Analog Devices Inc./Maxim Integrated MAX6446UK23L-T

Overview

The MAX6446UK23L-T from Maxim Integrated is a dual-input, fixed-threshold microprocessor supervisory circuit in 5-pin SOT23 package, featuring two extended-setup manual reset inputs (MR1 and MR2), 2.313V VCC reset threshold, 6.72s minimum manual reset pulse width, and 140ms min reset timeout period. It ensures reliable system reset in consumer electronics and industrial equipment where nuisance resets from front-panel switches must be avoided.

For engineers reviewing the MAX6446UK23L-T datasheet, MAX6446UK23L-T pinout, MAX6446UK23L-T application, or MAX6446UK23L-T equivalent, key selection criteria include dual extended manual reset timing (tMR = 6.72s), guaranteed reset assertion down to VCC = 1.0V, push-pull RESET output, and immunity to transients <20µs at 100mV overdrive - critical for robust power-up/brownout monitoring in set-top boxes and modems.

Technical Context

The MAX6446UK23L-T implements a precision bandgap-based voltage monitor with 60ppm/°C tempco and 2×VTH hysteresis, asserting active-low RESET when VCC drops below 2.313V. Its dual MR1/MR2 inputs require simultaneous low assertion for ≥6.72s to trigger a one-shot 140ms–280ms reset pulse, eliminating false triggers from momentary switch closures.

Unlike immediate-reset supervisors, this device uses internal 50kΩ pullups on both MR1 and MR2, debounces transitions, and guarantees valid RESET logic state across -40°C to +85°C. The push-pull output drives µP reset pins directly without external pullup, sinking 1.2mA at VCC ≥ 2.55V with VOL ≤ 0.3V.

Key Specifications

Pinout & Package

Package: 5-pin SOT23 (U5-1, outline 21-0057), surface-mount, lead(Pb)-free compatible (suffix -T denotes leaded; +T required for RoHS).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6445UK23L-T, the MAX6446UK23L-T offers identical core supervision but is distinguished by its open-drain RESET output option (though this part uses push-pull); versus TPS3808G33DBVR, it provides superior nuisance immunity via dual extended setup and higher threshold accuracy, at the cost of higher pin count and current draw.

Availability

MAX6446UK23L-T is available at Aetrix Electronics and suitable for set-top boxes, cable modems, DVD players, and industrial HMI panels requiring stable component supply with guaranteed -40°C to +85°C operation and long-term lifecycle support.

Supply support for MAX6446UK23L-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 and mixed-signal ICs for power, sensing, and interface applications, with emphasis on reliability and integration.

The MAX6443–MAX6452 family delivers microprocessor supervisory functions with extended manual reset setup periods, targeting consumer, industrial, and automotive systems where robust reset control under noisy or human-operated conditions is essential.

FAQ

What is the exact reset threshold voltage of the MAX6446UK23L-T?

The MAX6446UK23L-T has a factory-trimmed VCC reset threshold of 2.313V, with ±0.075V tolerance over temperature. This value is fixed by the "23" suffix per Table 1 and is guaranteed across -40°C to +85°C with 60ppm/°C tempco. The MAX6446UK23L-T does not support adjustable thresholds - that feature is exclusive to MAX6449–MAX6452 variants with RSTIN pin.

Does the MAX6446UK23L-T support open-drain or push-pull RESET output?

The MAX6446UK23L-T features a push-pull RESET output, as confirmed by the ordering matrix (MAX6446 row shows "✔" under "PUSH-PULL RESET"). This eliminates the need for an external pullup resistor and ensures strong drive capability: VOL ≤ 0.3V at 1.2mA sink current when VCC ≥ 2.55V. The MAX6446UK23L-T is not available with open-drain output - that variant is MAX6446UK23L-T's sibling MAX6446UK23L-T (open-drain version uses different suffix).

How does the dual manual reset function work on the MAX6446UK23L-T?

The MAX6446UK23L-T requires both MR1 and MR2 inputs to be held low simultaneously for ≥6.72s (L suffix) before asserting RESET. Internal 50kΩ pullups keep both inputs high by default. The device ignores any MR1 or MR2 transition shorter than 100ns and debounces edges to prevent false triggers. Once triggered, RESET pulses low for 140ms–280ms and then deasserts automatically - no latching or external clearing is needed. This dual-input coordination is unique to MAX6445/MAX6446/MAX6449/MAX6450 variants.

Can the MAX6446UK23L-T operate reliably during deep brownout conditions?

Yes, the MAX6446UK23L-T guarantees valid RESET assertion down to VCC = 1.0V, as specified in Electrical Characteristics. Its internal bandgap reference and comparator remain functional at this level, ensuring the RESET output stays low until VCC rises above 2.313V and holds for the 210ms timeout period. Below 1.0V, operation is not guaranteed - for VCC = 0V validity, a pulldown resistor is required (only applicable to push-pull versions like MAX6446UK23L-T).

What package type and footprint does the MAX6446UK23L-T use?

The MAX6446UK23L-T uses a 5-pin SOT23 package (package code U5-1, outline 21-0057), with 0.95mm pitch and standardized land pattern 90-0174. Pin 1 is GND, pin 2 is VCC, pin 3 is MR1, pin 4 is MR2, and pin 5 is RESET. This compact surface-mount package measures 2.9mm × 1.6mm × 1.1mm and supports reflow soldering at +240°C (leaded) or +260°C (lead-free). The MAX6446UK23L-T is supplied in tape-and-reel format only, with 2500-piece minimum order quantity.