Analog Devices Inc./Maxim Integrated MAX6445UK23L+T

Overview

MAX6445UK23L+T from Maxim Integrated is a dual manual-reset microprocessor supervisor IC with fixed 2.313V VCC reset threshold, 6.72s extended setup period for both MR1 and MR2 inputs, push-pull active-low RESET output, and guaranteed operation from -40°C to +85°C in 5-pin SOT23 package. It monitors a single supply (VCC) and asserts RESET when voltage drops below threshold or when both manual reset inputs are held low ≥6.72s - used in set-top boxes and cable modems to prevent nuisance resets from front-panel button presses.

For engineers reviewing the MAX6445UK23L+T datasheet, MAX6445UK23L+T pinout, MAX6445UK23L+T application, or MAX6445UK23L+T equivalent, key selection criteria include its dual extended-setup manual reset architecture, 2.313V precision reset threshold, 6.72s tMR timing, push-pull RESET drive capability, and SOT23-5 package compatibility with space-constrained consumer electronics designs.

Technical Context

The MAX6445UK23L+T implements a dual-input manual reset logic requiring simultaneous assertion of MR1 and MR2 for ≥6.72s to trigger a one-shot 140ms–280ms RESET pulse. Its internal 50kΩ pullup on each MR input enables direct connection to mechanical switches without external components.

VCC monitoring uses a precision bandgap-based comparator with 60ppm/°C tempco and 2×VTH hysteresis. RESET remains asserted for 210ms (typ) after VCC recovers above 2.313V, ensuring stable processor initialization during brownout recovery.

Key Specifications

Pinout & Package

MAX6445UK23L+T is housed in a 5-pin SOT23 package (package code U5+1), with 0.95mm pitch, 2.9mm × 1.6mm body, and exposed pad not connected internally.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6445UK23L+T, MAX6446UK23L+T offers identical timing and threshold but requires external pullup for RESET, while TPS3808G33DBVR reduces current consumption by 60% but removes dual manual reset functionality - making MAX6445UK23L+T uniquely suited for secure, noise-immune reset in consumer HMI systems.

Availability

MAX6445UK23L+T is available at Aetrix Electronics and suitable for set-top boxes, cable modems, and DVD players requiring stable component supply, long-life industrial qualification, and RoHS-compliant packaging.

Supply support for MAX6445UK23L+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 demanding industrial, communications, and consumer applications.

The MAX6443–MAX6452 family delivers robust µP supervision with extended manual reset setup periods, targeting applications where accidental resets from front-panel switches must be eliminated - especially in set-top boxes, modems, and portable media devices.

FAQ

What is the exact reset threshold voltage of the MAX6445UK23L+T?

The MAX6445UK23L+T has a factory-trimmed VCC reset threshold of 2.313V, with ±0.075V tolerance over temperature. This value is defined by the "23" suffix per Table 1 in the datasheet and is guaranteed across the -40°C to +85°C operating range. The threshold exhibits 60ppm/°C tempco and includes 2×VTH hysteresis to prevent chatter near the trip point.

How does the dual manual reset function work on the MAX6445UK23L+T?

The MAX6445UK23L+T requires both MR1 and MR2 inputs to be held low simultaneously for the full 6.72s (L suffix) extended setup period before asserting RESET. Neither input alone triggers reset - this dual-input requirement prevents accidental activation from single-switch bounce or ESD events. Internal 50kΩ pullups eliminate need for external resistors.

Is the RESET output of the MAX6445UK23L+T push-pull or open-drain?

The MAX6445UK23L+T features an active-low push-pull RESET output, confirmed by its ordering code "U" (SOT23-5) and "K" (2.313V threshold) with no "/T" or "/V" suffix indicating open-drain variant. This allows direct drive of microprocessor reset pins without external pullup resistors, sinking up to 3.2mA at VCC ≥4.25V.

What is the minimum VCC voltage at which MAX6445UK23L+T guarantees valid RESET operation?

The MAX6445UK23L+T guarantees valid RESET logic state down to VCC = 1.0V, as specified in Absolute Maximum Ratings and Electrical Characteristics. Below 1.0V, RESET behavior is not guaranteed - for applications requiring assertion down to 0V, an external pulldown resistor is recommended per Figure 9 in the datasheet.

Does the MAX6445UK23L+T support adjustable voltage monitoring via RSTIN?

No, the MAX6445UK23L+T does not include an RSTIN pin and cannot monitor external voltages. It is a single-supply supervisor monitoring only VCC. Adjustable monitoring is exclusive to MAX6449–MAX6452 variants (6-pin SOT23), which feature the RSTIN input for external resistor-divider configuration.