industrial PLC controllers, server motherboards, medical diagnostic equipment, and data acquisition systems requiring stable component supply, long-term lifecycle support, and guaranteed reset sequencing integrity.

Supply support for MAX6392KA22 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, mixed-signal, and power management ICs for industrial, computing, and communications applications.

The MAX6392KA22 belongs to Maxim's µP supervisory product line, engineered specifically for deterministic power-up/down sequencing in multi-voltage embedded systems where reset timing integrity directly impacts system reliability.

FAQ

What is the exact VCC reset threshold voltage for MAX6392KA22?

The MAX6392KA22 has a factory-trimmed VCC reset threshold of 2.19V nominal, with guaranteed range of 2.12V (min) to 2.25V (max) over -40°C to +85°C. This value is laser-trimmed during production and applies exclusively to the MAX6392KA22 variant - other suffixes (e.g., KA23, KA26) have different thresholds. The threshold is referenced internally and does not require external components.

How does the manual reset (MR) input affect both reset outputs in MAX6392KA22?

When MR is pulled low, MAX6392KA22 immediately asserts both RESET1 (push-pull) and RESET2 (open-drain) active-low outputs. RESET2 asserts within 100ns and RESET1 within 10µs of MR falling edge. Both remain asserted for their respective timeout periods (≥140ms) after MR returns high. The internal 47kΩ MR pullup ensures default HIGH state when left unconnected.

Can MAX6392KA22 monitor a 1.2V supply as the secondary voltage (RESET IN2)?

Yes - the MAX6392KA22 RESET IN2 input uses a fixed 625mV internal reference, so a 1.2V supply can be monitored using an external resistor divider. For example, with R3 = 450kΩ and R4 = 500kΩ, the divider yields 625mV at RESET IN2 when input is 1.2V. The input leakage is only 50nA, minimizing divider current draw and enabling high-resistor values for low power.

What is the purpose of the CSRT pin on MAX6392KA22, and how is it configured?

The CSRT pin on MAX6392KA22 configures RESET2 timeout behavior: tying CSRT to VCC selects a fixed 140ms minimum delay, while connecting CSRT to a capacitor-to-ground enables user-adjustable delay (tRP2 = 2.08×10⁶ × CCSRT). For example, a 1500pF capacitor yields ~3.1ms; larger values scale linearly. The internal 600nA current source charges the capacitor to 1.25V for timing comparison.

Does MAX6392KA22 remain functional when VCC drops below 2.19V but stays above 1.0V?

Yes - MAX6392KA22 guarantees valid reset output operation down to VCC = 1.0V, meaning RESET1 and RESET2 continue asserting correctly even during severe brownout conditions where VCC sags from 2.19V down to 1.0V. This ensures µP remains held in reset until supply recovers sufficiently, preventing erratic execution or memory corruption.