Analog Devices Inc./Maxim Integrated MAX6392KA29

Overview

MAX6392KA29 from Maxim Integrated is a dual-voltage microprocessor supervisory circuit with sequenced reset outputs, monitoring VCC (2.93V factory-fixed threshold) and an adjustable secondary supply (RESET IN2), delivering push-pull RESET1 and open-drain RESET2 with 140ms minimum timeout periods, used in multivoltage power-up sequencing for industrial controllers and servers.

For engineers reviewing the MAX6392KA29 datasheet, MAX6392KA29 pinout, MAX6392KA29 application, or MAX6392KA29 equivalent, key selection criteria include its active-low manual reset (MR) input, guaranteed reset validity down to VCC = 1V, fixed 2.93V VCC threshold, and SOT23-8 package compatibility with tight thermal (-40°C to +85°C) and low-quiescent-current (15µA typical) requirements.

Technical Context

The MAX6392KA29 implements two independent voltage-monitoring comparators: one for VCC (with factory-trimmed 2.93V threshold) and one for RESET IN2 (625mV internal reference, adjustable via external resistor divider). RESET1 is push-pull and asserts before RESET2 during power-down; RESET2 is open-drain and deasserts only after RESET1, ensuring strict sequencing.

Its timing architecture uses internal counters for fixed 140ms (min) RESET1 timeout and either fixed 140ms (min) or capacitor-adjustable RESET2 timeout (via CSRT pin), with MR input asserting both resets synchronously and propagating with 10µs (RESET1) and 100ns (RESET2) delays - critical for deterministic system-level reset coordination.

Key Specifications

Pinout & Package

MAX6392KA29 is housed in an 8-pin SOT23 package (3.00mm × 1.75mm × 1.30mm body, 0.65mm pitch), rated for -40°C to +85°C operation, with gull-wing leads and JEDEC MO178 compliance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6391KA29 and TPS3808G33, the MAX6392KA29 uniquely combines push-pull RESET1, active-low MR, and dual-rail sequencing in SOT23-8 - making it the sole option for compact, manually triggered, multivoltage power-up coordination.

Availability

MAX6392KA29 is available at Aetrix Electronics and suitable for industrial PLCs, server motherboards, medical imaging subsystems, and automated test equipment requiring stable component supply with guaranteed long-term availability.

Supply support for MAX6392KA29 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 demanding industrial, computing, and communications applications.

The MAX6391/MAX6392 product line delivers dual-voltage supervisory circuits with sequenced reset outputs specifically for reliable power-up/down coordination in multirail embedded systems.

FAQ

What is the factory-trimmed VCC reset threshold voltage for MAX6392KA29?

The MAX6392KA29 has a factory-trimmed VCC reset threshold of 2.93V, with a tolerance of ±75mV (2.85V to 3.00V) over the full -40°C to +85°C temperature range. This value is laser-trimmed during production and specified in the Electrical Characteristics table. The MAX6392KA29 uses this precise threshold to initiate reset assertion when the primary supply falls below specification, ensuring consistent brownout detection without external calibration.

Does MAX6392KA29 support adjustable reset timeout for both RESET1 and RESET2?

No - only RESET2 timeout is adjustable on the MAX6392KA29. RESET1 has a fixed minimum timeout of 140ms, internally generated and non-configurable. RESET2 timeout can be set to a fixed 140ms (min) by connecting the CSRT pin to VCC, or made user-adjustable by connecting CSRT to an external capacitor (e.g., 1500pF yields ~3.1ms). This asymmetry ensures primary reset stability while allowing fine-grained control over secondary rail sequencing in the MAX6392KA29.

How does the manual reset (MR) input affect RESET1 and RESET2 timing in MAX6392KA29?

The MR input on the MAX6392KA29 asserts both RESET1 and RESET2 simultaneously upon falling edge, with RESET2 activating 100ns before RESET1 (tMR2 = 100ns, tMR1 = 10µs). After MR is released, RESET1 deasserts after its fixed 140ms timeout, and RESET2 deasserts after its configured timeout (140ms min or capacitor-adjusted), always following RESET1. This behavior ensures deterministic, skew-controlled manual reset coordination - a defining feature of the MAX6392KA29 not present in the MAX6391 variant.

Can MAX6392KA29 monitor a 1.2V supply as the secondary voltage (RESET IN2)?

Yes - the MAX6392KA29 can monitor a 1.2V supply on RESET IN2 using an external resistive divider. Since the internal RESET IN2 comparator reference is fixed at 625mV, a divider with R3 = 460kΩ and R4 = 500kΩ yields VRST = 625mV × (460k + 500k)/500k ≈ 1.2V. The MAX6392KA29's high-impedance input (50nA max leakage) ensures minimal loading, and the design supports thresholds down to 625mV - making it suitable for supervising modern low-voltage rails like 1.2V, 1.8V, or 2.5V when paired with appropriate resistors.

What is the minimum VCC voltage at which MAX6392KA29 guarantees valid reset operation?

The MAX6392KA29 guarantees valid reset assertion and deassertion functionality down to VCC = 1.0V, as explicitly stated in the Electrical Characteristics table under "Reset Pullup Resistance" and confirmed in the Detailed Description section. This capability allows the MAX6392KA29 to maintain supervision during deep brownout events where other supervisors fail, ensuring µP remains held in reset until the supply recovers sufficiently - a critical reliability feature for mission-critical industrial and medical applications.