Analog Devices Inc./Maxim Integrated MAX6446UK23L

Overview

The MAX6446UK23L from Maxim Integrated is a dual-input, fixed-threshold microprocessor supervisory circuit with extended manual reset setup period and active-low open-drain RESET output. It monitors a single supply (VCC) at 2.313V ±1.5%, asserts RESET for ≥140ms after voltage recovery or manual reset assertion, and features two extended-setup manual reset inputs (MR1/MR2) requiring simultaneous 6.72s low hold to trigger. Used in set-top boxes and cable modems for reliable power-on reset and front-panel-initiated system recovery.

For engineers reviewing the MAX6446UK23L datasheet, MAX6446UK23L pinout, MAX6446UK23L application, or MAX6446UK23L equivalent, key selection considerations include its 2.313V VCC threshold, 6.72s dual-MR setup timeout, SOT23-5 package, -40°C to +85°C operation, and immunity to <100ns glitches on MR inputs - critical for consumer electronics with mechanical pushbuttons.

Technical Context

The MAX6446UK23L implements a precision bandgap-based voltage monitor for VCC with factory-trimmed 2.313V threshold and 60ppm/°C tempco. Its dual manual reset architecture requires both MR1 and MR2 to be held low simultaneously for 6.72s before generating a one-shot RESET pulse, preventing nuisance resets from accidental button presses.

RESET is open-drain with guaranteed low-level sink capability down to VCC = 1.0V (≤0.3V at 3.2mA), and includes internal 50kΩ pullups on MR1/MR2. The device ignores MR transitions shorter than 100ns and guarantees valid reset assertion even during fast VCC transients down to 1.0V supply.

Key Specifications

Pinout & Package

MAX6446UK23L is housed in a 5-pin SOT23 package (package code U5+1), with 1.3mm × 2.9mm footprint and 0.95mm height, optimized for space-constrained consumer PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6446UK23L, MAX6445UK23L offers identical electrical and timing behavior in the same package, while TPS3808G125DBVR trades dual-MR immunity for lower power and single-input simplicity - making it unsuitable for applications requiring deliberate multi-button reset confirmation.

Availability

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

Supply support for MAX6446UK23L 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 consumer applications.

The MAX6443–MAX6452 family delivers robust microprocessor supervision with extended manual reset setup periods, targeting consumer electronics and industrial equipment where mechanical switch reliability is critical.

FAQ

What is the exact reset threshold voltage for MAX6446UK23L and how is it specified?

The MAX6446UK23L has a factory-set VCC reset threshold of 2.313V, with ±1.5% tolerance over the full -40°C to +85°C temperature range. This value is defined in Table 1 of the datasheet under suffix "23", and the tempco is 60ppm/°C. The threshold is trimmed during production and does not require external adjustment.

Does MAX6446UK23L support dual manual reset inputs, and what is the required setup time?

Yes, MAX6446UK23L supports two extended manual reset inputs (MR1 and MR2). Both must be held low simultaneously for the full 6.72s (L suffix) before RESET is asserted. This dual-input requirement prevents accidental resets and is explicitly confirmed in the Pin Configurations table and Manual Reset Input Options section.

What package type and pin count does MAX6446UK23L use, and is it RoHS-compliant?

MAX6446UK23L uses a 5-pin SOT23 package (outline 21-0057, land pattern 90-0174), with top mark "UK23L". Per the Ordering Information table and Package Information section, the "+T" suffix indicates lead(Pb)-free (RoHS-compliant) packaging, and this is standard for all current production units.

Can MAX6446UK23L operate with supply voltages below 1.8V, and what is its minimum functional VCC?

Yes, MAX6446UK23L operates down to VCC = 1.0V, and its RESET output is guaranteed functional (valid logic state) at that voltage. The Electrical Characteristics table specifies "Guaranteed Valid Reset Down to VCC = 1.0V", and the Absolute Maximum Ratings confirm VCC as low as -0.3V (stress) with operational range starting at 1.0V.

Is MAX6446UK23L pin-compatible with other parts in the MAX6443–MAX6452 family, and which ones share the same SOT23-5 footprint?

MAX6446UK23L is pin-compatible with MAX6445UKxxL, MAX6447UKxxL, and MAX6448UKxxL - all use the 5-pin SOT23 package with identical pinout (GND-VCC-MR1-MR2-RESET). This compatibility is confirmed in the Pin Configurations diagram and Selector Guide, enabling direct substitution within the same package variant.