Analog Devices Inc./Maxim Integrated MAX6392KA44+

Overview

MAX6392KA44+ from Maxim Integrated is a dual-voltage microprocessor supervisory circuit with sequenced reset outputs, monitoring VCC (4.38V 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 MAX6392KA44+ datasheet, MAX6392KA44+ pinout, MAX6392KA44+ application, or MAX6392KA44+ equivalent, key selection considerations include manual reset input timing (50µs min pulse width), guaranteed reset validity down to VCC = 1V, CSRT-configurable RESET2 delay, and SOT23-8 package compatibility with space-constrained embedded power management designs.

Technical Context

The MAX6392KA44+ implements two independent voltage comparators: one fixed-threshold (4.38V) monitor on VCC for primary reset generation, and a 625mV reference-based comparator on RESET IN2 for secondary supply supervision. RESET1 is push-pull active-low with internal 47kΩ pullup replaced by MR input.

Sequencing logic ensures RESET2 always deasserts after RESET1 during power-up and asserts before RESET1 during power-down. The CSRT pin selects between fixed 140ms (tied to VCC) or capacitor-adjustable RESET2 timeout, while MR forces synchronized assertion of both resets with 10µs skew between outputs.

Key Specifications

Pinout & Package

MAX6392KA44+ uses an 8-pin SOT23-8 package (3.00mm × 1.75mm × 1.30mm body, 0.65mm pitch), lead-free per RoHS, with exposed pad not electrically connected.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6392KA44+, the MAX6392KA46+ offers higher reset threshold for tighter 5V rail control, while the TPS3808G33DBVR provides simpler single-rail supervision in smaller package but cannot replace sequenced dual-supply functionality.

Availability

MAX6392KA44+ is available at Aetrix Electronics and suitable for industrial PLCs, server power management, medical imaging systems, and automated test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6392KA44+ 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 industrial, communications, and computing applications, emphasizing high reliability and low power.

The MAX6391/MAX6392 family was engineered specifically for multivoltage system power sequencing-ensuring deterministic reset ordering between primary and secondary rails in space-constrained embedded platforms.

FAQ

What is the exact VCC reset threshold voltage for MAX6392KA44+?

The MAX6392KA44+ has a factory-trimmed VCC reset threshold of 4.38V, with a guaranteed range of 4.25V to 4.50V across -40°C to +85°C. This value is laser-trimmed during production and is not user-adjustable. The MAX6392KA44+ datasheet specifies this as the nominal threshold for detecting brownout on the main supply rail, and it directly determines the minimum operating voltage before RESET1 assertion occurs.

How does the manual reset (MR) input affect both reset outputs in MAX6392KA44+?

The MR input on MAX6392KA44+ is an active-low signal with internal 47kΩ pullup to VCC. When pulled low, it forces immediate and synchronous assertion of both RESET1 (push-pull) and RESET2 (open-drain), regardless of VCC or RESET IN2 status. After MR returns high, RESET1 deasserts after its fixed 140ms timeout, and RESET2 follows only after RESET1 is deasserted and its own timeout expires-preserving sequenced behavior even after manual intervention.

Can MAX6392KA44+ monitor a 1.2V supply as the secondary voltage?

Yes, MAX6392KA44+ can monitor a 1.2V supply on RESET IN2 using an external resistive divider. With its internal 625mV reference, a divider ratio of R3/R4 = (1.2V / 0.625V) − 1 ≈ 0.92 sets the threshold. For example, using R4 = 500kΩ yields R3 ≈ 460kΩ. The MAX6392KA44+ guarantees valid comparison down to VCC = 1.0V, so 1.2V monitoring remains functional even during partial brownout conditions.

What is the purpose of the CSRT pin on MAX6392KA44+ and how is it configured?

The CSRT pin on MAX6392KA44+ selects RESET2 timeout mode: tying CSRT to VCC enables a fixed 140ms minimum delay, while connecting CSRT to an external capacitor (to ground) enables user-adjustable timeout calculated as tRP2 ≈ 2.08 × 10⁶ × CCSRT seconds. A 1500pF capacitor yields ~3.1ms, whereas larger values scale linearly. This flexibility allows precise alignment of RESET2 deassertion with downstream device requirements like FPGA configuration windows.

Does MAX6392KA44+ provide any protection against power supply noise or transients?

Yes, MAX6392KA44+ includes built-in immunity to short negative-going VCC transients: it rejects glitches ≤100ns wide when overdrive exceeds 10mV, per the Maximum Transient Duration vs. Reset Comparator Overdrive curve. This prevents false resets caused by switching noise or ESD-induced dips. The device also features hysteresis on both comparators and operates reliably down to VCC = 1.0V, enhancing robustness in electrically harsh environments.