Analog Devices Inc./Maxim Integrated MAX6455UT29S+T

Overview

MAX6455UT29S+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 2.925V, adjustable RSTIN monitoring down to 0.63V, 140ms min 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 MAX6455UT29S+T datasheet, MAX6455UT29S+T pinout, MAX6455UT29S+T application, or MAX6455UT29S+T equivalent, key selection criteria include its dual-output architecture (RESET + MROUT), 2.925V fixed VCC threshold, 3.36s MR setup period enabling interrupt-before-reset functionality, push-pull output drive capability, and guaranteed valid reset operation down to VCC = 1.0V.

Technical Context

The MAX6455UT29S+T implements a dual-comparator architecture: one precision bandgap-based comparator monitors VCC against a factory-trimmed 2.925V threshold, while a second high-impedance comparator monitors RSTIN against a fixed 0.63V reference-enabling external resistor-divider configuration for secondary voltage supervision. Its MR input controls both outputs: brief MR assertion triggers only MROUT (soft interrupt), while sustained MR low ≥3.36s asserts both MROUT and RESET (hard reboot).

This behavior is enabled by an internal timing circuit that distinguishes MR pulse width using a dedicated RC-based setup timer. The push-pull RESET output guarantees logic-level compatibility without external pullups, sinking up to 3.2mA at VCC ≥4.25V, and remains functional across the full -40°C to +85°C industrial temperature range with 60ppm/°C reset threshold tempco.

Key Specifications

Pinout & Package

MAX6455UT29S+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 and RoHS-compliant finish indicated by the "+T" suffix.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6455UT29S+T, the MAX6455UT29D+T offers identical supervision logic but demands external pullups, increasing BOM and layout complexity; the TPS3808G33DBVR lacks RSTIN adjustability and MR-controlled dual-output functionality, restricting use to basic single-rail reset applications without interrupt-before-reset capability.

Availability

MAX6455UT29S+T is available at Aetrix Electronics and suitable for set-top boxes, DVD players, and cable modems requiring stable component supply, long-term industrial temperature support (-40°C to +85°C), and RoHS-compliant packaging.

Supply support for MAX6455UT29S+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 industrial, communications, and consumer applications, with emphasis on power management, sensing, and interface solutions.

The MAX6453–MAX6456 family was engineered specifically for dual-rail microprocessor supervision in space-constrained consumer and industrial systems, integrating factory-trimmed thresholds, adjustable monitoring, and intelligent manual reset logic to replace discrete reset circuits.

FAQ

What is the exact VCC reset threshold voltage for MAX6455UT29S+T?

The MAX6455UT29S+T has a factory-trimmed VCC reset threshold of 2.925V, with a guaranteed tolerance of ±0.075V (2.85V to 3.00V) over temperature. This value is confirmed in Table 1 of the datasheet under suffix "29", and applies specifically to the MAX6455UT29S+T variant-not other members of the MAX6455 family. The threshold exhibits 60ppm/°C tempco and 2.5mV hysteresis.

How does the manual reset input function on MAX6455UT29S+T?

On the MAX6455UT29S+T, the MR input controls both RESET and MROUT outputs. A low pulse shorter than 3.36s asserts only MROUT (soft interrupt); a pulse ≥3.36s asserts both MROUT and RESET (hard reboot). The internal 50kΩ pullup ensures MR defaults high. This dual-mode behavior is unique to the MAX6455/MAX6456 series and is not present in MAX6453/MAX6454 variants.

Can MAX6455UT29S+T monitor a 1.2V supply rail?

Yes, the MAX6455UT29S+T can monitor a 1.2V rail using its RSTIN pin. With a fixed 0.63V internal reference, a resistor divider (e.g., R1 = 220kΩ, R2 = 250kΩ) sets the trip point to 1.2V per VMON_TH = 0.63 × (R1 + R2)/R2. The high-impedance RSTIN input draws only ±25nA, minimizing divider current. This capability is explicitly supported and characterized in the datasheet's Applications Information section.

What is the minimum operating voltage for MAX6455UT29S+T to guarantee valid RESET output?

The MAX6455UT29S+T guarantees valid RESET output down to VCC = 1.0V. Below this, current-sinking capability degrades, risking indeterminate logic states. This specification is tested and guaranteed across the full -40°C to +85°C temperature range. For operation below 1.0V, a pulldown resistor (e.g., 100kΩ) on the push-pull RESET output is recommended-though not required for standard use cases.

Is MAX6455UT29S+T pin-compatible with other devices in the MAX6453–MAX6456 family?

Yes, all MAX6453–MAX6456 devices, including MAX6455UT29S+T, share identical SOT23-6 pinouts and footprint (U6-1 land pattern). Pin 1 is RESET, Pin 2 is GND, Pin 3 is MROUT, Pin 4 is VCC, Pin 5 is RSTIN, and Pin 6 is MR. However, functional differences exist: MAX6455/MAX6456 tie MR to both outputs, while MAX6453/MAX6454 isolate MR to MROUT only-so electrical compatibility requires verifying the intended reset logic.