Analog Devices Inc./Maxim Integrated MAX6450UT29L+T

Overview

The MAX6450UT29L+T from Maxim Integrated is a dual-supply microprocessor reset supervisor IC with one fixed-threshold (2.925V) and one adjustable-threshold (0.63V reference) voltage monitor, dual extended-setup manual reset inputs (MR1/MR2), open-drain active-low RESET output, and 6.72s manual reset setup period - designed for reliable system initialization in consumer electronics and industrial equipment where nuisance resets must be avoided.

For engineers reviewing the MAX6450UT29L+T datasheet, MAX6450UT29L+T pinout, MAX6450UT29L+T application, or MAX6450UT29L+T equivalent, key selection considerations include its dual manual reset architecture with long tMR timing, adjustable RSTIN threshold down to 0.63V, guaranteed RESET assertion down to VCC = 1.0V, and SOT23-6 package compatibility with space-constrained embedded designs.

Technical Context

This device implements two independent reset comparators: one monitors VCC against a factory-trimmed 2.925V threshold (±1.5% over -40°C to +85°C), while the second monitors an external voltage via RSTIN using a precision 0.630V internal reference with 2.5mV hysteresis. Both comparators feed into a shared reset timeout timer with 210ms typical deassertion delay after all supplies recover.

The MAX6450UT29L+T features dual active-low manual reset inputs - MR1 and MR2 - both requiring simultaneous low assertion for ≥6.72s (tMR = L suffix) before generating a 140ms minimum one-shot RESET pulse; it includes internal 50kΩ pullups on MR1/MR2 and supports glitch rejection up to 100ns on MR2, with no external debounce circuitry needed.

Key Specifications

Pinout & Package

MAX6450UT29L+T is housed in a 6-pin SOT23 package (U6+1 outline), measuring 2.9mm × 1.6mm × 1.1mm, with gull-wing leads and RoHS-compliant lead-free finish (+T suffix). The package is rated for operation from −40°C to +85°C and supports reflow soldering at +260°C (lead-free).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6446UK29L+T, the MAX6450UT29L+T adds critical RSTIN-based multi-rail supervision; compared with MAX6452UT29L+T, it omits immediate MR2 triggering - making it optimal for cost-sensitive, dual-rail systems requiring robustness against accidental resets but no fast-event response.

Availability

MAX6450UT29L+T is available at Aetrix Electronics and suitable for consumer electronics, industrial HMIs, and cable/DSL modem designs requiring stable component supply, long-term lifecycle support, and guaranteed performance across −40°C to +85°C.

Supply support for MAX6450UT29L+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 management, sensing, and interface applications - with emphasis on high-reliability, low-power, and automotive-qualified solutions.

The MAX6443–MAX6452 family was developed specifically for robust microprocessor supervision in noise-prone consumer and industrial environments, featuring extended manual reset timing, dual-supply monitoring, and ultra-low ICC to replace discrete RC-reset circuits.

FAQ

What is the exact reset threshold voltage for MAX6450UT29L+T?

The MAX6450UT29L+T has a factory-trimmed VCC reset threshold of 2.925V (±1.5% over temperature), corresponding to the "29" suffix per Table 1. Its RSTIN input uses a precise 0.630V internal reference (±0.020V over −40°C to +85°C) to enable adjustable monitoring of external rails.

Does MAX6450UT29L+T support both push-pull and open-drain RESET outputs?

No - the MAX6450UT29L+T is specified with open-drain RESET output only, as confirmed by its ordering code (+T) and Pin Configuration table. It requires an external pullup resistor (minimum 20kΩ) to VCC or another logic rail, enabling voltage-level translation and wired-OR reset bus implementation.

How does the dual manual reset function work on MAX6450UT29L+T?

The MAX6450UT29L+T requires both MR1 and MR2 pins to be held low simultaneously for ≥6.72 seconds (tMR = L suffix) to assert RESET. This dual-input requirement prevents accidental resets - for example, a user must press two distinct buttons or hold one button for the full duration while another signal is asserted.

Can MAX6450UT29L+T monitor a 1.2V supply rail?

Yes - the MAX6450UT29L+T monitors adjustable rails via RSTIN using a 0.630V internal reference. To supervise a 1.2V rail, connect RSTIN to the center tap of a resistor divider (e.g., R1 = 220kΩ, R2 = 250kΩ), yielding VMON-TH = 0.63 × (220k + 250k)/250k ≈ 1.18V, well within specification.

What is the minimum VCC voltage at which MAX6450UT29L+T guarantees valid RESET output?

The MAX6450UT29L+T guarantees correct RESET logic state (low when asserted, high-impedance when deasserted) for VCC ≥ 1.0V, as stated in Absolute Maximum Ratings and Electrical Characteristics. Below 1.0V, RESET behavior is not guaranteed - consistent with its design for brownout detection rather than zero-volt operation.