Analog Devices Inc./Maxim Integrated MAX6456UT29S+T

Overview

MAX6456UT29S+T from Maxim Integrated is a dual-voltage microprocessor supervisor IC with separate active-low open-drain VCC reset and manual reset outputs, factory-set 2.925V VCC reset threshold, adjustable RSTIN monitoring down to 0.63V, 140ms minimum reset timeout, and extended 1.68s manual reset setup period enabling soft/hard system reset combination in embedded power management circuits.

For engineers reviewing the MAX6456UT29S+T datasheet, MAX6456UT29S+T pinout, MAX6456UT29S+T application, or MAX6456UT29S+T equivalent, this device supports interrupt-before-reset functionality, brownout immunity, low 6µA supply current, guaranteed valid reset down to VCC = 1.0V, and SOT23-6 footprint compatibility for space-constrained consumer and industrial designs.

Technical Context

The MAX6456UT29S+T implements a dual-comparator architecture: one precision bandgap reference comparator monitors VCC against a fixed 2.925V threshold, while a second high-impedance comparator monitors RSTIN against a fixed 0.63V internal reference-enabling external resistor-divider configuration for secondary voltage supervision. Its MR input controls both MROUT and RESET outputs via time-gated logic.

When MR is held low for ≥1.68s (typ), RESET asserts alongside MROUT; if MR is pulsed <1.68s, only MROUT asserts. Both outputs feature open-drain topology with 1µA leakage when deasserted, 0.3–0.4V VOL at ISINK = 50µA–3.2mA, and full operation across -40°C to +85°C.

Key Specifications

Pinout & Package

Package: SOT23-6, surface-mount, lead(Pb)-free (indicated by "+T" suffix), -40°C to +85°C operating range.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6456UT29S+T, MAX6455UT29S+T simplifies BOM by eliminating pullup resistors but sacrifices bus-sharing flexibility, while TPS3808G33DBVR reduces solution size and cost at the expense of critical dual-output and adjustable monitoring features required for robust system recovery.

Availability

MAX6456UT29S+T is available at Aetrix Electronics and suitable for set-top boxes, cable modems, portable medical devices, and industrial controllers requiring stable component supply, RoHS-compliant packaging, and long-term production continuity.

Supply support for MAX6456UT29S+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, sensing, and interface applications, with emphasis on reliability and integration for demanding environments.

The MAX6453–MAX6456 family was engineered specifically for embedded systems requiring coordinated soft/hard reset sequencing, dual-rail supervision, and ultra-low-power operation across extended temperature ranges.

FAQ

What is the exact VCC reset threshold voltage for MAX6456UT29S+T?

The MAX6456UT29S+T has a factory-set VCC reset threshold of 2.925V (minimum 2.85V, maximum 3.00V per datasheet Table). This value is laser-trimmed during production and applies specifically to the "29" suffix in the part number, ensuring consistent brownout detection for 3.3V systems without external calibration.

Does MAX6456UT29S+T support monitoring a 1.2V rail using the RSTIN pin?

Yes, MAX6456UT29S+T supports monitoring a 1.2V rail via RSTIN using an external resistor divider. With a fixed 0.63V internal reference, a standard divider (e.g., R1 = 909kΩ, R2 = 1MΩ) sets the trip point precisely at 1.2V using the formula VMON_TH = 0.63 × (R1 + R2)/R2. The high-impedance RSTIN input draws only ±25nA, minimizing divider current.

How does the manual reset function differ between MAX6456UT29S+T and MAX6454UT29S+T?

Unlike MAX6454UT29S+T-which asserts only MROUT on MR activation-MAX6456UT29S+T uses the same MR input to control both MROUT and RESET outputs. When MR is held low ≥1.68s, MAX6456UT29S+T asserts RESET in addition to MROUT, enabling a unified pushbutton for interrupt-or-reboot functionality not available in MAX6454UT29S+T.

What is the minimum VCC voltage at which MAX6456UT29S+T guarantees valid RESET output logic?

MAX6456UT29S+T guarantees valid active-low RESET output logic down to VCC = 1.0V, as confirmed in the Absolute Maximum Ratings and Electrical Characteristics tables. Below 1.0V, output sinking capability degrades; however, for applications requiring validity to 0V, a 100kΩ pulldown resistor is recommended-but only for push-pull variants, not MAX6456UT29S+T's open-drain outputs.

Can MAX6456UT29S+T be used in a system with a 5V microprocessor reset input?

Yes, MAX6456UT29S+T's open-drain RESET output can interface directly to a 5V µP reset input by connecting the external pullup resistor to the 5V rail. The datasheet confirms RESET tolerates up to +6V when deasserted, and its 0.4V max VOL at 3.2mA sink ensures solid low-state compatibility with 5V logic thresholds, provided the pullup value is selected to limit current within safe limits.