Analog Devices Inc./Maxim Integrated MAX6455UT26S+T

Overview

MAX6455UT26S+T from Maxim Integrated is a dual-voltage microprocessor supervisor IC with separate active-low push-pull RESET and MROUT outputs, factory-set VCC reset threshold of 2.625V (±1.5%), adjustable RSTIN monitoring down to 0.63V, 140ms minimum reset timeout, and manual reset input supporting soft/hard reset combination via extended 3.36s setup period. It operates from 1.0V to 5.5V supply and is used in set-top boxes and consumer electronics for reliable power-on reset and controlled system recovery.

For engineers reviewing the MAX6455UT26S+T datasheet, MAX6455UT26S+T pinout, MAX6455UT26S+T application, or MAX6455UT26S+T equivalent, key selection criteria include its dual-output architecture, 2.625V fixed VCC threshold, 3.36s MR setup period enabling interrupt-before-reset functionality, push-pull output drive capability, and guaranteed valid reset assertion down to VCC = 1.0V.

Technical Context

The MAX6455UT26S+T implements a dual-comparator architecture: one precision bandgap-based comparator monitors VCC against a factory-trimmed 2.625V threshold (±1.5% over –40°C to +85°C), while a second high-impedance comparator monitors RSTIN with a fixed 0.63V reference, enabling external voltage divider-based monitoring of secondary rails. Its MR input controls both outputs-short press asserts only MROUT (soft interrupt), long press (>3.36s) asserts both MROUT and RESET (hard reboot).

This architecture enables deterministic sequencing: MROUT deasserts 140ms after MR release, while RESET deasserts 140ms after MR release only if MR was held ≥3.36s. The push-pull outputs drive directly into µP reset/NMI pins without external pullups, and internal 50kΩ MR pullup simplifies button interface design.

Key Specifications

Pinout & Package

MAX6455UT26S+T is housed in a lead(Pb)-free SOT23-6 package (package code U6-1), measuring 2.9mm × 1.6mm × 1.1mm, with gull-wing leads compatible with standard reflow profiles (260°C peak for RoHS).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6455UT26S+T, the leaded -T variant requires Pb-process compatibility and lacks RoHS certification, while the UT29S+T variant shifts the reset threshold upward by 300mV-making it appropriate for higher-voltage rails but incompatible for 2.5V–2.7V system validation.

Availability

MAX6455UT26S+T is available at Aetrix Electronics and suitable for set-top boxes, DVD players, and cable modems requiring stable component supply, RoHS-compliant packaging, and guaranteed long-term availability for industrial embedded programs.

Supply support for MAX6455UT26S+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, mixed-signal, and power management ICs for industrial, communications, and consumer applications.

The MAX6453–MAX6456 family delivers dual-output µP supervisors optimized for systems needing both interrupt-capable soft reset and unconditional hard reset, with factory-trimmed thresholds and extended MR timing to simplify front-panel control design.

FAQ

What is the factory-set VCC reset threshold voltage for MAX6455UT26S+T?

The MAX6455UT26S+T has a factory-set VCC reset threshold of 2.625V, with ±1.5% tolerance over the full –40°C to +85°C operating temperature range. This value is laser-trimmed during production and specified in Table 1 of the datasheet under suffix "26". It is designed to reliably detect brownout on 2.5V or 2.7V nominal power rails while maintaining noise margin.

How does the manual reset input (MR) function differently on MAX6455UT26S+T compared to MAX6453UT26S+T?

On MAX6455UT26S+T, the MR input controls both MROUT and RESET outputs: a short press (<3.36s) asserts only MROUT, while a long press (≥3.36s) asserts both MROUT and RESET. In contrast, MAX6453UT26S+T's MR affects only MROUT-the RESET output responds solely to VCC/RSTIN voltage faults. This makes MAX6455UT26S+T suitable for interrupt-before-reset architectures.

Does MAX6455UT26S+T require external pullup resistors on its RESET and MROUT outputs?

No, MAX6455UT26S+T features active-low push-pull outputs on both RESET and MROUT pins, eliminating the need for external pullup resistors. Each output can source up to 200µA and sink up to 1.2mA (at VCC ≥ 2.55V), allowing direct connection to standard CMOS µP reset and NMI inputs without additional components.

Can MAX6455UT26S+T monitor a secondary voltage lower than 1.0V?

Yes, MAX6455UT26S+T can monitor secondary voltages as low as 0.63V using the RSTIN pin. Its internal comparator uses a precise 0.630V reference (±1.6% over temperature), and an external resistor divider scales the target rail voltage to match this reference-enabling accurate supervision of 0.8V, 0.9V, or 1.0V core supplies common in modern SoCs.

What is the minimum VCC voltage at which MAX6455UT26S+T guarantees valid RESET output assertion?

MAX6455UT26S+T guarantees valid RESET output assertion down to VCC = 1.0V. Below this level, current-sinking capability degrades, but the device remains functional across its full 1.0V–5.5V operating range. This ensures robust reset behavior during deep brownout events where other supervisors may fail to assert.