Analog Devices Inc./Maxim Integrated MAX6451UT29L

Overview

MAX6451UT29L from Maxim Integrated is a dual-supply microprocessor supervisor IC with one fixed-threshold (2.925V) and one adjustable-threshold reset monitor, featuring one extended-setup manual reset input (MR1, t_MR = 6.72s) and one immediate-assertion manual reset input (MR2). It delivers active-low push-pull RESET output with 140ms minimum timeout, 6µA supply current, and guaranteed operation down to V_CC = 1.0V - used in set-top boxes and industrial equipment for reliable power-on reset and smart-card-detect functionality.

For engineers reviewing the MAX6451UT29L datasheet, MAX6451UT29L pinout, MAX6451UT29L application, or MAX6451UT29L equivalent, key selection considerations include its dual-mode manual reset architecture (extended + immediate), 2.925V fixed V_CC threshold, RSTIN-adjustable monitoring capability, SOT23-6 package, and push-pull RESET logic - critical for front-panel interrupt-before-reset and card-insertion detection designs.

Technical Context

The MAX6451UT29L integrates two independent reset comparators: one monitors V_CC against a factory-trimmed 2.925V threshold (±1.5% over -40°C to +85°C), while the second monitors RSTIN against a precise 0.63V reference, enabling external resistor-divider–based voltage monitoring down to 0.63V. Its MR1 input requires a sustained low pulse of 6.72s to trigger a one-shot RESET assertion, whereas MR2 responds immediately to a rising edge with internal 210ms debouncing on deassertion.

This dual-input architecture supports distinct system-level functions: MR1 serves as a deliberate, nuisance-immune hard-reset control (e.g., service-mode reset), while MR2 enables fast, glitch-resistant event detection (e.g., smart-card insertion). The push-pull RESET output drives µP reset inputs directly without external pull-up, sinking up to 3.2mA at V_CC ≥ 4.25V with VOL ≤ 0.4V.

Key Specifications

Pinout & Package

MAX6451UT29L is housed in a RoHS-compliant 6-pin SOT23 package (U6-1 outline), with 1.27mm pitch, 2.9mm × 1.6mm footprint, and thermal pad omitted. Pin 1 is marked by a dot or beveled corner.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6452UT29L and MAX6447UK29L, the MAX6451UT29L uniquely combines push-pull RESET, dual-mode manual reset (MR1+MR2), and RSTIN-adjustable monitoring in one SOT23-6 package - making it optimal for space-constrained, multi-rail systems requiring both deliberate reset and event-triggered signaling.

Availability

MAX6451UT29L is available at Aetrix Electronics and suitable for set-top boxes, smart-card readers, industrial HMIs, and DVD players requiring stable component supply across extended temperature (-40°C to +85°C) and long-lifecycle production.

Supply support for MAX6451UT29L 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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power-management ICs for industrial, communications, and consumer applications.

The MAX6443–MAX6452 family was designed specifically for robust, low-power microprocessor supervision in noisy, space-constrained environments - emphasizing extended manual reset immunity, dual-supply monitoring, and guaranteed operation across wide voltage and temperature ranges.

FAQ

What is the exact reset threshold voltage for MAX6451UT29L?

The MAX6451UT29L has a factory-trimmed V_CC reset threshold of 2.925V, with ±1.5% tolerance over the full -40°C to +85°C operating range. This value is confirmed in Table 1 of the datasheet and applies specifically to the "29" suffix variant. The RSTIN input uses a separate 0.630V ±0.020V reference for adjustable monitoring.

Does MAX6451UT29L support monitoring a secondary voltage rail?

Yes. The MAX6451UT29L includes an RSTIN pin that accepts an external resistor divider to monitor a secondary voltage rail. With its precise 0.630V internal reference, the MAX6451UT29L can accurately supervise voltages as low as 0.63V - enabling core voltage, I/O supply, or auxiliary rail monitoring without additional components.

What is the function of MR2 on MAX6451UT29L?

MR2 on the MAX6451UT29L is an immediate-assertion manual reset input: a rising edge triggers a one-shot RESET pulse (140ms min), and its falling edge is debounced for 210ms to prevent false triggers during removal events. This makes MR2 ideal for smart-card detect, test-mode entry, or other fast-response system events.

Can MAX6451UT29L operate with V_CC below 1.0V?

No - the MAX6451UT29L guarantees valid RESET output only down to V_CC = 1.0V. Below this, RESET current-sinking capability degrades significantly. For applications requiring reset validity down to 0V, a pulldown resistor (e.g., 100kΩ) must be added to the push-pull RESET output, as documented in Figure 9 of the MAX6451UT29L datasheet.

What package type and dimensions does MAX6451UT29L use?

The MAX6451UT29L is supplied in a 6-pin SOT23 package (package code U6-1), measuring 2.9mm × 1.6mm with 1.27mm lead pitch. It is RoHS-compliant and available in both leaded (-T) and lead-free (+T) variants. Land pattern number 90-0175 applies for PCB layout.