Analog Devices Inc./Maxim Integrated MAX6392KA26+T

Overview

MAX6392KA26+T from Maxim Integrated is a dual-voltage microprocessor supervisory circuit with sequenced reset outputs, monitoring VCC (2.63V factory-fixed threshold) and adjustable RESET IN2 (625mV reference), 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 MAX6392KA26+T datasheet, MAX6392KA26+T pinout, MAX6392KA26+T application, or MAX6392KA26+T 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 MAX6392KA26+T implements two independent voltage comparators: one fixed-threshold (2.63V ±70mV) monitor on VCC for primary reset generation, and a secondary comparator referenced to 625mV on RESET IN2, enabling user-defined slave-supply monitoring via external resistor divider. RESET1 is push-pull active-low with internal 47kΩ MR pullup; RESET2 is open-drain with separate R2 pullup terminal.

Sequencing logic ensures RESET2 deasserts after RESET1 during power-up and asserts before RESET1 during power-down, enforced by dedicated delay chains - tRP1 fixed at 140–280ms, while tRP2 is either fixed (CSRT tied to VCC) or capacitor-adjustable (CSRT to ground). MR input forces both resets low within 10µs, with skew-controlled release timing.

Key Specifications

Pinout & Package

MAX6392KA26+T is housed in an 8-pin SOT23-8 package (3.00mm × 1.75mm × 1.30mm body, 0.65mm pitch), optimized for high-density PCB layouts in space-constrained industrial and computing applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6391KA26+T, the MAX6392KA26+T adds MR-driven synchronous reset and push-pull RESET1 for reduced external component count; versus TPS3808G33DBVR, it provides true dual-rail supervision, hardware-enforced sequencing, and lower operating voltage support (1V vs 1.8V min).

Availability

MAX6392KA26+T is available at Aetrix Electronics and suitable for industrial PLC controllers, server/workstation power management, and medical diagnostic equipment requiring stable component supply, long-term lifecycle assurance, and lead-free compliance.

Supply support for MAX6392KA26+T 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 MAX6391/MAX6392 product line delivers integrated dual-supply supervision with hardware-enforced reset sequencing, targeting high-reliability embedded systems where discrete reset solutions increase design risk and board area.

FAQ

What is the factory-set VCC reset threshold voltage for MAX6392KA26+T?

The MAX6392KA26+T has a factory-set VCC reset threshold of 2.63V, with a tolerance of ±70mV across the -40°C to +85°C temperature range. This value is laser-trimmed during production and cannot be adjusted. It defines the precise voltage at which the device asserts RESET1 and RESET2 during power-down or brownout events, and is confirmed in the Electrical Characteristics table under "VCC Reset Threshold (VTH1)" for ordering suffix "KA26".

How does the CSRT pin configure RESET2 timeout behavior in MAX6392KA26+T?

In the MAX6392KA26+T, the CSRT pin selects between fixed and adjustable RESET2 timeout: tying CSRT to VCC enables a fixed 140ms (min) delay, while connecting CSRT to a capacitor (to ground) enables user-adjustable delay calculated as tRP2 = 2.08 × 10⁶ × CCSRT seconds. The internal 600nA current source charges the capacitor to a 1.25V reference, and the resulting ramp time determines the timeout. This dual-mode flexibility allows designers to optimize sequencing without adding external timers.

Does MAX6392KA26+T support manual reset, and how is it implemented?

Yes, the MAX6392KA26+T includes an active-low manual reset (MR) input on pin 8. When pulled low (≤0.3×VCC), MR forces both RESET1 and RESET2 low within 10µs (RESET1) or 100ns (RESET2), with controlled skew. The MR pin features an internal 47kΩ pullup to VCC, so it may be left floating or tied to VCC when unused. This function is exclusive to the MAX6392 variant - the MAX6391 lacks MR and instead provides R1 pullup on pin 8.

What is the minimum VCC voltage at which MAX6392KA26+T guarantees valid reset operation?

The MAX6392KA26+T guarantees valid reset assertion and timing down to VCC = 1.0V, as specified in the Electrical Characteristics table under "Reset Pullup Resistance" and confirmed in the Detailed Description section. This ensures reliable brownout detection and reset hold-off even during deep undervoltage conditions where many competing supervisors cease functioning - a critical feature for fail-safe operation in industrial and medical systems.

Can MAX6392KA26+T monitor a secondary supply lower than 1V using the RESET IN2 input?

Yes, the MAX6392KA26+T can monitor secondary supplies as low as 625mV using the RESET IN2 input, because its internal comparator references a fixed 625mV threshold. To monitor voltages below 1V (e.g., 0.8V), an external resistive divider is required: R3 and R4 are selected such that VRST = 625mV × (R3 + R4)/R4. For example, monitoring 0.8V requires R3/R4 ≈ 0.28, making it feasible with standard E96 values - enabling supervision of modern ultra-low-voltage rails.