Analog Devices Inc./Maxim Integrated MAX6444US16L+

Overview

MAX6444US16L+ from Maxim Integrated is a single-supply, fixed-threshold microprocessor reset supervisor with one extended-setup manual reset input (MR1), active-low open-drain RESET output, 1.575V VCC reset threshold, and 6.72s manual reset setup period. It monitors VCC only, asserts RESET when VCC drops below threshold or MR1 is held low ≥6.72s, and guarantees valid reset down to VCC = 1.0V. Used in consumer electronics power sequencing and brownout protection.

For engineers reviewing the MAX6444US16L+ datasheet, MAX6444US16L+ pinout, MAX6444US16L+ application, or MAX6444US16L+ equivalent, key selection considerations include its 1.575V fixed reset threshold, 6.72s extended manual reset setup time, SOT143-4 package, 6µA supply current, and immunity to <100ns glitches - critical for reliable front-panel reset implementation in set-top boxes and DVD players.

Technical Context

The MAX6444US16L+ implements a precision bandgap-based voltage monitor with 60ppm/°C tempco and 2×VTH hysteresis, ensuring stable reset assertion across -40°C to +85°C. Its internal 50kΩ MR1 pullup enables direct connection to momentary switches without external components.

RESET is a one-shot pulse asserted for 140ms (min) / 210ms (typ) after VCC recovery or MR1 activation. The open-drain output requires an external pullup (≥20kΩ to VCC) and sinks up to 3.2mA at VCC ≥4.25V while maintaining VOL ≤0.4V.

Key Specifications

Pinout & Package

SOT143-4 surface-mount package with 1.3mm × 2.1mm body, 0.95mm height, and 0.65mm lead pitch. RoHS-compliant lead-free construction (indicated by '+' suffix).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6444US16L+, MAX6443US16L+ offers identical supervision parameters but eliminates the need for an external pullup resistor at the cost of flexibility, while TPS3808G16DBVR reduces supply current by 73% but removes the core extended-setup manual reset capability essential for consumer front-panel interfaces.

Availability

MAX6444US16L+ is available at Aetrix Electronics and suitable for set-top box manufacturing, DVD player production, and cable modem assembly requiring stable component supply with guaranteed long-term availability.

Supply support for MAX6444US16L+ 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 management, sensing, and interface applications.

The MAX6443–MAX6452 family delivers robust µP reset supervision with extended manual reset setup periods specifically for consumer electronics requiring tamper-resistant front-panel reset functionality.

FAQ

What is the exact reset threshold voltage of the MAX6444US16L+?

The MAX6444US16L+ has a factory-trimmed VCC reset threshold of 1.575V, specified with ±1.5% tolerance over -40°C to +85°C and 60ppm/°C temperature coefficient. This value is confirmed in Table 1 of the datasheet, where the "16" suffix corresponds to 1.575V. The MAX6444US16L+ uses this precise threshold to detect brownout conditions on 1.6V nominal supply rails.

How does the 6.72s manual reset setup period prevent nuisance resets in the MAX6444US16L+?

The MAX6444US16L+ requires MR1 to be held low for a minimum of 6.72 seconds (the "L" suffix) before asserting RESET, effectively ignoring brief button presses caused by accidental contact or mechanical bounce. This extended setup period is implemented with internal RC timing and debouncing circuitry, eliminating the need for external hardware filters. The MAX6444US16L+ thus enables a single front-panel button to serve dual functions: short press for menu navigation and 6.72s press for hard reset.

Can the MAX6444US16L+ operate with supply voltages below 1.6V?

Yes, the MAX6444US16L+ operates over 1.0V to 5.5V and guarantees valid RESET output down to VCC = 1.0V, as stated in the Electrical Characteristics table. Below 1.0V, RESET behavior is not specified. The MAX6444US16L+ achieves this with optimized BiCMOS process design, allowing reliable brownout detection even as the monitored supply collapses toward 1.0V - critical for graceful shutdown in battery-powered devices.

What is the function of the open-drain RESET output in the MAX6444US16L+?

The MAX6444US16L+ features an active-low open-drain RESET output that requires an external pullup resistor (≥20kΩ to VCC) to establish the high state. This configuration allows level-shifting to different logic supplies, wired-OR reset bus connections, and compatibility with µPs having non-3.3V reset inputs. When asserted, the MAX6444US16L+ sinks up to 3.2mA while maintaining VOL ≤0.4V at VCC ≥4.25V, ensuring robust reset signaling across voltage domains.

Does the MAX6444US16L+ support monitoring of auxiliary voltages like RSTIN?

No, the MAX6444US16L+ monitors only the VCC supply and does not include the RSTIN pin found on MAX6449–MAX6452 variants. Its pinout (SOT143-4) contains GND, RESET, MR1, and VCC only - confirming it is a single-supply, fixed-threshold device per the Selector Guide. For adjustable-voltage monitoring, designers must select MAX6449UT16L+ or similar RSTIN-equipped variants instead of the MAX6444US16L+.